Full text of "Canning and preserving of food products with bacteriological technique; a practical and scientific hand book for manufacturers of food products, bacteriologists, chemists, and students of food problems. Also for processors and managers of food product manufactories"

EDWARD WILEY DUCKWALL
Director of the National Canners' Laboratory, Aspimvall, Pa.

CANNING and PRESERVING

of FOOD PRODUCTS with

BACTERIOLOGICAL

TECHNIQUE

A PRACTICAL AND SCIENTIFIC HAND BOOK
FOR MANUFACTURERS OF FOOD PRODUCTS,
BACTERIOLOGISTS, CHEMISTS AND
STUDENTS OF FOOD PROBLEMS.
ALSO FOR PROCESSORS AND
MANAGERS OF FOOD
PRODUCT MANU-
FACTORIES

EDWARD WILEY DUCKWALL, M. S.

r I

Bacteriologist for The National Canners' Laboratory. Member of the
Society of American Bacteriologists. Member of the American Chemical
Society. Member of the American Association for the Advancement of
Science. Bacteriologist for the Health Department, Aspinvirall, Pa.

PRESS OF

PITTSBURGH PRINTING COMPANY
PITTSBURGH, PA.

BENEBAL

AFFECTIONATELY DEDICATED TO THE MEMORY OF
MY FATHER,

THOMAS DUCKWALL,

WHO WAS THE PIONEER CANNER AND MANUFACTURER
OF FOOD PRODUCTS IN OHIO.

by
EDWARD W. DUCKWALL

Contents

CHAPTER 1.
THE LABORATORY AND ITS EQUIPMENT , . . . . 1 1

Apparatus Used in a Bacteriological and Food Laboratory, De-
scription of Lenses, Table of Reagents.

CHAPTER II.
BACTERIA 33

Description and Classification, Spore Formation, Nature of
Bacteria, Influence of Electricity on Bacteria, Influence of
Temperature, Influence of Light, Motility, Chromogenic
Bacteria, Bacterial Products; Slime, Ropiness, etc.

CHAPTER III.
PRINCIPLES OF BACTERIOLOGICAL TECHNIQUE 72

Methods of Cultivating Bacteria, Artificial Media, Method of
Cultivating Anaerobes, Methods of Simple Staining, Meth-
od of Staining Flagella, Method of Making Photomicro-
graphs.

CHAPTER IV.
DECOMPOSITION CAUSED BY MICRO-ORGANISMS 104

Fermentation Theories, Vacuum Theory, Alcoholic Fermenta-
tion, (Acetic Fermentation), Butyric Fermentation, Lactic
Fermentation, Putrefaction, Reprocessing Leaks a Danger-
our Proceeding.

CHAPTER V.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS (Con-
tinued) 161

Putrefaction, Bacteria of, Ptomaines and Toxins, Pathogenic
Bacteria and Their Actions on Foods.

CHAPTER VI.
STERILIZATION 208

Nature of Spores, Cleanliness in Manufacturing, Disposition of
Waste Material, The Venting Process, The Vacuum Ma-
chinery, Discontinuous Sterilization, Preservatives Formed
in Sterilization.

CHAPTER VII.
PRESERVATIVES 225

What are Preservatives? Preservatives are not Ordinarily
Used in Canned Goods, Some Food Products Require Them,
Natural Origin of Preservatives in Food Products, Statements
Made by Various Authorities Analyzed and Criticized,
Sterilized Catsup, Preserves and Fruit Butters not Satis-
factory to the Trade, Some Opposing Arguments Answered.

CONTENTS

CHAPTER VIII.

PRESERVATIVES (Continued) 247

Experiments with Preservatives and Other Substances to De-
termine Their Effect on Peptic Digestion, Physiological
and Pathological Research Work with Animals Fed on
Salicylic and Benzoic Acids; Post Mortems; Conclusions.

CHAPTER IX.
CHEMICAL ANTISEPTICS 286

Benzoic Acid, Methods of Detection, Salicylic Acid, Methods of
Detection, Formaldehyde, Methods of Detection, Boracic
Acid, Methods of Detection, Miquel's Table of Antiseptics
and Their Relative Value.

CHAPTER X.
ARTIFICIAL SWEETENERS AND ADULTERANTS 297

Saccharin, Method of Detection, Dulcin, Method of Detection,
Glucin, Sulphites, Method of Detection, Artificial Colors,
Starch, etc.

CHAPTER XL
THE CANNING INDUSTRY 311

A Short History, Location and Equipment of a Canning Fac-
tory, What to Can, Selection of Raw Material,

CHAPTER XII.
PEAS 324

History, Growing, The Leguminous and Nitrifying Bacteria,
The Pea Parasite, Chemical Composition and Food Value
of Peas, Methods of Canning, Machinery, Bacteria Asso-
ciated with Spoilage Found in Various Actual Losses.

CHAPTER XIII.
TOMATOES 398

Character of Tomatoes Raised in Different Localities, Method
of Canning, Cold Packed Tomatoes, Sour Tomatoes Due to
Souring Before the Sterilizing Process; the Cause and Rem-
edy, An Attempt to Pack Tomatoes in a Vacuum Jar, with-
out Sterilization; Cause of the Spoilage, Bacteria the Cause
of Tomato Black-rot Disease, Uneven Temperature in the
Process, Resulting in Loss.

CHAPTER XIV.
CORN 418

A Short Historical Sketch, The Canning of Corn, Suggestions
for Canning and Processing, Cause of Sour Corn, Labora-
tory Work on Spoilage Cases, Spoilage Due to Poor Tin
Plate, Spoilage Due to Imperfect Circulation in the Process,
Bacteria Which Cause Souring of Corn, Insufficient Sterili-
zation and Its Results, Discoloration of Corn Due to Prod-
ucts Elaborated by Bacteria; Other Causes, Method of Sep-
arating Sour Corn from Good, Method of Determining
Cause of Spoilage, whether Leaks or Insufficient Sterili-
zation.

PREFACE

THERE are many valuable works written on the general
subject of bacteriology, but nearly all such text-books
apply the science either directly or indirectly to the field
of medicine and surgery. Few authors have given any
considerable space to the study of non-pathogenic bacteria, and
very little attempt has been made to describe these species, beyond
a few typical forms mentioned by the old authors.

While the pathogenic bacteria are occasionally found associated
with the spoilage of food products, the non-pathogenic bacteria are
far more common. Some of the pathogenic bacteria produce pto-
maines and toxins in various food products, having gained entrance
through contamination with diseased persons and animals, but these
cases are extremely rare, owing to the rigid inspection of such
products as are most liable to infection. Putrefactive bacteria are
more commonly active agents in the production of ptomaines.

In this work we have endeavored to outline a course of study
in bacteriology which will be particularly useful to the manufac-
turer and the student of food products. The causes of spoilage are
defined, and the first volume is designed particularly to enable the
student to gain a general knowledge of bacteriology which may be
applied directly to solving problems of spoilage.

In the general plan have been introduced various well-known
species of bacteria for comparative study, because the descriptions
are given fully in nearly all text-books and the beginner will be
better fitted for isolating and studying new species after he has com-
pleted a study of the well-known species.

There has been no attempt to classify or name many of the
new species which were found associated with food spoilage, but
the author has been satisfied to describe the action of these species
on various food substances and has endeavored to ascertain the heat-
resisting power of various spores.

The first volume of this work is designed especially to assist
the student in a laboratory course in bacteriology applied to the
manufacture of food products, particularly Canning and Preserv-
ing. The half-tones introduced as illustrations were made from
photomicrographs taken by the author from specimens, stained and
mounted, which were either isolated directly from spoiled food
products or obtained through the courtesy of co-workers.

Several cultures of pathogenic bacteria were kindly furnished
by Dr. P. G. Novy of the University of Michigan, and these were

8 PREFACE

stained, mounted and photomicrographed for illustrations in this
book.

Chemical methods of analysis have been introduced for the
benefit of the student. Some of these tests are very useful in the
study of the products of fermentation and putrefaction. Other
tests are given for the detection of adulterations and preservatives,
all necessary for the study of food products.

In the beginning is a description of the microscope, lenses, ap-
paratus, etc., employed in different parts of the work, together with
a complete table of reagents used in the various preparations and
chemical tests.

Then follows the description and classification of bacteria and
methods of cultivating and staining. The method given for stain-
ing flagella is that employed by the author, with success. The
various forms of decomposition are carefully studied, the last of
which is the study of Putrefactive and Pathogenic organisms and
the poisonous products elaborated by them.

Sterilization has been carefully studied in all its bearings, in-
cluding Cleanly Methods of Manufacture and the Disposition of
Waste Material.

Considerable space is devoted to the subject of Preservatives ;
their natural origin ; their formation in canned goods during sterili-
zation. This subject has been studied by the author and his assis-
tants by feeding various animals stated daily amounts in their food
for different periods of time. The feeding terms, weights and path-
ological effects on the internal organs, are faithfully described. Var-
ious theories of physicians and authorities of the harmful effect of
these substances and their effect on processes of digestion have been
analyzed. Many of these theories have been completely upset by
actual tests and by force of argument. Throughout the whole
subject, the author has been faithful to facts as he found them, and
mere theories without the support of actual experiments and proofs
have been criticised.

Whatever may be true as to the effect of at least two preser-
vatives upon the human organism, no proofs of their harmfulness
have been produced, the preservatives studied in this connection are
Salicylic and Benzoic Acids.

So far as I know, no person has come forward with the state-
ment that he has ever been harmed in the least by eating them in
table luxuries. The fact that thousands of tons of these two pre-
servatives have been used by people who were under actual observa-
tion of the manufacturers, and the fact that no experiments with
animals have produced pathological changes, seems to indicate that
much of the hue and cry against them is not well founded.

PREFACE 9

Methods are given for extracting varous preservatives; also
artificial sweeteners; also Miguel's table of Antiseptics and their
value.

Artificial colors are not approved, and methods for detecting
them are given.

The last part of this volume is taken up with the study of the
canning of peas, tomatoes and corn. For twenty years the author
has had practical experience in canning and preserving, having had
charge of these departments for two of the largest houses in Ameri-
ca, so that the practical and the scientific knowledge of his subject
are brought closely together.

Considerable space has been devoted to the results obtained by
bacteriological and chemical analyses of various spoilage cases to-
gether with suggestions made to correct imperfect methods.

Some laboratory work on tin plate is reproduced. The author
has endeavored to show the action of fruits and vegetables on tin
plate. Quantitative analyses of new tin plate were made, and the
half-tones illustrate the imperfections as they appear on the ordinary
plate used for canning purposes.

While this volume does not take in the whole list of canned
and manufactured food products, in another valume the data at
hand and the results obtained from the investigation conducted dur-
ing the coming year will be published.

EDWARD W. DUCKWATJ..
Aspinwall. Pa., Sept. i, 1005.

MICROSCOPE

Canning and Preserving of Food
Products with Bacteriolo-
gical Technique

CHAPTER I.

The Laboratory and its Equipment

The Laboratory and Its Equipment. Apparatus Used in a
Bacteriological and Food Laboratory. Description of Lenses.
Table of Reagents.

THE MICROSCOPE.

THH MICROSCOPE is the most useful instrument needed for
this work, and its selection is important in order to get the best pos-
sible combination of good qualities. No. 10 stand, objectives, and
other attachments made by the Spencer Lens Company, of Buffalo,
N. Y., give excellent satisfaction. The microscope requires care-
ful attention ; it should always be kept in a tidy condition, and it is
quite necessary to know how to take care of the instrument in order
that its delicate parts may not be injured. The stand shown in the
cut has a handle, by means of which it may be carried, but most mi-
croscopes do not have this convenience and they must be lifted by the
pillar below the level of the stage, and never by the fine adjustment
tube or by the barrel. The lacquer of a microscope is injured by
finger marks and should not be touched. Finger marks may be re-
moved by breathing on the parts and gently rubbing with chamois
skin. No chemical, such as alcohol or xylol, should be used to re-
move the marks, because it may remove the lacquer also. The mi-
croscope is provided with milled parts, which are the only parts to be
handled when working.

The stage of the microscope should be kept clean and free from
water. During the examination of live cultures of bacteria it may
happen that some of the culture \vill get on the stage. It should be
carefully removed with a rag moistened with bichloride of mercury
solution.

OBJECTIVES.

The objectives are of two kinds, the dry and the oil immersion.
The dry objectives should be kept clean with dry lens paper; they
should never be allowed to touch oil, water or other substances.
The oil immersion lens is very delicate and easily injured. It should

CANNING AND PRESERVING OF FOOD PRODUCTS.

never be used dry, but always with a drop of cedar oil, and in the
manipulation it should never be forced down against the glass slide
or cover glass. Each evening after work the cedar oil should be re-
moved from this objective by means of lens paper, moistened with
xylol and dried with soft linen or lens paper. Alcohol or other
chemicals should never be used for fear of dissolving the cement
which holds the lens.

STANDS.

The selection of a stand is important, and while it may not be
expensive it should be strong and firm in all its bearings. If pho-
tomicrographs are to be taken, the stability of the stand must be

1. Cone, fine adjustment

first-class. The fine adjustment is important. One cannot realize
this until he begins to take photomicrographs. Many of the fine
adjustment schemes are very unreliable and are easily jarred out of
focus, particularly when the microscope is in a horizontal position.
There is a new fine adjustment which is operated by a cone. This
is so sensitive that the definitions of the reading drum, mark a ver-
tical movement of the tube of 0.002 millimeters. This is a great
advantage and is appreciated by the operator when making photomi-
crographs.

THE LABORATORY AND ITS EQUIPMENT.
MECHANICAL STAGE.

A MECHANICAL STAGE is very useful and almost indis-
pensable. The one shown in the cut gives an extended lateral move-

Fig. 2. Mechanical Stage

ment and the verniers are graded to read o.i m. m., and are placed
closely together so as to be read at a glance. The mechanical stage
has the advantage of holding in a steady position a particularly in-
teresting view. It is also valuable in searching the field, which can
be done systematically and with great precision.

OBJECTIVES.

OBJECTIVES are of two kinds, the dry and the oil. The
dry objectives are seldom made in powers higher than y$ inch. For
fine work, the apochromatic objectives are preferable to any others
on account of their greatly superior correction of spherical and
chromatic aberrations, which gives fine definition. The resolving
power is also greater than the achromatic on account of their higher
numerical aperture, but for ordinary work the achromatic objectives
answer very well.

THE LABORATORY AND ITS EQUIPMENT.

MICROMETER EYEPIECE.

For measuring objects under the objective it is advisable to
use both the micrometer eyepiece and stage micrometer.

Fig. 3. Spencer Micrometer Eyepiece

DESCRIPTION OF LENSES.

Lenses are of two kinds, simple and compound; the former
is generally a single lens. A simple microscope is therefore a
simple lens. The rays of light come directly from the object to
the eye and a Virtual Image is produced. (See figure 4, by Carpen-
ter.) This illustrates the simple microscope.

Fig. 4. Virtual Image, Simple Microscope (Carpenter)

The object is placed between the focus and the lens. This
figure also illustrates the action of the eyepiece in the compound
microscope. If the object is placed beyond the principal focus (p)
a real image results, as is shown in figure 5. This illustrates the
action of the objective in the compound microscope. In the com-
pound miscroscope there are two sets of lenses, the eyepiece and
the objective; the latter is nearest the object and produces a real

CANNING AND PRESERVING OF FOOD PRODUCTS.

Fig. 5. Real Image (Carpenter)

image, as shown in figure. The image, however, is inverted and
reversed; the light is inside the principal focus of the eyepiece and
rays of light leave it if they come from a real object. The image

Fig. 6. Principle of a Compound Microscope (Carpenter)

F Object in focus. O Objective with diaphragm. AB Real image of F, in the opening of the diaphragm;
above this is a compensating ocular which magnifies the real image AB, this forming the virtual image CD

16 CANNING AND PRESERVING OP FOOD PRODUCTS.

lying inside of the principal focus becomes magnified by the eye-
piece (e) and the Virtual Image (c d) is produced.

Roger Bacon, an English monk, is said to have been the first
man to recognize the peculiar properties of a lens, in 1276. The
simple lens was used in the construction of spectacles. In the
seventeenth century the microscope was perfected sufficiently to
discern bacteria. Galileo made a compound microscope in the year
1610, and a cut of this microscope is shown, by Carpenter. This
microscope contained a single lens for an objective and a single
lens for an eyepiece. The rays from the single lens do not meet
in the same plane and spherical aberration results. The rays of
light are also decomposed in a simple lens, which acts as a prism;
the violet is bent most and is brought to a focus at a different
point from the red ray, which is bent the least. A fringe of colors
results, and this is designated as "chromatic aberration". The
spherical chromatic aberrations are corrected in the best instru-
ments now made by means of diaphragms and stops and combina-
tions of different kinds of glass. The chromatic aberration is fair-
ly well corrected by the combination of the two glasses, Crown
and Flint, and the objectives made from this combination are called
Achromatic. Still, in the achromatic objective there is not absolute
freedom from color. Even if some of the rays are neutralized,
another will remain, and a certain amount of color will show in
the image in the achromatic objective. This is designated as "sec-
ondary spectrum." In order to overcome this color, Abbe and
Zeiss in 1889, prepared special kinds of glass, the so-called "borate"
and "phosphate" glass, and this combination in objectives was
designated as "apochromatic." Fluorite is also used in some apo-
chromatics and the secondary spectrum is thus corrected. This
correction is disturbed somewhat by the cover-glass ; which re-
fracts the peripheral rays as they enter the objective and they seem
to come from a point nearer the objective than do the central rays.
In order to overcome this the objectives are made "under-correct-
ed," so that both points are focused at once. In order to get uni-
form results it is well to use cover-glasses of uniform thickness for
the oil immersion objectives.

The most important part of the microscope, therefore, is the
objective, and great care should be exercised in making a selection
in order to get the best results. While good magnifying power
is always desirable, it is of less value than the defining, resolving
and penetrating power. A proper magnifying power is necessary,
and it is customary to speak of an objective as a 2 /$, J^, %, %,
1-12, etc. Some makers use these figures, others use letters, and
some designate the magnifying power by millimeters. Every ob-
jective has what is called an initial magnification, and this initial
magnification is multiplied by the magnifying power of the eye-

THE LABORATORY AND ITS EQUIPMENT. 17

piece used. For instance, if the initial magnifying of a 1-12 ob-
jective is 125, when a No. 8 eyepiece is used, the magnification
will be 1,000 diameters. Magnification is always meant as linear
in scientific work, magnification being expressed as so many di-
ameters. For instance, if a magnification is expressed as 1,000
diameters, the superficial area magnification would be 1,000,000.

THE DEFINING POWER.

It is difficult to secure perfect flatness of field. This is over-
come to some extent by compensating eyepieces. Flatness of field
is very essential in making photomicrographs. Probably the most
important qualities of the microscope are its resolving and pene-
trating power. These are the qualities which show up the fine
markings and delicate structures. These qualities have no refer-
ence to the magnifying power. The light which enters the ob-
jective has much to do with its resolving power.

Fig. 7

Arrangement of Lenses in a 2 millimeter or T V Oil Immersion Objective (Carpenter)

A Angle of Aperture

The light which enters the objective is included between the
extreme rays, and an angle is formed by the extreme rays with
the object in focus, and this angle is known as the "angle of aper-
ture," shown by (a) in Fig. 7. Fig. 7 shows the system of lenses
as they are arranged in the oil immersion objective. On account
of the number of lenses employed, the light becomes very faint, and
it is therefore necessary to admit as much light as possible. The
improvement of an oil immersion lens over a dry objective is clue
to the fact that the light passing from the object in focus into the
cover-glass is somewhat refracted, and unless it is collected again
much of it is lost. Amici introduced the water immersion objec-
tive. This was an improvement over the dry objective from the
fact that water would collect the rays of light fairly well, but in
1878 Stephenson suggested cedar oil, which has the same index of
refraction as crown glass, and this has been in use ever since. A

CANNING AND PRESERVING OF FOOD PRODUCTS.

high numerical aperture is then most valuable and objectives thus
constructed are the most expensive.

The penetrating power of an objective depends upon its ability
to show up objects in different planes. It is more highly perfected
in the lower powers and there is still room for great improvement.
In the examination of molds every worker is somewhat handicap-
ped on account of improper penetrability.

ABBE CONDENSER.

A most important accessory to the microscope is the Abbe
condenser. There are two special makes, the chromatic and the
achromatic. The first is suitable for ordinary work, but for photo-
micrography the achromatic is almost indispensable. Fig. 8 shows
a condenser of special construction, which can be swung out. Two
diaphragms ordinarily go with it, one above and one below, and

Fig. 8. Abbe Condenser

in addition to these there is a special arrangement made for hold-
ing the polariscope and other accessories for special illumination.
The mirror under the Abbe condenser is plain on one side and
concave on the other, the concave side being used to illuminate
specimens in a living state, and the light is regulated with the
iris diaphragm. The direct rays of the sun should never be used.
Some writers prefer the light from a white cloud, but more uni-

THE LABORATORY AND ITS EQUIPMENT. 18

form results are obtained from the Welsbach light. After one be-
comes accustomed to this light it becomes easier to make compara-
tive study. For photomicrography the electric light is frequently
employed, but the acetylene light is better in every respect, because
the details are more clearly brought out.

PHOTOMICROGRAPHIC CAMERA.

This need not be an expensive apparatus. The one shown in
Plate 2 is well suited for the work, because the camera and opti-

Plate 2. Photomicrographic Camera

cal bench are solidly and conveniently held by a single support, giv-
ing them stability and perfect alignment without the risk of its
disturbance.

In making good photomicrographs there are several points
which must be carefully borne in mind in order to secure good
results: First, a good slide preparation; second, a good miscro-
scope stand, provided with objectives and eyepieces, having the

20 CANNING AND PRESERVING OP FOOD PRODUCTS.

qualities described under the head of "The Microscope;" a proper
screen, acetylene light, and first-class isochromatic or orthochro-
matic plates. The development of the plates and the printing are
all well understood by anyone familiar with photography.

INCUBATOR.
The one shown in the cut is admirably adapted for the cultiva-

Fig. 9. Incubator

tion of bacteria. To this must be attached a thermostat, which
can be regulated, so that any desired temperature may be main-
tained constantly. This apparatus is very necessary in the cultiva-
tion of a great variety of bacteria and the usual temperature em-
ployed is 98F., although for special organisms a room tempera-
ture is better. The incubator should be provided with a glass door

THE LABORATORY AND ITS EQUIPMENT. 21

so that cultures may be observed without opening excepting when
it is absolutely necessary. Heat is supplied by the Koch's safety
burner, which turns off the gas supply automatically in case of ac-
cident. For testing canned goods to determine if the sterilizing
process has been sufficient the incubator is almost indispensable.

THE AUTOCIvAV.

This apparatus resembles in many respects the ordinary steam
retort used in every cannery. A little water covers the bottom
and steam is generated by means of a triple Bunsen burner, so that
any desired temperature can be raised. As shown by the cut the

Fig. 10

top is arranged so that it can be clamped down, and a safety valve,
thermometer and steam gauge are attached to the top so that they
may be easily seen. This apparatus is used for sterilization of all
culture media, and such media as are not injured by high tem-
peratures are sterilized in one operation, where four or five opera-
tions are required in the laboratory not equipped with the auto-
clav. It affords an excellent means of determining the heat re-
sisting power of various spores.

22 CANNING AND PRESERVING OF FOOD PRODUCTS.

THE CENTRIFUGE.

Fig. 11

This apparatus is used in the laboratory for various purposes.
It is almost indispensable for breaking up emulsions formed by
solvents in determining the presence of preservatives in food prod-
ucts. It is also useful in separating blood serum from the corpus-
cles. It is useful in precipitating the tubercule bacilli from sputum
made into emulsions. It is used frequently in determining the
presence of fat in milk, cream, cheese and other substances.

DISTILLING APPARATUS.

Fig. 12. Distilling Apparatus

This apparatus is necessary for distilling water and other sub-
stances where a clear solution is desired. It is made of heavy
copper, is lined with movable head., and the condensing worm is
made of pure block tin.

THE LABORATORY AND ITS EQUIPMENT. 23

ANALYTICAL SCALES.

Fig. 13. Balances

These balances are graduated in 100 divisions for i m.m. and
show the sensibility of 1/200 m. g. The beam and its hangings
are of pure aluminum ; the bearings are of agate with agate knives.
These balances are used in fine analytical work, such as the deter-
mination of the amount of tin used on tin plate and the weighing
of minute quantities of any chemical. Such a balance is indispen-
sable in a well-equipped laboratory.

WATER BATH.

Fig. 14. Water Bath

This apparatus is employed for evaporating substances which

CANNING AND PRESERVING OF FOOD PRODUCTS.

are affected by more intense heat. There is probably no apparatus
in the laboratory which is employed more constantly than this.

PARAPFINE BATH.

Fig. 15. Paraffine Bath

This bath is very useful for high temperatures and is the one
employed for the conversion of saccharin into salicylic acid. It is
very useful where temperatures running- from 120 to 25OC, are
required.

FORCEPS.

Fig. 16. Cornet Forceps

Fig. 17. Novy Forceps

THE LABORATORY AND ITS EQUIPMENT. 25

The two cuts show the character of the forceps used generally
in bacteriological work. The Novy forceps are convenient for
handling cover-glasses, while the Cornet are large and firm and
are so constructed that they will hold stains in fluid form on the
cover-glass, so that they will not run down underneath nor onto
the forceps.

THE MICROTOME.

BUFFALO. N. Y.

Plate 3. Microtome

CANNING AND PRESERVING OF FOOD PRODUCTS.

This apparatus is used for making sections of the internal
organs of such animals as Guinea pigs, rabbits, etc., shown in
chapter on preservatives. The feed is controlled by an adjustable
cam having a scale marked with a number of teeth, providing for
any thickness of section from one up to twenty-five microns or
more, and is absolutely reliable. The sections which are photo-
graphed in this volume were cut from one to two microns in thick-
ness. For bacteriological" and pathological work this apparatus is
indispensable.

List of Apparatus and Chemicals

1 Agar apparatus.

1 Acetylene gas generator and burn-
ers.

1 Anaerobic culture apparatus.
1 Animal Holder.
3 Asbestos pads.
1 Aspirator.
1 Autoclav.
1 Nest of Beakers.

1 Blast lamp, bottles, various sizes,
colored glass.

6 Boxes slides for microscope.
12 Boxes for test tube cultures.

2 Burettes.. 50 c. c.

2 Burettes, 100 c. c.
2 Burette stands.

1 Buto-refractor.

2 Burners, Bunsen.

1 Centrifuge, Babcock's.

1 Chamberlain filter.

Cheesecloth.

1 Colony counter.

1 Copper soldering iron.

1 Corks, assorted sizes.

1 Cotton roll, absorbent.

2 ozs. Cover-glasses, No. 1.
1 Crucible.

1 Cylinder, 25 c. c. graduated.
1 Cylinder, 50 c. c. graduated.
1 Cylinder, 100 c. c. graduated.
1 Cylinder, 500 c. c. graduated.
1 Cylinder, 1000 c. c. graduated.
1 Dessicator.
1 Disinfecting jar.

1 Distilling apparatus.

4 Enameled pans, nested.

12 Esmarch dishes.

100 Filter paper, circles, 20 cm.

100 Filter paper, circles, 32 cm.

100 Filter paper, circles, 15 cm.

1 Square yard Flannel.

G Flasks, Erlemeyer vacuum.
12 Flasks, Florentine, 500 c. c.

2 Funnels, large.
2 Funnels, 15 cm.
2 Forceps, Novy.

6 Forceps, Cornet.

2 Glass stiring rods.

6 Glass slides, hollow ground.

500 g. Glass tubing, 4mm. diam.

500 g. Glass tubing, 6mm. diam.

500 g. Glass tubing, 8mm. diam.

500 g. Glass tubing, 22mm. diam.

1 Hot pan.

1 Hydrogen generator, Kipp's.

1 Hydrogen sulphide generator.

1 Incubator, large, complete.

Labels, slide, jar and bottle.

1 Magnifier, simple lens.

1 Micrometer, cross-wire ocular.

1 Micrometer eyepiece.

1 Micrometer, stage.

1 Microscope, Spencer, No. 10 stand.

1 Mechanical stage, Spencer.

4 Eyepieces, 4, 6, 9, 12, compensating.

4 Objectives, 2-3, 1-6, 1-12, 1-16,

apochromatic.
1 Abbe condenser, achromatic

THE LABORATORY AND ITS EQUIPMENT.

1 Triple nose piece.

1 Bull's eye, 3 in.

1 Microtome, Spencer.

1 Paraffine bath.

1 gross Petri-dishes, various sizes.

1 Photomicrograph camera, Spencer.

6 Pipettes, various sizes.

3 Platinum wires in glass rods.

1 Polariscope.

6 Porcelain dishes, nested.
3 Knives, peeling.

2 Retort stands.

Rubber stoppers, various sizes.
1 Sand bath.

1 Scissors, 14cm.

2 Separatory funnels.
1 Shears, tin.

1 Syringe, 5 c. c. inoculating.
200 Test tubes, 12 X 125 mm.
200 Test tubes, 15 X 150mm.
24 Test tubes, 20 X 150mm.

2 Test tube brushes for cleaning.
2 Thermometers, clinical.

1 Thermometer for retort.

1 Thermometer for paraffine bath.

2 Thermo-regulators.
2 Tripods.

1 Wash bottle.

6 Watch glasses, 5 cm.

1 Water bath.

2 Wax pencils, blue and yellow.

3 Wire baskets, medium.
6 Wire baskets, small.

6 Wire cages for animals.
3 Wire gauze.

CHEMICALS AND SUPPLIES

10 grams. Acetic acid, glacial.

100 grams Agar agar.

1000 grams Alcohol, absolute.

1000 grams Ammonium hydrate.

10 grams Benzoic acid.

100 grams Benzoate of sodium.

10 grams Boracic acid.

10 grams Borax.

100 grams Carbolic acid.

50 grams Celloidin.

3000 grams Chloroform.

100 grams Collodium.

10 grams Eosin.

3000 grams Ether.

50 grams Ferric tartrate.

50 grams Ferrous sulphate.

25 grams Fuchsine (not the acid).

250 grams Gelatin.

10 grams Gentian violet.

200 grams Glucose.

100 grams Glycerin.

50 grams Hematoxylin, Delifield's.

2500 grams Hydrochloric acid.

50 grams lodin, resublimed.

30 grams Lactose.

50 grams Litmus.

Litmus paper, red and yellow.

100 grams Mercuric bichlorid.

15 grams Methylene blue.

1000 grams Nitric acid.

50 grams Cedar oil.

50 grams Clove oil.

3000 grams Paraffin.

200 grams Pepton, Witte's.

200 grams Potassium bichromate.

200 grams Potassium iodide.

5 grams Potassium ferrocyanide.

100 grams Pyrogallic acid.

100 grams Salicylic acid.

500 'grams Salt.

200 grams Sealing wax.

200 grams Sodium carbonate.

500 grams Sodium hydrate.

500 grams Solder.

500 grams Steel filings.

2500 grams Sulphuric acid.

50 grams Tannic acid.

500 grams Tin foil.

50 grams Turpentine.

100 grams Vaseline.

500 grams Xylol.

3000 Zinc, granulated.

500 grams Zinc chlorid.

20 grams Canada balsam in tube.

100 pounds Carbide in drum.

CANNING AND PRESERVING OP FOOD PRODUCTS.

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BACTERIA. DESCRIPTION AND CLASSIFICATION. 33

CHAPTER II.

Bacteria Description and Classification

Spore Formation. Nature of Bacteria. Influence of Electricity
on Bacteria. Influence of Various Temperatures. Influence
of Light. Motility. Chromogenic Bacteria. Bacterial Prod-
ucts. Slime, Ropiness, Etc.

Bacteria belong to the lower vegetable kingdom and are not
properly named germs or microbes, which terms embrace a larger
meaning including animalcules and lower insect life. In 1683
Leeuwenhoek made the discovery of bacteria while examining the
scraping of the teeth, and for nearly two hundred years bacteria
were thought to be animal life. In 1875, several investigators,
Cohn, Xaegeli and others, settled the fact that they belonged to
the vegetable kingdom, principally on account of their resemblance
to the algae in their manner of reproduction, growth and multipli-
cation. The distinction between these low vegetable forms and the
lowest forms of animal life is not so easily determined as we might
suppose, for the reason that there are so many unknown facts
concerning both, which science up to this time has not been able
to make clear. Although the microscope has been brought to a
degree of perfection hardly to be improved, there are still forms of
life which are beyond its power. It was thought until recently
that bacteria were the smallest forms of life, but the researches of
Dr. Koch and others have brought to light that there are still
smaller organisms which are the probable causes of maladies such
as Foot and Mouth disease, Horse Sickness and Rinderpest.

However, there are so many characteristics of plant life in
bacteria, that they are properly assigned to the vegetable kingdom.
They resemble in many ways the higher forms of microscopical
plant life, viz.: molds and yeasts which are classed as fungi, but
in size they are very much smaller. Bacteria multiply by fission
or division, from which characteristic they are termed Schizomy-
cetes. The division takes place by a lengthening, when a constric-
tion takes place thus :

CD OD

3 */

Fig. 18

34 CANNING AND PRESERVING OF FOOD PRODUCTS.

The yeasts multiply by budding as also do some of the molds
under certain conditions. The yeasts are termed Blastomycetes.
The molds naturally grow in a thread-like manner, spreading out
and sending up fine hair-like tufts or hyphae, hence they are termed
Hyhomycetes. The classification of bacteria is not complete. There
are various forms which are taken as types, but changes often take
place due to the character of the substances in which they are found,
which cause one class to appear very like another class. The classi-
fication as we have it is based upon the form, size, motility, manner
of dividing, formation of spores, the presence of flagella or hair-
like propellers, their ability to resist high temperatures, the enzymes
or products resulting from their growth, the colors formed by cer-
tain kinds, the flavor produced by others, their manner of growth
on certain artificial media or food specially prepared for them and
many other ways, but first they can be divided into three classes
with reference to external appearance.

ooo
c oo-

Fig. 19

A Micrococcus or single round cells
B Bacillus or rod form.
C - Spirillum or spiral form.

A very short bacillus is often termed a bacterium. The spirilla
or curved forms are often joined together to form a spiral and
were called vibrios in Pasteur's time. There are very great differ-
ences in sizes of bacilli, some being quite short and thick, others
very long and delicate, and vice versa. Some have square ends.
others are rounded.

There are many different kinds of bacteria which resemble
each other in all that the microscope will reveal, and their identifi-
cation depends upon their behavior under various conditions. It
is a fact that the identification of very few bacteria can be deter-
mined by the microscope alone, but after observing a certain form
in many conditions, its identity may be pretty clearly determined.
Changes in temperature while growing; cultivations in acid or al-
kaline media; cultivations in fluid and on solid media may give
rise to varied shapes, colors and products, which may be noted
and the character of the organism established.

The action of chemicals, dyes, salt and sugar solutions may
cause what is known as plasmolysis, which is a shrinking of the
cell membrane and the granulation of the protoplasm or contents
of the cell. Sometimes the cell membrane disappears so that the
bacillus appears as a row of little round balls.

BACTERIA. DESCRIPTION AND CLASSIFICATION.

One fact has been established which is interesting to the stu-
dent of evolution, i. e., one kind of bacillus never develops into
another kind. Like springs from like, just as in the higher forms
of life. If there are hybrids among them it has not been proven,
but there is some evidence of this in disease organisms, particularly
in mammal and avian tubercule bacilli. Bacteria are known to
change completely in some respects, but their identity is not lost.
We have seen certain species which ordinarily do not liquefy gela-
tin, suddenly divide into two classes, one of which will ever after-
ward liquefy gelatin, and vice versa. Proteus Zenkeri is probably
a type of this species.

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Fig. 20

Illustrations of the manifold variety in size and form of different bacteria.
Except A4 and A5 all the above illustrations are representations of equally magni-
fied bacteria from a single drop of putrescent blood (after P. Baumgarten) x 950.

A-l Cocci (micrococcus) of various sizes.

2 Diplococci of various sizes.

3 Streptococci of various sizes.

4 Micrococcus tetragonus (from pure culture) magnified 950.

5 Sarcina ventriculi, magnified 700

6 Staphylococci.

B-l, 2, 4 Separate long rods of various lengths and breadths.
3 Short rods, partly of biscuit form.
5 Chains composed of either short or long rods.
H Long threads.

36 CANNING AND PRESERVING OP FOOD PRODUCTS.

The illustration in Fig. 20 gives a good idea of the appearance
of different types as they appear under the microscope.

The manner of vegetation or multiplication is as follows :

The Coccus vegetates by becoming longer, constriction follows
and finally complete separation.

When they remain united in twos they are named Diplococci.

When they divide in two directions to make fours, they are
named Tetragoni.

When they remain united forming chains they are named
Streptococci.

When they form bunches resembling grapes they are named
Staphylococci.

When they divide in three directions making* eight cells and
remain united in bundles they are named Sarcinci.

The rod forms may lengthen, divide and separate, or may
form pairs or chains resembling sausages. These chains are easily
broken up by agitation so that they appear more frequently in the
field of view under the microscope in all three forms.

LIFE HISTORY OF BACTERIA.

Bacteria are present almost everywhere, in the ground, injthe
air, clinging to dust and floating matter, and in water. They~find
their way into living bodies and plants and are most numerous
,where there is decomposition of organic matter. The air in mid-
ocean is free from them, because all suspended particles are de-
posited in the water and the air is washed until it is pure. The air
at high altitudes is almost free from bacteria and the soil at the
depth of twelve feet also. Water from artesian wells is almost
free, and whatever contamination it has is clue to the deposit of
germ life from the surface. The air that is exhaled from the
lungs is free; no matter how many thousands of bacteria are in-
haled, they are ca-ught by the hairs and mucous in the air passages
and cast out or eventually destroyed, except where disease is con-
tracted. The origin of bacteria is not known, but is shrouded in
the mystery of creation. There is evidence that new species are
created, although it cannot be stated as a positive fact. New dis
eases make their appearance and cases of spoilage in food products
occur which seem to be new. The great majority of bacteria are
harmless to man, indeed are very necessary and indispensable as
decomposing agents of dead organic matter. Through their in-
strumentality, obnoxious accumulations are reduced to elementary
forms capable of building up new life, both animal and vegetable.

There is another class called pathogenic bacteria which are in-__
strumental in the destruction of living animals, including man. This
class is to the bacterial flora what the poisonous plants and weeds
are to the higher forms in the vegetable kingdom, and like these

BACTERIA. DESCRIPTION AND CLASSIFICATION. 37

are in the minority. Bacteria, as we have stated, are almost uni-
versally distributed, but are not always in the full vegetating form
as we see them under the microscope. They become dried up, or
in spore form are wafted through the air or are carried by water
until they are lodged upon certain kinds of organic material which
furnish them the necessary elements for growth, which is termed
vegetation. This is a multiplication which continues until certain
conditions arise, such as change of temperature or chemical com-
position, due to their own action or the products formed by other
kinds of bacteria vegetating at the same time with them, or by con-
ditions arising from natural causes, when they either perish or
pass into a resting or dormant state. The resting state is charac-
terized by a drying up of the cell membrane or the formation of
spores. While it is probable that nearly all bacteria give rise to
spores of some kind, this has not been demonstrated as a fact, be-
cause the conditions under which we cultivate them for study and
observation are not always as favorable as the conditions under
which they grow naturally; then, again, the extreme minuteness of
many forms prevents the close examination necessary to establish a
complete life history. There is evidence that spore formation may
go on in a field far beyond the power of our best microscopes.
The phenomenon of spore formation is observed, however, in the
life history of a large number of bacteria, and the formation and
liberation of spores in many cases can be watched with interest in
the hanging drop cultures. The formation of spores is not always |
due to the causes assigned above, viz., the exhausting of the food
supply, etc., for it frequently occurs when the nourishment is most
favorable for natural vegetation or multiplication. We must make
a clear distinction between spore formation and vegetation, the
spores correspond to the seed in higher plant life and are formed
for the perpetuation of the species, while the vegetation is a multi-
plication, not by seed formation but by division, and may go on
almost indefinitely, if the bacteria are constantly transplanted into
fresh nutrient material. (There are exceptions to this however.)
The pathogenic bacteria do not naturally show spore formation,
because the living body supplies them constantly with fresh ma-
terial for multiplication. Some of the pathogenic bacteria when
grown artificially in the laboratory on nutrient media, do give
rise to spores, showing their relationship to the ordinary non-
pathogenic bacteria. Anthrax and Tetanus are examples of this \
kind.

Fig. 21. Sporulation

a First stage showing granules, b Incomplete spore, c Developed spore.

(After Novy.)

38 CANNING AND PRESERVING OF FOOD PRODUCTS.

Nearly all text-books speak of two kinds of spore formation,
viz., endospores and arthrospores, from a theory advanced by De
Bary. The endospore is always formed within the cell. The arth-
rospore formation is supposed to be a complete thickening of the

Plate 4. Anaerobic Pea Bacillus

Photomicrograph of the Spore-bearing rods of thfc Anaerobic Pea Bacillus found in a can of swelled peas
The spores are terminal and greatly resemble Bacillus tetanus. Magnified 1,000 diameters.

cell membrane which contracts so that the cell thus becomes a
spore. The arthrospore theory, however, is not well founded be-
cause the actual observance of this phenomenon is wanting. We
are only certain of endospore formation. The formation of spores
is thus observed : The whole bacillus is first seen as a colorless,
homogeneous cell, showing no bright spots. When it advances to
the state of spore formation, fine granules can be detected scat-
tered throughout the cell, some very small, others larger and ir-
regular, one bright spot continues to grow larger and brighter and
the other granules may probably be absorbed by it the bright
spot, at first irregular, now begins to assume definite shape, either
round or ellipsoidal, with a dark line forming around it which
seems to grow thicker, forming a wall which seems to enclose all
the contents or protoplasm of the cell, or the protoplasm may go
to build up the spore wall, which is probably the case. The old
cell is now merely a shell containing the spore and may soften and
disappear in the surrounding fluid, leaving the bright spore in a
free state. In some cases the cell remains together with the spore
and may not dissolve. This complete process may occupy several
days, but is often accomplished in a much shorter time.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 39

Ordinarily one spore develops within a single bacillus, but A.
Koch has mentioned that Bacillus Inflatus has two ; this is im-
probable. Not every bacillus gives rise to spores it sometimes is
observed that a whole chain of bacilli will be seen with spores ex-
cepting one or two which seem barren.

Fig. 22

Bacillus Inflatus a, b, e, cells of clostridium form one elongated cylindrical en-
dospore. c, d, f, g, cells with two spores of unequal size. Magnified 2,100.
(After A. Koch.) Spirillum Endoparagogicum b, vegetative cells, a, two cells,
one with two and the other with three endospores. (After Sorokin.) Bacillus
Tumescens Chain of seven cells, six of which have developed one spore each,
while the middle cell has remained barren. It is granular. XI, 100. (After A. Koch)

Plate 5

Photomicrograph of rods containing terminal spores, barren rods and free spores.

Spores develop in a certain position in the bacilli of the same
kind, which is a guide to the student for identification. When a
single spore develops in the end it is named a terminal spore, when
in the middle of the cell it is called a median spore, when in a posi-
tion between these two it is called an intermediate spore. During
spore formation the form of the mother cell may remain unchang-
ed, but more of swelling takes place at the point of spore forma-
tion, so that the bacillus represents a drum stick, club, or nail
head, if the spore is terminal and may resemble a spindle or lemon,
if the spore is median or intermediate, this form is designated as
a clostridium.

40 CANNING AND PRESERVING OP FOOD PRODUCTS.

The size of spores varies ; they are usually oval or ellipsoidal
I/A to 3/* in length (*/* =1/25,000 of an inch) by 5/* to i/* in breadth,
although we have reason to believe there are some very much
smaller.

Fig. 23

Vibrio Rugula Seven rods with a terminal spore. Magnified 1,020. Clostridium
Butyricum a, b, vegetative cells; d, beginning of spore formation; c, e, progress;
f, h, completion ; a, f, contain granular stained blue by iodine ; h, sustained by
iodine ; g, cell with two spores. X 1020. (After Prazmowski. )

As we have stated before, the formation of spores is the means
of perpetuating the species, consequently a number of bacteria are
known to give rise to spores whenever the conditions are such that
the bacilli cannot continue in the vegetating state. In order that
the spore may be able to live through great changes in tempera-
ture, the cell wall is thick and not easily penetrated by heat or dyes,
consequently in the ordinary staining methods, the spores present
their oil-like refractory appearance, while the surroundings are per-
fectly stained.

On account of the heat-resisting power of spores, the study of
this phenomenon is interesting to the canner. At one time it was
believed that the bacilli as well as the spores could be destroyed by
212 degrees P., steam heat, in fifteen minutes, and no less an au-
thority than Koch fell a victim to this theory, which E. von Es-
march overthrew. The spores of some bacteria were found to be
able to sustain life after continuous boiling for six to ten hours.
The same spores were destroyed, however, by a temperature of
250 degrees for fifteen minutes, steam heat directly applied. This
extreme heat-resisting power led some famous bacteriologists into
error. Prominent among them was Von Liebig, who built up a
theory of spontaneous generation, founding it on the life which
spontaneously destroyed certain infusions such as meat, milk and
hay, after all life (as he thought) had been killed by boiling heat.
Pasteur and Tynclall did not follow this theory, but labored to dis-
cover the cause of their failure to preserve certain infusions. After
numerous experiments they were able to state positively that there
were forms of life which could live through the boiling point; so
the system of discontinuous heating was discovered by Tyndall and

*The Greek letter m is an abbreviation for the Greek word micron, which
means small and is equivalent to W^TSO of an inch.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 41

this method of sterilization is still used to this day as a means of
sterilizing certain materials which are altered by the employment
of high temperatures.

The theory was built upon the fact that the tender, vegetating
forms of life were easily destroyed by temperatures as low as 160
degrees F., consequently after heating once the first day, Tyndall
allowed the infusions to cool, and stand long enough for the spores
to begin to develop into bacilli, when he again subjected them to a
second heating, and repeated the process three times, by which he
killed all, the spores having all started to germinate. While this
system is useful for the sterilization of some infusions, it cannot
be declared infallible, since only the aerobic bacteria (i. e., bacteria
which grow in the presence of air), would develop from their
spores during the intervals between the heatings. The spores of
the anaerobic bacteria would not germinate unless the process were
repeated in a condition where air was expelled. This would re-
quire a number of heatings, some after exposure to air for the
spores of aerobic bacteria to germinate and some after the exclu-
sion of air for the spores of the anaerobic bacteria to germinate.
For ordinary purposes, however, the temperature of 250 degrees
F. was found sufficient to destroy all life in material which was
not altered by the heat.

Under ordinary conditions, the spores of bacteria will live for
a number of years. Cold does not seem to destroy the spores
and only a few antiseptics will kill them. Pressure of great power
does not destroy them nor have electricity nor the X-rays proved
successful destructive agents. Radium has no devitalizing power,
as demonstrated by Prescott. Carbolic acid, bichloride of mercury,
and hydrocyanic acid will destroy them in a few minutes, but ordi-
nary antiseptics in such proportions as are commonly used for the
preserving of certain condiments, do not destroy the spores, but
produce conditions which are unfavorable for their vegetating into
full-grown bacilli.

THE SPORH IS THE LIFE SEED of any given species,
and if all moisture is absorbed from its surroundings, it will dry
up, the membrane around it will harden, and it may cling to dust
or floating particles in the air, and be wafted here and there by
currents of air until it falls into a substance suitable for its germi-
nation, or it may die, although it has been known to remain alive
and have power to germinate after many years of dormancy.

When it falls into a suitable medium for its germination, the
spore-wall softens and a considerable amount of moisture is ab-
sorbed, which results in the development of a living cell; this will
lengthen and divide, remain attached or become free, until the con-
ditions are reached for the cells to form spores again. Spores do

CANNING AND PRESERVING OF FOOD PRODUCTS.

not multiply, they simply furnish the life for one new cell, which
will multiply.

THE GERMINATION OP SPORES is different in many
cases, although it is probable that spores of a given bacillus always
germinate in the same manner. The observation of spores germi-
nating is a tedious proceeding, requiring much time and careful
preparation. It is usually observed in the hanging drop culture,
which is made by placing a drop of nutrient material on a cover-
glass and inoculating this with a species which has formed spores
in some other medium. The cover-glass is then inverted on a slide
with a hollow-ground cell in the center so that the drop will hang
without touching the glass, the cover-glass being sealed all around
by vaseline to prevent evaporation, thus :

Fig. 24. Hanging Drop Culture

H Hanging Drop.

C Cover glass over the cell.

V Vaseline holding cover glass over slide S.

The edge of the drop is found with the low power objective
first, and then a drop of cedar oil is placed on the top of the cover-
glass and the 1-12 oil immersion lens is brought down into focus.
The first sign of spore germination will be a glistening of the
spore, which will be seen to swell and lengthen, grow less bright,
antil a homogeneous cell is formed showing very little or no re-
fraction.

The germination is accomplished in several ways.

Probably the most common method of spore germination is
the growth of the bacillus from one end. The end appears to open
and the young cell pushes out in the long axis of the spore. An-
other method is the opening of the spore at the sides, when the
spore seems to split in halves, letting the young cell out in a right
angle to the long axis of the spore.

Another method is the opening of the spore wall on one side
through which the young cell emerges in a bent form, the middle
coming out first and then the ends, causing the young cell to look
like a magnet or horse-shoe.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 43

Another method of germination is the swelling of the spore
by a gradual elongation of the spore, which seems to absorb mois-
ture, increasing in protoplasm until a fully developed cell is born,
able to multiply in the regular manner.

= c

i I c 00 efS oo CO

I 6b

Fig. 25

A Lengthening of the spore.
B Bacillus growing out of the end of the spore.
C Bacillus growing out of the side of the spore.

D Bacillus growing out of the divided spore and in in horse shoe shape at
the side.

The study of spores is most interesting to the manufacturer
of food products, for the reason that they are very resistant to
heat, which is usually employed to sterilize all canned goods and
many other kinds of goods as well. There are some varieties of
spores which live through continuous boiling for five hours and
more, but are killed at 250 F. by directly applied steam heat, in
about fifteen minutes. Now, this heat must come directly onto the
spores, so the larger and denser the volume, the longer it takes to
heat it to the center. ' Various liquids, such as soups, are canned,
which convey the heat better than heavier materials, such as corn,
peas, meats, etc., and to destroy the spores of certain classes of
bacteria the temperature of 25oF. must reach the center of the
package and be maintained for about fifteen minutes. For experi-
mental tests, there are made especially for this purpose self-regis-
tering thermometers which fit into the can and remain in the center.
When the temperature reaches 250 F. the mercury does not drop
on cooling owing to a constriction in the tube which holds it
until it is shaken down by gentle tapping.

Valuable knowledge may be gained by the canner from per-
sonal experiment with this device in his sterilizing processes. By
noting how many minutes it requires to reach the proper tempera-
ture after the retort thermometer indicates the right temperature
on the outside, he can know just how long he must process his
goods to destroy the spores of such bacteria as are known to infest
the particular product which he is canning. The canner must first
study just what bacteria are continually present in the particular
products he is manufacturing; this is found out by cultivation on
nutrient media similar to those products. Later we will explain
how to make these cultivations so that all kinds of germs may be
isolated and identified, when grown by themselves, and experiments

44 CANNING AND PRESERVING OF FOOD PRODUCTS.

made by inoculating sterile cans and subjecting the bacteria to vari-
ous temperatures in order to learn their resisting power to heat,
etc.

NATURE OF BACTERIA.

COMPOSITION. Water makes up a large per cent, of the
composition of bacteria and is calculated to be from 60 to 85 per
cent. ; fats, from i to 40 per cent. ; proteins, 10 to 15 per cent. ; min-
eral compounds, I per cent. ; sometimes cellulose and granulose are
present, particularly in the carbohydrate species. All bacteria con-
tain one or more soluble ferments which are compounds capable
of producing fermentation, and are called enzymes. The class of
bacteria which produces diseases in man and animals produces
poisons called ptomaines and toxins, which may be extracted. From
the non-pathogenic bacteria also the enzymes may be extracted,
some of which are used in producing desired fermentations. Heat
usually destroys these enzymes as well as a great many toxins from
pathogenic bacteria.

The average composition of bacteria is estimated at 85 per
cent, water and 15 per cent, dry matter (by Kappes). The dry mat-
ter is made up as follows :

Per cent.

Etherial extract (fat, etc.) 4-8

Albumen 71.2

Ash . . 13.5

Undetermined matter io ? 5

There is a very large per cent, of nitrogen in bacteria, far more
than in the higher vegetable orders, and carbon enters largely in-
to the composition of the protoplasm. The bacterial cells are de-.
void of chlorophyll (the green coloring matter of the higher
vegetable kingdom) consequently, they cannot obtain the carbon,
as do the higher plants, from carbonic acid gas, but are dependent
upon carbon compounds. Sugar furnishes carbon, also other car-
bohydrates and fats, proteins, and likewise organic compounds, such
as glycerin, tartaric and lactic acids.

The nitrogen of the air cannot be utilized by bacteria (one
class excepted), consequently they are dependent upon nitrogenous
compounds for their supply. Animal and vegetable matter is al-
ways accessible, the proteins of which furnish the nitrogen. Chem-
ical compounds and acids can also be utilized.

The hydrogen is obtained from the same sources as the carbon
and nitrogen, but the oxygen may be obtained from the atmos-
phere or from compounds, according to the kinds of bacteria and
their environments.

Some bacteria thrive well in media which are acid; others
thrive better in alkaline media.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 45

The chemical composition of bacteria, therefore, depends to a
great extent upon the nature of the substance upon which they are
thriving. Certain bacteria may grow luxuriantly in an acid medium
such as tomatoes and fruit juices and may remain dormant or
die in an alkaline medium. Then, again, other kinds of, bacteria
which grow well on an alkaline medium will remain dormant or
die in an acid medium. To this class the majority of bacteria be-
long. This difference in the nature of bacteria will throw some
light on the different temperatures employed in sterilization, the
character of the bacteria being determined by the degree of acidity
of the material.

BACTERIA AND THEIR SUPPLY OF OXYGEN.

Many kinds of bacteria obtain the oxygen so necessary for the
process of multiplication from the air, and if the air is cut off they
either remain dormant or die these are called aerobic; others can-
not use the oxygen of the air, so they obtain their supply from or-
ganic compounds, such as the proteins and carbohydrates; these
are called anaerobic. There are others which accommodate them-
selves to whatever condition in which they may be placed, if aerobic
by nature they will still grow in an anaerobic state and are called
facultative anaerobes; or if anaerobic by nature and grow in an
aerobic state they are called facultative aerobes.

Nearly all bacteria found in improperly sterilized hermetically
sealed packages are either anaerobic or facultative anaerobic. This
latter class sometimes causes more violent fermentation when forc-
ed to grow in the absence of free oxygen than when growing nat-
urally; being deprived of free oxygen the tearing down of organic
compounds is accomplished with great rapidity to supply the re-
quired oxygen, while the actual multiplication is lessened. This
fact is interesting to canners, as it accounts for the rapid spoilage
of goods which have been improperly sterilized. Here the fermen-
tation is much more violent and rapid than in the packages where
there is a perceptible leak through which the oxygen from the air
passes. It is curious that sometimes the product will be found
perfectly sweet at the bottom of a can which has a large leak in
the top, while the whole surface is covered with molds, yeasts and
bacteria of various kinds. In this case the evolution of gas is not
as great as when the can is undergoing chemical changes in the
absence of atmospheric oxygen.

To the facultative anaerobes a large per cent, of losses in can-
ned goods is due. The anaerobic bacteria, however, cause spoilage
in many cases where the others are destroyed, because they belong-
to the soil and are spore -bear ing and have the power to withstand
very high temperatures and afterward develop. All anaerobes
known, except possibly one species, are bacilli, that is, rod-shaped.

46 CANNING AND PRESERVING OP POOD PRODUCTS.

Bacterium Phosphorescens, Fischer

PHOTOBACTERIUM PHOSPHORESCENS.

Origin. It is found on dead seafish, oysters, etc. Meat in butcher
shops may be contaminated from these.

Form. Short, thick bacillus, having rounded ends; almost a coccus
sometimes. Usually found in pairs, but may form threads; involution
forms soon develop.

Motility. It is not motile.

Sporulation. Has not been observed.

Anilin Dyes. Stain readily, as does also Gram's method.

Growth. The growth is moderately rapid. Cultures show a marked
bluish-green phosphorescence in the dark.

Gelatin Plates. The colonies are small, white and glistening, and
do not liquefy ; they have a sharp, irregular border ; are granular, and
show several concentric rings.

Stab Culture. This shows a slight granular growth along the line
of inoculation. Is most abundant on the surface, forming there a thin
grayish white covering. The gelatin is colored a yellowish brown.

Streak Culture. On agar, potato, etc., the growth is limited to the
line of inoculation. The growth is very good on fish, beef, bread, fats,
etc.

Oxygen Requirements. It is a facultative anaerobe. The produc-
tion of light depending upon the presence of oxygen, it is most marked on
the surface growths. The intensity of the light may diminish, or may
even become lost (attenuation), but may be restored by growth on suit-
able media, such as fish.

Temperature. Will not grow in the incubator. May grow at o C.

Behavior to Gelatin. Does not liquefy. It may ferment sugar.

Pathogenesis. It has no effect on animals. One species is said to
produce a disease in certain Crustacea.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 47

INFLUENCE OF ELECTRICITY ON BACTERIA.

Cohn experimented with electricity generated by two cells,
passing the current through a fermentable substance where bacteria
were present and found that they \vere not killed, but that changes
were produced which made the medium unfit for bacteriological
development. Later a stronger current of electricity was tried by
other investigators and some forms were killed, but the resistant
forms found in milk were not affected, which dashed the hopes of
those seeking a speedy method of sterilizing milk. D'Arsonval
and Charrin used a current of 10,000 volts on a certain species of
germ found in pus, but only a decrease in virulence was observed.

Electricity, however, is used in the manufacture of wine and
cognac for maturing the flavor and not for antiseptic purposes. A
certain mellow flavor is produced by pouring the liquors over plates
charged with electricity.

The results of these experiments proved that electricity was
not practical as a germicide, but that certain chemical reactions
were produced which were inimical to bacterial growth. If salt
were present in the current it would be either decomposed into acid
and alkali or set free, chlorine and hypochlorites. Sometimes per-
oxide of hydrogen and ozone w r ould be generated by the electric cur-
rent in sufficient amounts to destroy a number of non-resistent
forms. Heat also is generated which will destroy germs of the
same class.

It was expected that the X-rays would prove to be of value as
a germicide, but many experiments have resulted negatively. Like-

Plate 6. Bacillus Phosphorescens

Magnified 1,000 diameters.

48 CANNING AND PRESERVING OF FOOD PRODUCTS.

wise it has been demonstrated that Radium does not destroy bac-
teria to any appreciable extent.

INFLUENCE OF TEMPERATURE.

The subject of temperature is most interesting to canners and
manufacturers of food products because it opens up a way of suc-
cessfully destroying the scavengers which constantly menace those
products.

Bacteria grow best between the temperatures of 70 F. and
iooF., but are able to live through great changes which seem
marvelous to those who have not had experience and suffered losses
through their ravages.

There has been discovered one species of bacteria which multi-
plies at 32 F. It was discovered in 1887 by J. Forster growing on
the surface of salt water fish, a phosphorescent variety. Later it
was discovered by B. Fischer that the soil and also sea water con-
tained many varieties which could grow at 32F. A great num-
ber of these hardy varieties grow in milk and drain water.

Experimenters have tried various temperatures as low as 250
below zero, also in solidified oxygen for many hours, and some va-
rieties lived through the tests. Severe cold is germicidal to many
species.

This is interesting in connection with cold storage and ac-
counts for some peculiar changes we have witnessed. In a general
way it can be stated that the freezing point will retard decomposi-
tion of food stuffs, in fact 33 and 34 F. will keep fruits and vege-
tables very well for a long time, but there is loss in flavor from
the formation of CO 2 (carbonic acid gas), due to the breaking up
of small quantities of sugar, either by bacteria or the cell life of
the fruit itself.

The temperature required to protect meats and butter is con-
siderably lower than freezing, averaging about 13 to ioF., but
even in this temperature after a time certain changes may be noted
which are not due to bacterial action, (but are due to a loss of vola-
tile ethers which are retained by hard freezing.) Commerically, cold
storage is a good method of carrying over food stuffs of many
kinds, but of course decomposition will set in quickly after they are
brought into warm temperatures for the reason that their exposure
to germ-laden atmosphere has invited hosts of bacteria which will
start their functions when brought into warmer temperatures.

It is my belief that the cold storage system will come into
favor with the canner and preserver. In a series of experiments
recently tried, fruits and vegetables kept nicely when frozen solid.
Such products if subjected to I3F. freeze solid and retain their
flavor fairly well, but can only be used in jams and sauces, etc..

BACTERIA. DESCRIPTION AND CLASSIFICATION. 49

owing to the collapse which takes place when thawed out. Even
for these purposes, the system is advantageous, especially when
overcrowded with raw fruits and vegetables the canner can put
into cold storage his surplus, which may be made up later into
marketable products, when the receipts of raw materials are less.

The cost of building a cold storage plant for every canner is
too great to even be considered, but those whose factories are lo-
cated within a short distance of such a plant can take advantage
of it. Indeed a series of experiments along this line might prove
most satisfactory.

While we have found rare species of bacteria able to live and
multiply in freezing temperatures, it is interesting to note that there
are varieties able to thrive at an extreme temperature in the other
direction. These bacteria are non-pathogenic, that is, not disease
producing, in man and animal. They are. called thermophilous,
or heat loving bacteria, and one species was discovered by Miquel
called Bacillus Thermophilus, which multiplies at I58F. When
we remember that this temperature kills animal life and coagulates
egg albumen and blood serum, we are impressed with this remark-
able fact. This is an aerobic bacillus about i/* in thickness and
forms threads at about I4OF. and only thrives between the tem-
peratures of 98 and i62F. This bacillus is common in sewage
and is found in the alimentary canal of man and animals.

There are a number of bacteria which grow well at high tem-
peratures, most of which are found in the soil, in sewage water
and in the alimentary tract. During the extremely hot weather of
summer, these heat loving bacteria grow luxuriantly, and cause
fermentation where least suspected.

In this connection I wish to remind our readers that they may
have seen cans of improperly sterilized goods fermenting in the
center of a pile where the temperature would be almost scalding.
[ have seen cans of corn fermenting with so much heat that I could
scarcely hold a can in my hand. There has been very little investi-
gation into this phenomenon, but some of these bacteria will be de-
scribed and their resistance explained. There are certain kinds of
mold which have the same characteristics as the thermophilous
bacteria, and cause great loss, especially in the manufacture of cat-
sups and sauces made from tomatoes. Some of these molds are
pathogenic also, and are associated with disease in the lungs of
man and in the bronchial tubes and throats of birds.

Recently we examined the sputum of a pneumonia patient and
found the fungus growing; it is called Aspergitlus Fumigatus and
will be described later.

There have been discovered in the hot sulphur springs at
Ilidze in Bosnia, two kinds of bacteria, one called Bacterium Lud-
wigi, which developed at a temperature above I22F., and the

50 CANNING AND PRESERVING OF FOOD PRODUCTS.

Aspergillus Fumigatus, lachtheim

Origin. White bread, preserves, catsup, in the lungs and air pas-
sages of birds ; met with in man also.

Color. Greenish or bluish-green growth; resembles that of penicillium
very much.

Mycelium. Mycelial threads and spores are smaller than those of A.
niger.

Fruit-Organs. The fruit hyphae are club-shaped and covered with
sterigmae, from which extend rows of spores. The sterigmae are not
divided. The spores are usually colorless and from 2^/2 ^ to 3^ ^ in di-
ameter.

Growth. Rapid. Grows best on bread.

Bread Flasks. Low growth; at first bluish-green, but is grayish-green
when old.

Temperature. Grows best at 37-40 C. Will grow at ordinary
temperature, but not below 15 C.

Pathogenesis. Death was produced in a few days by intravenous
injections of millions of spores in rabbits and dogs. Mycelia were found
in the kidneys, heart and other muscles, and sometimes in the liver.

A pneumonic or pseudo-tuberculous disease is produced by the in-
halation of the spores in doves and other birds. Natural affections of this
kind are frequent among birds. They are met with occasionally in horses
and in cattle, and sometimes in man.

In mycoses of man, the lungs, eyes, ears or nose are subject to in-
vasion.

The Japanese utilize the growing A. Oryzae as a diastatic ferment.
Rice grains are converted by it into sugar and dextrin, which when sub-
jected to fermentation yields the national drink, Sake, containing about
14% of alcohol. Taka-diastase is a ferment which is derived from an as-
pergillus similar to that mentioned.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 51

other named Bacillus Capsulatus, produced endospores which lived
through a heat of 2i2F. for four hours without being destroyed.
We have called attention to the heat-resisting powers of spore-
bearing bacteria under the head of spores. Among these are sev-
eral varieties which are found on the skin of potatoes and in milk;
also one variety found associated with hay, malt, etc. These hardy
varieties found on potatoes are Mesentericus Vulgatus, Mesenter-
icus fuscus and Mesentericus ruber, the spores of the last able to
live through six to ten hours boiling at 2i2F. Bacillus subtilis,

Plate 7. Aspergillus Fumigatus

Photomicrograph of unstained mold Aspergillus Fumigatus, which sometimes makes its appearance on food
products, such as preserves, tomato sauces, etc. It is pathogenic. There are two fruit pods full of conidia near
the center. Just below the larger pod is one partially disgorged. Some of the loose spores or conidia may be
seen among the threads of the mycelium. Magnified 600 diameters.

a species found in boiled hay and malt infusions, gives rise to very
resistent spores and gave Prof. Tyndall so much trouble in his ef-
forts to overthrow the theory of spontaneous generation.

INFLUENCE OF LIGHT ON BACTERIA.

In a general way we may state that direct sunlight is detri-
mental to the growth of bacteria and is germicidal in many cases.
The effect of direct rays is injurious to cultures of certain species
which when thus exposed, lose their power to vegetate when re-
turned to the dark. The effect of sunlight may be noted in many
instances by its peculiar action on bacteria. Certain species which

52 CANNING AND PRESERVING OF POOD PRODUCTS.

are actively motile due to flagella (which will be described later),
lose their power to move and gradually weaken and die; others
which are called Chromogenic or color-bearing bacteria, (see sec-
tion on pigment producing bacteria), lose their function of pro-
ducing pigments; the pathogenic bacteria lose their power to pro-
duce toxins in some cases.

It is the ultra violet, violet, and blue rays of sunlight which
are so germicidal ; the green, red and yellow have very little or no
injurious effect upon bacteria. For extensive literature on this
phenomenon the reader is referred to Diendonne (A.G.A. iX, 405
and 537).

The diffused rays of sunlight have very slight disturbing in-
fluences on bacteria; likewise arc light and incandescent influences
may be observed.

The action of sunlight may produce chemical change in the
medium on which the bacteria are thriving, such as the oxidation
of fats, formic acid and formaldehyde and peroxide of hydrogen
may be formed, which will be germicidal. In this connection let
me say that these compounds are often formed in canned goods in
the steam retort by oxidation, and the analyses recently made by
certain state chemists were faulty in the extreme and produced the
impression that these chemicals had been purposely added to the
samples analyzed, when I know it to be a fact that they were not.
They should have known from the very nature of the goods they
were analyzing that oxidation would naturally take place at the
temperatures to which the goods had been submitted, that traces
of these germicides would be formed. Far be it from me to in
any way discourage the efforts put forth by conscientious investi-
gators to improve the quality of food, by condemning right meth-
ods ; but when the canning industry is assailed unjustly, and with
the motive possibly of gaining notoriety, it is proper to protect the
manufacturers and furnish them with information to refute false
analytical reports. I personally prepared two of the samples, ab-
solutely pure in every respect, which were submitted to the state
chemists and their report showed that formaldehyde and benzoates
were present, which was false in the sense that they had been add-
ed, and that report gave a wrong impression to the public. They
should have known that these had not been purposely added, but
that the faint traces were due entirely to oxidation produced by
steam heat 25oF., and that the product would naturally yield
traces of such preservatives.

To return to our subject, we have found that sunlight is
germicidal and that diffused light and electric light are slightly in-
jurious to bacteria. This will overthrow the idea that wrapping
with brown paper and storing in dark places fruits and vegetables
canned in tin and glass would prevent fermentation. Bacteria grow

BACTERIA. DESCRIPTION AND CLASSIFICATION.

best in the dark and the only value in the ancient custom, was pro-
tection from dust and protection of color, which sunlight injures
to some extent.

MOTIUTY.

My first impression when observing the rapid, almost marvel-
ous movement of certain bacteria was, that they must surely be-
long to the animalcules. So rapid was their movement that the
eye could not possibly follow them. Having focused the edge of a
hanging drop culture of the typhoid bacillus, I tried over and over
to move the slide and keep in focus with the fine adjustment of
the microscope, the swift moving germs, but they quickly passed
out of the field or dropped so deep in the fluid that it was impossi-
ble for me to follow them. Other active varieties also are apt to
create the impression that they are not a part of the vegetable
kingdom, but their life history and manner of vegetation dispels
the doubt.

Fig. 26

A Monotricha B Lophotricha.

a Cholera Bacilli. a Spirillum Undula.

b Sarcina Pulmonum. b Back Syncyaneum. b B. Prodigiosus.

c Typhoid Bacilli.

C Peritricha.
a B. Vulgatus.

Pasteur regarded the "vibrion butyrique" as an animalcule in
his early researches, but the higher order of algae have motile
spores and their movements are extremely rapid too, showing that
the vegetable kingdom does have actively motile species, and mo-
tility could not be an argument in opposition to their place in this
kingdom.

There are two kinds of motion observed in bacteria, one a
molecular motion, sometimes called "Brownian motion;" the other
is called independent motility. The former is purely a physical
motion and may be noticed in many particles held in liquid sus-
pension. There seems to be an oscillating motion peculiar to many
micrococci and bacilli, a rotary or orbit motion, due perhaps to the
vibration of the fluid. The molecules of the fluid may be round
like shot and roll over and over as slight chemical changes occur
or by shock or by the influence of the earth, etc. Certainly no one
has ever seen a molecule of water, but it seems probable that the
two atoms of hydrogen and the one atom of oxygen might combine
into a spherical molecule, and if such be the case there would prob-

54 CANNING AND PRESERVING OP FOOD PRODUCTS.

ably be great oscillation going on continually, thus accounting for
the peculiar movement described as "Brownian movement." Cohen
made some experiments which seem to lend color to the theory
given above. Gelatin was gradually added so that all the particles
held in suspension became quiet and he noticed that all bacteria
which had no independent motion, also became quiet, while the
bacteria which had an independent motion moved quite freely.

The subject has not been fully investigated and the theory
of molecular oscillation will probably stand.

Bacteria which have independent motion are endowed with
organs of locomotion which are most interesting to study. These
organs are called by different authors f la gel la, celia, or whips, which
grow out either from the ends or sides of the bacilli or both. The
number and kind of flagella often determine the species to which
a certain bacillus belongs. These organs of locomotion were first
discovered by Ehrenberg in 1836, and more carefully studied by
Cohen. It was supposed for a long time that only bacilli were
thus endowed, but in 1887 and 1890 Loeffler and several others
claimed to have discovered certain cocci which were motile, but
this is doubtful.

These fiagella are not visible when the bacteria are stained
with ordinary dyes; the most powerful objectives do not clearly
show their presence unless special staining is done to bring them
into view. Some bacteria have only one polar flagelltim. Others
have two or may have a bunch at the end; still others have them
evenly distributed over the entire surface of the cell, sometimes as
many as a hundred. The number and size of the flagella depend
upon the age of the cells. Usually they are best seen and studied
in cultures 24 to 36 hours old.

Flagella are very thin, hair-like appendages, so fine that the
dyes must be piled upon them to bring them into vision ; they vary
in length from two to twenty times the length of the bacillus and
seem to derive active power from the cell itself so that they im-
part peculiar motion to the rods ; some having a wabbling motion,
others a creeping motion, others a snake-like motion and still others
turn somersaults and whirl with a rapidity truly remarkable; and
the spirochetae have a boring or corkscrew movement. Bacilli are
classified with reference to the number of flagella (see Fig. 26)
into four groups monotricha , having one flagellum at the end ;
amphitricha, having a flagellum at both ends; lophotricha, having
a bunch of two or more at the end ; and peritricha, having the whole
surface arrayed with the hair-like whips.

These propelling organs are so delicate that they are easily in-
jured and fall off or become looped when disturbed by external
influences. When they are thus injured they disappear very soon
and are apparently dissolved in the fluid surrounding them. They

BACTERIA. DESCRIPTION AND CLASSIFICATION.

often fall off just at the time of spore formation. This is true of
nearly all species excepting some anaerobic bacteria. Old cultures
therefore are not suitable for the demonstration of flagella. I want
to emphasize this point because the beginner will have considerable
trouble, even under the most favorable circumstances, to stain the
delicate celia property ; a young culture is always to be preferred.

The influence of chemicals, antiseptics, salicylic acid, benzoates,
etc., is such as to cause loss of motion or death to bacteria, but
loss of motion does not always mean that the bacteria are dead.
Often they may be transplanted into favorable nutrient media and
become as actively motile as before. The enzymes and toxins which
are the products elaborated by the bacteria themselves when grow-
ing in a favorable substratum (nutrient substance), often cause loss
of motion and the agglutination (gathering, in bunches), tests are
made possible by this characteristic. This phenomenon is most
valuable to the bacteriologist in determining cases of typhoid fever.
Where the patient has typhoid fever the poison very early is dis-
tributed through the blood and this poisoned blood will cause the
agglutination of the typhoid bacilli when they are introduced into
a drop of the serum, diluted with bouillon.

Sometimes the microscopist meets with peculiar bodies in a
field or view where a pure culture of motile bacteria is being

Plate 8. Giant Whips of Malignant Oedema

Photomicrograph showing rods and giant whips. These large twisted bodies are visible in the water of
condensation without staining. Nearly all motile anaerobic bacteria produce these. Just what they are has not
been determined, but their presence is interesting. Magnified 2,000 diameters.

56 CANNING AND PRESERVING OF POOD PRODUCTS,

studied. Loeffler in 1890 observed large spindle-shaped bodies re-
sembling twisted hair. Later in 1893 Novy observed these same
bodies, which he calls "giant whips," while studying various an-
aerobic bacteria. Fischer, Sakharoff and Sames also describe these
large spindle-shaped bodies.

The spirals are very large, varying from 20 to ioo/u in length,
and may be observed without resorting to stains, in the water of
condensation of freshly inclined agar in tubes inoculated with cul-
tures of motile bacteria. They are motionless and have a wavy
appearance, or resemble a spindle wrapped in twine.

Plate 9. Giant Whips of Bacillus Butyricus Frumenti

Photomicrograph of Bacillus Butyricus Frumenti, showing ordinary flagella and also a bunch of giant
whips greasly resembling a bunch of hair. This is an obligative anaerobic bacillus found in corn and was ab-
tained from a swelled can of corn. The pressure of gas created by this organism is enormous, sufficient to burst
the cans. Stained by our special method from a young growth on 2 per cent, glucose agar. Photographed
through a 2 mm. oil immersion objective using acetylene radiant. Magnified 1,200 diameters.

The staining and demonstration of flagella will be fully ex-
plained later. It is accomplished only with great care and fine
mountings are obtained only by practice and patience.

CHROMOGENIC BACTERIA.

Chromogenic bacteria are the species which produce pigments
or colors of various shades and play an important part in the
deterioration of food products. There are two classes Chromo-
parous and Cromophorous.

CHROMOPAROUS, or color producing bacteria, are them-
selves colorless, but they produce pigments of various shades which
give distinct colors to the food stuffs on which they are growing.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 57

THE CHROMOPHOROUS group produce colors within the
cells, and may or may not give off the color to the media upon
which they are growing. The colors produced by the chromo-
genic bacteria can be distinguished by their behavior towards sol-
vents. The same bacteria always produce the same color when
grown in the same temperature and in the same media. Identical
colors may be produced by more than one variety, but the varieties
may be differentiated by the chemical reactions of their pigments.

The red colors are frequently seen like drops of blood on many
cooked vegetables, such as potatoes, starch, flour, egg albumen, car-
rots, meats, milk, onions and others which enter into the formulas
of soups, sauces, etc. Cane sugar syrup is often affected by these
colors. The oldest known bacterium producing a red color is Bac-
terium prodigiosum. Cultures of this organism were used by magi-
cians years ago to imitate blood spots on bread, whence its name
of "Bleeding bread" originated. There are several forms closely
allied to this, which produce various shades of red from a pink to
a deep brown red.

Milk is particularly subject to changes in color by these organ-
isms; also cheese; but such colors in these products may be pro-
duced by other causes such as blood, or madder (Rubia tinctorum
in the fodder fed to the cow. Sometimes cheese assumes a red color
from a purely chemical change caused by the oxidation of iron
compounds which develop during the ripening of the curd. These
chemical changes are quite easily distinguished from the red colors
produced by bacteria. More frequently cheese owes its red dis-
coloration to mold fungi belonging to the group of Eumycetes.

Dried codfish is very susceptible to red colors so that it resem-
bles salmon. Three different varieties which cause the trouble have
been studied by Le Dantec, who states that the loss is estimated
to be about ten million francs annually, since the people believe that
codfish affected with this color is poisonous.

YELLOW COLORS are produced by a number of bacteria,
but very few foods are affected by them excepting milk. Milk
sometimes develops a pale orange yellow and the bacteria causing
it were first studied by C. J. Fuchs in 1841 and by J. Schroeter in
1870, the latter isolating two microbes named Vibrio Xanthogenus
and Bacterium synxanthum as the' cause, but he claimed that they
were found in milk only after boiling. The yellow pigment pro-
duced by these germs is soluble in water, but not in alcohol nor
ether.

BLUE COLORS are produced by several varieties of mi-
crobes and the principal foodstuffs affected are milk and cheese.
Milk and cheese enter into the formulas for manufacturing so many
different varieties of food products that the manufacturer of soups

58 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Prodigiosus

MONAS PRODIGIOSA, OF EHRENBERG. MICROCOCCUS PRODIGIOSUS.

Origin. It is found on starchy substances, such as rice, potatoes,
moist bread; also on meat, albumen, milk, etc. Causes at times local
epidemics, infecting foods, as bread, sausages, meat, etc., to which it gives
a pinkish or red color. Bread so affected has been called "Bleeding
bread."

Form. A short rod, slightly longer than it is wide; it sometimes
forms threads, especially in slightly acid media or in old cultures; usually
single or in pairs.

Motility. It shows no motion ordinarily except a marked Brownian
movement. The slimy character of the growth decreases in acid or very
dilute media, and a slight motion may be observed. It has numerous long
wavy flagella.

Sporulation. This has not been observed. It shows marked resist-
ance to dessication.

Anilin Dyes. Stain readily.

Grozvth. The growth is very rapid.

Gelatin Plates. Deep colonies are round or oval, light brown in color
and with sharp border. The surface colonies are irregular, with rough
border, granular, have reddish center, and are surrounded by clear, lique-
fied gelatin.

Stab Culture. The liquefaction is rapid and funnel-shaped, and ex-
tends along the whole line of inoculation. A red scum is formed on the
surface of the liquid, which on settling colors the entire contents a bright
red.

Streak Culture. On agar, it forms a spreading growth which is moist
and abundant and of an intense red color, which is non-diffusible. On
potato, it grows very rapidly, producing slime and a pigment, which, when
old, has a metallic, fuchsine-like luster. Odor of trimethylamin. On
blood-serum, growth is same as on agar, with liquefaction.

Milk. Growth takes place and the fat globules hold the pigment in
solution. Coagulation results.

Oxygen Requirement. It is a facultative anaerobe.

Temperature. It grows best at ordinary room temperature. It ceases
to form pigment in the incubator and may lose this property temporarily,
i. e., become attenuated.

Behavior to Gelatin. Rapidly liquefies as the result of formation of
a soluble peptonizing ferment. In acid media this liquefying property
may be diminished or temporarily lost.

Aerogenesis. It has a strong odor of trimethylamin on potatoes, and
ferments sugar solutions.

Pigment Production. A bright red pigment is formed on various
media, and this is soluble in ether, alcohol, chloroform, etc. This pig-
ment is formed only in the presence of air and at ordinary temperatures
not at 37.

Pathogenesis. It is non-pathogenic. In large amounts its soluble pro-
ducts may have a toxic action. The cellular proteins may induce suppura-
tion. Animals which are not susceptible to malignant oedema may be ren-
dered susceptible by an injection of this bacillus. An injection of this
bacillus saves rabbits inoculated with anthrax.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 59

and sauces will no doubt be interested in these phenomena, which
he has perhaps frequently met with.

The principal microbe which produces blue colors in milk is
named Bacillus Cyanogenus; but blue discoloration may be ob-
served also in freshly drawn milk where the cow has fed on the
flowering rush (Butomus umbellattts) which contains a blue color-
ing matter frequently carried into the milk from the stomach of

Plate 10. Bacillus Prodigiosus, Flagellated
Magnified 1,200 diameters.

the cow through the arteries and mammillary glands. The dis-
tinction can easily be made between these two causes by adding a
small quantity of each kind of milk to normal milk. The one con-
taining the Bacillus Cyanogenus will soon produce the blue color
in the normal milk, while there will probably be no change notice-
able in the other.

Bacillus is a motile organism requiring oxygen for luxuriant
growth; the rods measuring from .3^ to .5^ broad to 1.4^ long.
When a dairy becomes affected with this organism it is most diffi-
cult to get rid of it, often requiring complete changes in all utensils
and thorough disinfection. This microbe grows well on vegetables
which have been cooked, such as rice and potatoes, which are used
in various formulas by the canner.

60 CANNING AND PRESERVING OF POOD PRODUCTS.

Bacillus Cyanogenus, Fuehs (1841)

BACILLUS OF BLUE MILK.

Origin. Found in blue milk.

Form. Small, rather narrow rods, having slightly rounded ends, two
to three times as long as wide. Frequently found in paris ; rarely in
threads.

Motility. It is very actively motile ; has bunch of whips at one end.

Sporulation. The small terminal bodies resembling spores are most
probably involution forms. True spores may form on althea or quince
jelly.

Anilin Dyes. Stain readily.

Growth. Rapid.

Gelatin Plates. The deep colonies are round, having sharp, smooth
border ; contents are yellowish and granular. The surface colonies are
round, moist, elevated, convex masses, finely granular and dark in color;
at times they may be thin and spreading, having an irregular border.

Stab Culture. In the lower part of the puncture there is little or no
growth. There is a thick, moist, dark-gray, spreading growth on the sur-
face. Gelatin is colored a dark steel-blue, the shade varying with the re-
action of the medium, being quite blue in neutral or acid media and dark,
or even black, in ver}^ alkaline media. It becomes dark colored when old.

Streak Culture. On agar, a dirty gray, thick, moist covering is
formed, the medium becoming dark colored. On potato, a similar growth
is formed which rapidly spreads and becomes colored. On blood-serum,
it forms no color.

Milk. It produces no acid or coagulation in sterilized milk, but the
milk is colored a slate-gray, which turns blue with acids. In unsterilized
milk, in the presence of lactic acid bacteria, the color is sky-blue. This
color develops from casein and not from lactose. In bouillon or milk con-
taining 2% of glucose, lactic acid and a fine blue color are formed. Lac-
tose is not converted into an acid.

Oxygen Reqnircnicn ts. Aerobic.

Temperature. Grows best at ordinary temperature, but will grow in
incubator. The pigment is most marked when it is grown at low tem-
peratures, 15 to 18 C.

Behavior to Gelatin. Does not liquefy. .

Patho genesis. No effect on animals.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 61

GREEN COLORING matter is excreted by quite a number
of bacteria, some of which in the presence of phosphates give the
green color while in other media their natural blue color is pre-
dominant; among these may be mentioned Bacillus pyocyaneus,
which causes the green color observed in meat which has been ex-
posed to the air. This is the same organism which gives rise
to the green pus often seen on wound bandages. Bacillus butyri
fluorsecens, a fission fungus, was discovered by Dr. T. Lafar in
1891 as the cause of green discoloration sometimes seen in but-
ter. Among the more common varieties which produce green pig-
ment, the following may be mentioned :

V r

% f

Plate 11. Bacillus Cyanogenus, Flagellated
Magnified 1,000 diameters.

Bacillus fluorescenes putidus, Bacillus fl. tenuis, Bacillus albus,
Bacillus viridans and Bacterium syncyaneum; while various molds
present a green appearance but do not impart their coloring to the
substratum upon which they grow. The mold Penicillium glaucum
gives the green color to Roquefort, Gorgonzola, Stilton and Brie
cheese. There have been discovered some twenty-seven species of
Penicillium. The green observed in several kinds of cheese it not
due to bacteria nor fungi, but to copper which was absorbed from

62 CANNING AND PRESERVING OF FOOD PRODUCTS.

Penicillium Glaucum

Origin. It is widely distributed in air, water and soil. It is said
that sixty per cent of the mold contaminations in the laboratory are due
to it.

Color. Whitish at first, changing to a bluish-green later.

Mycelium. Is composed of straight or slightly wavy mycelial threads
horizontally arranged; from these the fruit hyphae rise vertically.

Fruit-organs The ends of the septate fruit hyphae are forked; they
are covered with sterigmae, sometimes called besidia. Each of these
sterigmae bears a row of eight spores or conidia, giving to the whole the
appearance of a brush. The spores are about 3.5 //, in width.

Growth. Rapid.

Gelatin Plates. Whitish floccules are formed by the colonies; these
gradually increase in size; at the same time the center becomes a green
color. The gelatin is liquefied early. The above characteristics may be
seen by means of a low objective.

Bread Flasks. A low, finely flocculent covering is formed, white at
first, but changing to green later.

Temperature. Optimum, from 22 to 26 C. will not grow at body
temperature.

Behavior to Gelatin. Liquefies slowly.

Pathogenesis. No effect on animals. It often develops on grapes and
causes a marked alteration in wine. Gives rise to diastatic and inverting
ferments. It is said to be used in the preparation of Roquefort cheese.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 6S

Plate 12. Penicillium Glaucum

Magnified 600 diameters.

Plate 13. Penicillium Glaucum

Photomicrograph of a bluish green mold belonging to a species of Penicillium, which was found on the-
surface of jelly. The photograph was made of the living plant and shows the mycelium, hyphae and spores.
The spores are flat on both sides and are capable of setting up fermentation when submerged in fruit juices. It:
will form alcohol, some acid and phenol-like bodies. Magnified 500 diameters.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 65

copper utensils, in which the milk had been kept. The lactic acid
formed, attacked the copper, which turned green in the yellow
cheese.

Canners of meats should guard against the use of meat which
shows any green discoloration. The presence of the green pigment
indicates that the meat has been exposed to warm temperature and
may have more deadly parasites flourishing on the surface and in
the tissues than the color-bearing germs. There are various bac-
teria and fungi which produce other colors such as black smut and
white spots. Packers of corn often experience trouble with black

Plate 14. Yellow Mold

Photomicrograph of a beautiful yellow colored mold isolated from the surface of California tumbler jelly.
This is a very rare species and grows in almost similar manner as Penicillium, having the branched hyphae and
the long rows of conidia or spores at the end. This specimen was photographed from the edge of an agar
growth in the living state, sunlight being used in two ways, both direct and by transmission, giving the plate a
beautiful relief-like effect. Magnified 500 diameters.

spots throughout their cans, sometimes due to these, which will be
fully described under the head of Corn Packing. The packers of
canned lobsters have had considerable trouble at times with black
discoloration, as also do packers of various sea foods, all of which
will be described in their proper places.

There are varieties of bacteria which produce violet and pur-
ple colors which are useful in the manufacture of indigo and other
shades, but have no importance in the manufacture of food prod-
ucts.

CANNING AND PRESERVING OF FOOD PRODUCTS.

BACTERIA PRODUCING SUMS AND ROPINESS IN FOOD PRODUCTS.

Viscous fermentation is a most important study for the can-
ners of molasses, syrups and vegetables, such as peas, string beans,
asparagus, etc. Grape sugar is often split up by Invertin, pro-
duced by several varieties of bacteria which form mucinous cap-
sules and grow in zoogloea or masses all united. There are cocci
which grow on some foodstuffs without forming the gelatinous
capsules. The capsules are formed as a sticky envelope around
the cocci, and sugar, lactose, maltose and dextrin seem 'to favor
their development. The capsules are stained by special dyes and
are not revealed by ordinary staining.

Fig. 27. Leuconostoc Mesenteroides

a. b. Chains of non-capsuled variety. c. e. Cells with gelatinous capsules in
various stages of development. (X 1,200. After Ljesenburg and Zopf.)

The principal cause of this viscous fermentation in cane sugar
are the Leuconostoc mesenteroides, which were studied by Van
Teighem in 1878, who published his researches, but he probably
had several varieties mixed, as his drawings show chains of cocci
and diplococci. In 1891, however, C. Liesenberg and W. Zopf ob-
tained pure cultures of the organism and found it to be a coccus
o.S^i to 1.0^ in diameter.

This germ does not develop the mucinous matter when grow-
ing on nutrient substances free from sugar, but when grown on

BACTERIA, DESCRIPTION AND CLASSIFICATION. 67

vegetables like peas, beans, beets and carrots, which contain saccha-
rose and dextrose, zooglea forms appear, somewhat dry at first,
afterwards becoming softer and sticky. Frequently whole vats of
molasses will be contaminated by this microbe and when it acts on
cane sugar syrup, it produces the invertin which retards crystalli-
zation. The capsule which surround it protects it and enables it
to withstand high temperatures.

Another cause of viscous fermentation is the Bacillus Vis-
cosus Sacchari, which differs from the last organism described in
that it converts the media on which it develops into a viscid mass
and does not form the envelope around the cell.

There are several other varieties which cause viscous fermen-
tation, viz. : Bacillus megatherium, Bacillus fluorescens liquefaciens,
Bacillus vulgatus and others which produce changes in saccharine
products, giving rise to mucus, amyl alcohol and invertin. Milk
frequently becomes ropy or slimy so that it can be lifted up in long
stringy threads, sometimes a yard in length. Alcohol and acetic
acid are often generated in this kind of milk by two organisms
isolated by E. Duclax, called by the generic name Actinobacter
or lustrous bacteria.

Bacillus mesentericus vulgatus (Flugge) and Bacillus pitui-
tosi (Loeffler) are most frequently the cause of ropiness, but re-
cently I have observed a short, plump capsuled bacillus in cream
which had become ropy. This bacillus when grown on nutrient
agar develops the capsules and takes the stains quite readily. It
resembles the Bacillus lactis viscosus, discovered by L. Adametz
in 1890. All these organisms develop at times in milk which is
allowed to stand in a warm temperature ; this is easily avoided, but
there is another organism which develops ropiness at a lower tem-
perature. It is a large micrococcus about 21*. in diameter, easily
killed by boiling temperature.

The peculiar flavor of Edam cheese is clue to a fission fungus
called Streptococcus hollandicus, cultivated in pure cultures by the
Dutch dairymen and cheesemakers. Milk, when sown with this
fungus, soon becomes ropy and the ropy whey is made into the
famous cheese.

In Finland, Sweden and Norway the milk pails are rubbed
on the inside with the leaves of the butterwort (Pinguicula vul-
garis) and the cows are fed with the plant. The leaves of this
plant are infested with the micro organism used by the Dutch
cheesemakers, consequently the milk is soon ropy, and this thick
milk, is a commercial article among the Scandinavians.

Soapy or frothy milk with a slimy sediment is due to a mi-
crobe called by Weigmann, Bacillus lactis saponacei, usually the
result of unclean bedding for cows. Many of the impurites in milk
are due to the uncleanly methods of dairymen, and it is hoped

68 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Mesentericus Vulgatus, Flugfge

POTATO BACILLUS.

Origin. They are widely distributed in the soil, on the surface of
potatoes, in faeces, putrid fluids, milk, water, etc.

Form. Small, thick rods, having rounded ends. Usually found in
pairs ; may form threads.

Motility. It is actively motile, having numerous flagella.

Sponilation. Large, medium, roundish spores are readily formed.
Globing describes one variety which showed enormous powers of resist-
ance, withstanding the action of steam heat for five to six hours.

Anilin Dyes. React easily, as does also Gram's method.

Growth. Very rapid, resembling in many respects that of the hay
bacillus.

Gelatin Plates. The colonies are yellowish-white, slightly granular,
with irregular borders, liquefying rapidly and extensively.

Stab Culture. Growth along er.tire line of inoculation, liquefaction
being more energetic in- the upper part. The liquefied gelatin remains
turbid for some time. A thin, grayish, folded scum is formed on the
top.

Streak Culture. On agar a dull white or grayish growth is formed.
The most characteristic, growth develops on potato. The surface is rapidly
covered with a thick, white, strongly folded, coherent growth, which
later becomes a dirty brown or red color.

Mild. Casein is coagulated and peptonized, and starch is inverted.

Oxygen Requirements. Aerobic.

Temperature. Growth at ordinary or at higher temperatures.

Behavior to Gelatin. Liquefies rapidly.

Pathogcnesis. No effect has been observed.

Th.ere are several varieties of potato bacilli, some forming a red and
others a brown growth on potato. The spores of the potato and hay ba-
cilli are extremely resistant it may require an exposure of ten hours or
more to steam to insure sterilization when the material is in a small mass,
not in a fine state of suspension.

BACTERIA. DESCRIPTION AND CLASSIFICATION. 69

that more stringent laws may be passed to keep this universal
food product purer and more wholesome. Milk is so extensively
used in the manufacture of delicate soups, sauces and table delica-
cies that its special study is desirable.

V
v

' -

Plate 15. Bacillus Mesentericus Vulgatus, Flagellated
Magnified 1,200 diameters.

In the manufacture of Worcestershire sauce, wine is used fre-
quently, and is sometimes found to be ropy and slimy, the flavor
greatly injured. The study of this subject is one more for the.
wine maker than the manufacturer of food products, yet it is well
to know that such wine is not fit for use and the trouble is due
to fission fungi studied by Pasteur, arid are Bacillus viscosus vini
and other similar species.

The same scientist investigated the cause of beer and wort be-
coming ropy and found a fission fungus which he named Micrococ-
cus viscosus. This organism does not give rise to violent fermen-
tation, but seems to perform its functions in the development of a

70 CANNING AND PRESERVING OF FOOD PRODUCTS.

gelatinous viscid envelope which spreads through the whole liquid.
H. Van Lear obtained pure cultures of two varieties, naming them
Bacillus Viscosus I and II, differing in the quantity of carbon
dioxid liberated and the amount of viscous matter; the first pro-
duces yellow patches and the second a brown formation.

These two organisms, contrary to the general character of
viscous ferments, do not require sugar in very large quantities to
produce the gelatinous envelope, in fact sugar is injurious to them.
In the manufacture of malt and cider vinegar these organisms make
their appearance, frequently causing a great deal of trouble. The
alcohol is favorable to their development but the acidity is germi-
cidal. About 2 per cent, acid stops development.

Plate 16. Bacillus Vulgatus Viscosus, Flagellated

Photomicrograph of a slime-forming, actively motile bacillus. This is a spore-bearing organism similar in
some respects to Bacillus Vulgatus in its formation of slime. Incompletely sterilized molasses is fermented and
rendered very viscous by the decomposition of sugar. The flagella are stained by precipitating the slime with
chloroform and staining as usual, although many difficulties beset the microscopist. Magnified 1,000 diameteas.

Viscous fermentation is not confined to the family of bacteria
(Schizomycetes) alone, but may be caused by some of the Eumy-
cetes or yeast and mold fungi as well.

The canner and preserver has difficulties of this nature, par-
ticularly canners of molasses, syrups, peas, beans, corn, asparagus,
etc. Owing to the heat resisting power of many species which are
protected by their gelatinous capsules, sterilization is sometimes
difficult. To be sure the temperature may be increased and the

BACTERIA. DESCRIPTION AND CLASSIFICATION. 71

time lengthened, but the quality is thereby injured. It would be
no trouble to increase the process of peas to one hour at 25oF.,
which would perfectly sterilize them, but the result would be more
of a soup than canned peas they would all cook to pieces. The
remedy lies in another direction; the raw product must be properly
cared for, and not allowed to stand exposed to these scavengers.
There has been considerable carelessness in this matter in the past.
Raw material often stood exposed until the slimy formation could
be detected by the hand. I remember when the new pea vining ma-
chinery first came into use, the hulled peas were hauled several
miles on wagons in baskets eight inches deep. They were unloaded
and piled up for several hours before they were canned, and the
baskets were very slimy and the peas stuck together so that the
grading machines were scarcely able to properly sort them into
various sizes. The cans opened after the season were ropy and
the peas were flat and had lost their delicate flavor.

The canners of molasses who do not take proper care of the
unrefined molasses will experience great difficulty in preventing
fermentation. They have been resorting to preservatives as a
means of preventing fermentation and overcoming the difficulties
with which they are beset through careless methods.

72 CANNING AND PRESERVING OF FOOD PRODUCTS.

CHAPTER III.

Principles of Bacteriological Technique

Methods of Cultivating Bacteria. Artificial Media. Method
of Cultivating Anaerobes. Methods of Simple Staining.
Method of Staining Flagella. Method of Making Photomi-
crographs.

When foodstuff is attacked by bacteria there may be and gen-
erally are, several varieties involved, and it is essential that these
varieties be separated and studied in pure cultures under all con-
ditions. If the canner is having losses from swells and sour goods,
he is anxious to know what is the cause; the preserver has mold
appear on the surface of his jellies and preserves, and he is mysti-
fied as to the cause; the packers of corn and such special foods as
lobster, and fishballs, find the contents spotted black and the juices
are turned dark, and the mystery deepens; the packers of meats
and fancy soups sometimes receive notice of ptomaine poisoning,
where certain cans of their goods are held responsible, and they
are totally in the dark as to the cause; bottlers of tomato catsup
suddenly lose a large per cent, of their goods, where every detail
of the work seems to have been carried on as in former years ;
picklers are surprised to find soft pickles, where their old and tried
methods of salting have been followed closely. In fact there is
hardly a single line of goods but that shows signs of spoilage at
certain times under the most peculiar circumstances. Xow when
this spoilage occurs there is something to blame, and if you have
carefully watched your pack, you will have received warning of
brewing trouble. A can will swell and you pick it up, turn it over
and look for a possible leak ; the capping and tipping are smooth ;
the top and bottom appear all right, but the seam looks as though
there might be a leak, and you pass over the matter; this may be
a warning that the process is wrong, and if you let the matter drop
you may find out suddenly that a large per cent, of your goods are
going wrong. When a can shows signs of swelling a thorough
bacteriological examination ought to be made at once. If the can
is only a leak, there will be found growing inside various germs,
which would have been destroyed in a single boiling process, and
this would be fairly conclusive evidence that there was a leak
somewhere in the can, possibly so small as to escape the most rigid
scrutiny. If the can is a sw r ell caused by an underprocess, the
plate culture method will show r only spore-bearing species of bac-

PRINCIPLES OF BACTERIOLOGICAL TECHNIQUE, 73

teria, and if this be the case, the process must be examined care-
fully; first, to see if everything is in good working order; second,
a careful test of thermometers and gauges ; and third, to see if the
processor is giving the goods the required time and temperature.
If all these are found to be correct, then cans must be inoculated
with pure cultures of the bacteria and then incubated at 98 F. If
they swell they show insufficient sterilization. Sometimes the cans
do not swell, but still contain germs, which will decompose the
sugar into acid, which phenomenon is known among canners as
"sour goods," so it is well to cut open a few cans and streak some
Petri dishes containing nutrient agar and gelatin, and put part of
these in the anaerobic culture apparatus, and others are to be grown
in the incubator, covered, but allowing circulation of atmosphere.
Hanging drops of the liquid in the cans should be made and care-
fully watched under a 1-12 oil immersion lens. If living bacteria
are numerous, they may be seen to move rapidly through the
fluid.

Nearly all the spore bearing bacteria are motile, possessing,!
usually, numerous flagella, which we have reproduced in various
photomicrographs throughout this work. As we have previously
stated, the flagella are not visible when examining living bacteria;
they are seen only after staining according to special methods
which we will describe later in this chapter.

The preparation of nutrient media for cultivating bacteria is
essential for bacteriological research and for general purposes the
following formulae are used, but for special study the best nutrient
materials are made with the fluids of such goods as are spoiling;
for instance, the bacteria found in spoiled peas should be grown
upon the sterilized juice of peas, or if it be spoiled corn, the medium
should contain as a base the filtered sweet corn juice, etc.

ORDINARY MEDIA.

BOUILLON. This is made from fresh lean meat juice and is
used generally to demonstrate certain peculiarities of various species,
to differentiate species, and aid in their identification. Sometimes
the bouillon is densely clouded, sometimes only slightly; a thick
sediment may form, and this precipitate may be easily diffused by
shaking, or may be too heavy ; some cultures form pellicles or skins
over the surface, and these may be easily broken (by shaking the
tube) or may be very tenacious. The indol reaction with sulphuric
acid is best demonstrated in a bouillon culture. Bouillon is an ex-
cellent medium for growing the various germs which produce pto-
maines and toxins; the germs may be filtered out by forcing the
liquid through a porcelain, or Chamberland filter, and the analysis
may be made of the filtrate for such poisons. Bouillon cultures

74 CANNING AND PRESERVING OF FOOD PRODUCTS.

are made of the various germs which are used in agglutination
tests, described under Typhoid, in Chapter V.

FORMULA. 500 grammes (about 17 ounces) of lean beef
are cut up into small pieces ; there must be no free fat ; the meat is
covered with 1,000 cubic centimeters, or one litre (about one
quart), of distilled water, and let stand in refrigerator 24 hours.
Squeeze out all the juice possible from the meat and strain through
flannel, or, better still, gently simmer over flame for one hour, and
then strain. The flame should not come directly in contact with
the bottom of the enameled pan, so a sheet of asbestos is placed
between the flame and the pan or one with a double bottom may
be used. If, after this, the volume is short of 1,000 c.c., add
enough distilled water to make up the amount, then add 10 gram-
mes of Merck's meat peptone, and 5 grammes of common salt. Put
the mixture into the autoclav or process retort and raise the tem-
perature very slowly up to 24OF. and hold for 30 minutes; after
removing, strain through four thicknesses of flannel and let stand
until cold, then filter through ordinary filtering paper. Test the
bouillon with blue litmus paper and it changes the color to red,
which shows an acid reaction. As most bacteria grow better on
slightly alkaline media, prepare a strong solution of carbonate of
soda and stir into the bouillon, just enough to turn red -litmus pa-
per slightly blue. Care must be taken not to add too much alkali,
for in the preparation of agar it is almost impossible to obtain a
clear filtrate.

The bouillon is now a beautiful golden color and clear. A
number of tubes can be filled about one-fourth full and the balance
filled into Florentine flasks for future use. The necks must be
stuffed with tightly twisted absorbent cotton, and all the tubes and
flasks then put into the autoclav and sterilized for thirty minutes
at 24OF. ; then after removing they must be kept in a dark place
so that no sunlight shall strike them. As mentioned in last chap-
ter, strong sunlight will cause the formation of dioxygen, formalde-
hyde and traces of other antiseptics, through the oxidation of
sugars and fats.

Dextrose and Milk Sugar Bouillon may be made by adding 2
per cent, of either to the bouillon. This combination is used to
demonstrate biological peculiarities of various bacteria towards
sugar. In the same manner and for the same purpose, Glycerin
Bouillon is made by adding 4 per cent, glycerin to ordinary bouil-
lon. Carbolic acid is added to bouillon ; 6 per cent, of a 5 per cent,
solution of carbolic acid will retard the growth of undesired bac-
teria, and is used in the isolation of certain germs found grow-
ing with very many different species, which under ordinary cir-
cumstances grow too luxuriantly, and crowd out the species sought.

PRINCIPLES OF BACTERIOLOGICAL TECHNIQUE. 75

SOLID NUTRIENT MEDIA.

To Dr. Koch of Berlin belongs the credit of this valuable
discovery : that nutrient bases could be solidified in gelatin and
agar-agar, and that bacteria, when mixed throughout the mass,
would grow and form colonies of their own kind, and would not
extend very far (if sufficiently separated) to become mixed. By
means of this class of media nearly all pure cultures are obtained.
If Pasteur had taken advantage of this valuable method in his time,
a great part of his labors would have been made easy, and the
science of bacteriology would have made greater progress than it
has, although wonderful discoveries have been made, yet the possi-
bilities are almost unlimited. Outside of electricity, we believe that
there is no science which has the possibilities that lie within the
range of the bacteriolgist. There are a number of diseases, the
cause of which is still mysterious, there being no definite organism
known to be responsible; there are smallpox, scarlatina, yellow
fever, foot and mouth diseases, rhinderpest, syphilis, and many
other diseases which have not been traced positively to specific
micro-organisms, and there are a number of cases of spoilage in
foodstuffs which have never been investigated, so that we cannot
help regretting that Pasteur did not give us at least twenty years
advancement by using solid nutrient media in his time. We owe
to this great genius much of our present knowledge, but how much-
more he might have discovered with solid nutrient media to facili-
tate his labor is only a matter of speculation.

GELATIN MEDIA. Make the same quantity of bouillon as
previously given, leaving out the peptone and salt; pour over this
100 grammes of fine gelatin, 10 grammes of peptone, and 5 gram-
mes of common salt. Dissolve these by placing pan in boiling
water, and after they are thoroughly mixed make slightly alkaline,
as directed under "bouillon." Place the solution in the filtering
apparatus (Novy's), attach suction pump and filter, or filter through
four thicknesses of flannel if you have no other means. The liquid
is then poured into tubes and Florentine flasks stoppered with cot-
ton and sterilized at 2i2F. for one hour on three successive days.
If it is desired, Petri dishes may be placed in the autoclav and
sterilized at the same time, and these may be filled with the gelatin
medium. When sterilizing Petri dishes I have found it wise to
turn both tops and bottoms upside down in wire basket, which
prevents the accumulation of condensed water, so undesirable. The
gelatin will harden if placed in a temperature below 75 F., so the
best method is to place it in a refrigerator. Since gelatin melts at
about 75 F., it cannot be used advantageously in hot weather, but
in cold weather is advantageous, because it is very clear, is easily
prepared, and the colonies of bacteria grown on it have more char-
acteristic peculiarities than on agar.

76 CANNING AND PRESERVING OF FOOD PRODUCTS.

Special preparations may be made with gelatin by adding
grape sugar, milk sugar, glycerin or carbolic acid, as directed un-
der ''bouillon."

Solid culture media can be made by using gelatin with the
juices of fruits, vegetables and the liquid or special food prepara-
tions. Usually 10 per cent, gelatin will be found sufficient.

These special gelatin preparations have great value in the
study of food spoilage, because the organisms in pure cultures will
produce the very changes so often observed in spoiled canned goods,
while in the regular meat juice gelatin these special characteristics
may not be revealed.

For the cultivation of the heat loving bacteria, the lactic group,
and many pathogenic species, gelatin is not very satisfactory, since
it cannot be incubated, but for the demonstration of liquefying bac-
teria it is fine, and furnishes means of differentiating species, where
agar and even blood serum fail to reveal this characteristic.

AGAR -AGAR MKDFA.

AGAR- AGAR is prepared from a sea\veed which grows on
the coast of China and Japan, and is used in the place of gelatin,
over which it has many advantages. It is more difficult to prepare,
however, and considerable time and care must be given it to pro-
duce a good clear medium. Formula : The meat juice is prepared
as directed under the head of "Bouillon/' and 10 grammes of pep-
tone and 5 grammes of salt are added, as directed under "Gelatin,"
but instead of gelatin I to 2 per cent, agar is used. The agar is cut
up quite fine, and thoroughly washed after being weighed. Place
the pan in the autoclav and slowly raise the temperature to 240 F.,
maintaining same for about 10 minutes; then lower the pressure
and filter the fluid through Novy's agar apparatus, having previous-
ly made the liquor slightly alkaline with sodium carbonate solution,
using great care not to add too much to avoid cloudiness. Novy's
apparatus gives a clear, golden filtrate, which is beautifully trans-
parent after solidification. Flasks and tubes are filled as directed
under "Gelatin," and these, with the desired number of Petri dishes,
are placed in the autoclav and sterilized at 240 F. for 35 minutes.
The agar does not solidify until the temperature falls to IO2F.,
and the tubes may be slanted by laying them down so that the liquid
agar will flow up towards the cotton pretty well ; by raising the
mouth of the tube, any desired slant may be obtained. The Petri
dishes are filled while the agar is still hot. There is always con-
siderable condensation water left on the surface of solidified agar,
and to minimize this the temperature of the dishes should be about
the same as that of the agar when it is poured out. After agar
has solidified it does not melt again except at high temperature.

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE. 77

thus it has the advantage over gelatin, in that it may be kept at
blood temperature in the incubator. There are a number of bac-
teria which require this temperature for characteristic growth. Agar
is the best medium for growing motile bacteria which are to be
stained to demonstrate their flagella. Bacteria, when grown on
gelatin or in fluids, carry with them so much of the medium upon
which they are growing that the flagella cannot be stained properly.

Various combinations of agar are made for special cultures,
such as those described under "Gelatin." Chemicals, such as sac-
charate of iron or tartrate of iron, may be added to agar to demon-
strate the production of sulphuretted hydrogen by certain species
of bacteria; lactose and sterilized litmus tincture are sometimes
added to demonstrate the ability of certain species to cause fer-
mentation of lactose and the production of acids. Agar may be
streaked with sterilized blood to cultivate special bacteria. In fact
agar is the best nutrient medium for general purposes.

POTATO MEDIA. The growth of many species of bacteria
on potato is often of great value in assisting the bacteriologist to
identify them. Owing to the very resistant forms of germ life
found naturally on potatoes, it is difficult to prepare sterile media.
There are three varieties of bacteria found growing on the surface
which will withstand considerable boiling to destroy the spores ;
they are Mesenterictis vulgatus, Mesentericus fuscus and Mesenter-
icus ruber, the spores of the latter being able to withstand six to
ten hours' boiling. To prepare potatoes, they must be thoroughly
washed in water and the eyes removed, then sterilized in the auto-
el a v for fifteen minutes at 240 F. Before they are removed, the
hands should be washed in a bi-chlorid of mercury solution, I to
1,000, and a sterilized knife may be used to cut the potatoes in
halves lengthwise. Place the pieces, cut side up, in culture dishes
having filter paper in the bottoms. The filter paper should be wet
with the mercury solution, to prevent contamination. The surface
of the potato may then be streaked with the pure culture of the
bacteria. This work may be simplified by cutting the potatoes into
slices and sterilizing in autoclav for twenty minutes at 25oF., and
then transferring into sterile Petri dishes.

Potato juice may be combined with agar i V 2 per cent., or
gelatin 10 per cent., and a small quantity of I per cent, solution
iodide of potassium, and sterilized thirty minutes at 240 F. This
is an excellent medium for growing the typhoid bacilli, because it
is slightly acid, and the bacilli form threads which have a beautiful
serpentine movement.

MILK MEDIA. Milk is used to demonstrate the power of
coagulation of certain bacteria, also to show whether they produce
acids or alkalis, or whether their action is amphoteric. Milk is
difficult to sterilize, owing to the presence of spore-bearing bacteria,

78 CANNING AND PRESERVING OP FOOD PRODUCTS.

which are very resistant to heat. Too much heat changes the
chemical composition of milk, so that when boiled at 2I2F., citrate
of lime is deposited or precipitated, and there are formed such
antiseptics as formaldehyde and peroxid of hydrogen. The milk
fresh from the cow, taken under aseptic precautions, is best, be-
cause it may thus be obtained almost free from bacteria. Fill the
milk into sterile tubes, plug them with cotton, and heat to i6oF.
for one hour for five successive days, keeping same always in a
temperature not to exceed 70 F.

Tincture of litmus added to milk until slightly blue, before ster-
ilizing, is very useful in determining the acid, producing power of
certain species of bacteria. The formation of acid will change
the color to pink or red.

For most purposes, milk put into test tubes and sterilized for
fifty minutes at 25OF., will prove satisfactory; the chemical alter-
ations are not so great as to interfere with the study of non-patho-
genic bacteria. Milk is not a good medium for growing bacteria,
except for the purpose indicated, because it is not transparent and
if solidified by adding gelatin or agar and used for plate cultures,
the colonies of bacteria are very hard to find. The milk may be
coagulated, however, and the clear fluid used with peptone and
salt and solidified with 10 per cent, gelatin, or 2 per cent, agar, and
have value in the cultivation of bacteria associated with milk.

BLOOD SERUM. This nutrient medium is valuable for
growing various germs which produce ptomaines and toxins. The
power of liquefying solidified serum is useful for identification of
species. The blood is taken from the animal under aseptic precau-
tions and allowed to stand one day in refrigerator, when the serum
may be drawn off and filled into tubes. The serum will be sterile
if due care has been exercised. Tubes of serum may be sterilized
in Koch's blood serum sterilizer one hour at I5OF. for five suc-
cessive days. They may be solidified in Koch's apparatus for soli-
difying blood serum by heating to I7OF.

' BREAD MEDIA FOR CULTIVATING MOLDS. Bread,
when made moist, is acid in reaction, and is a nutrient medium for
molds ; bacteria do not grow well on acid media, so the isolation of
various species of Hyphomycetes is made easier, because acid is
favorable for their growth. Fine bread crumbs are collected in
the bottoms of several test tubes and sterilized water is added, suffi-
cient to make a paste. The tubes are sterilized by boiling for three
successive days at 2i2F. for fifteen minutes.

METHOD OF MAKING CULTURES.

In order to determine the different species of bacteria which
are causing spoilage or disease, it is necessary to separate them one
from another and study them in pure cultures. It rarely happens

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE. 79

that one species is found alone; there are usually various kinds of
bacteria growing together, and to separate them requires careful
manipulation, which is easily accomplished by practice, and aseptic
precautions. If we desire to cultivate the various bacteria found in
a can of sour goods, w r e proceed as follows : A bunsen flame is
forced clown on to the surface of the tin, and a sterilized awl is put
into the flame and pushed through the tin; if any air is sucked into
the can by a vacuum, it is sterilized in the rlame which covers the
hole; a long platinum looped wire is then heated to incandescence
and put down into the can through the hole and quickly with-
drawn, and the loopful of material is transferred to liquefied gelatin
and agar tubes and dishes, previously prepared as follows : The
gelatin, tubes are liquefied in warm water, and after singeing the
cotton plug in the flame, tube No. i is inoculated by holding tube
in slanting position in left hand, removing cotton plug with little
finger of right hand, and then rubbing up the loopful of material
on one side of the tube, mixing it with the gelatin ; the plug is then
put in and the gelatin mixed thoroughly by rolling and gentle shak-
ing. The platinum loop is then sterilized in flame and tube No. 2
is inoculated from No. I, both being held in a slanting position in
left hand and the plugs of each removed in succession with little
finger of right hand. Two or three loopfuls of gelatin from Xo. i
are transferred to No. 2, and the plugs replaced ; the gelatin in No.
2 is then shaken, the platinum loop sterilized as before, and in the
same manner tube No. 3 is inoculated with two or three loopfuls
from No. 2. After shaking and mixing thoroughly, all three are
poured into sterilized Petri dishes and placed in refrigerator or on
ice to solidify the gelatin, after which they are maintained at about
70 F.

In like manner a number of tubes are inoculated and placed
in the anaerobic culture apparatus after chilling. It usually hap-
pens that No. i and No. 2 have too many colonies, which cannot
successfully be separated before they grow 7 together, but No. 3 usu-
ally contains but few colonies, which may be studied carefully as to
color, shape, size and border, also the liquefaction of gelatin, if any
occurs. Observations must be made and noted of their appearance
in natural size, then of their appearance under various magnifica-
tions.

Agar plate or Petri dish cultures are made in the same man-
ner, except that the agar is melted first in autoclav at 240 F., and
then poured into tubes. The agar solidifies at IO2 C F., so this must
be borne in mind and the work must be done quickly, at about

I20F.

Gelatin is difficult to manipulate in hot weather, and cannot
be incubated, so it is advisable to make cultures on agar as well
as gelatin. The writer has been successful in isolating the various.

80 CANNING AND PRESERVING OF FOOD PRODUCTS.

species in Petri dishes alone, without using the tubes, as follows :
The agar is liquefied and poured into the sterilized dishes, and just
before it begins to harden transfers are made by mixing a loopful
of the suspected material in dish No. i, using a long platinum loop-
ed wire and holding the lid of the dish up from the edge just high
enough to permit thorough mixing. By a gentle swaying motion
the mixing can be made uniform. Transfers are then made to a
second and a third dish, as described in method of inoculating
tubes, the platinum loop being sterilized between each transfer. Dish
No. i will usually have too many colonies, which will grow to-
gether before they are old enough to show special characteristics;
No. 2 may be better, but No. 3 will probably contain but few
colonies, which may be carefully studied .and transfers made to new
dishes, which are streaked by pushing a sterilized platinum loop
into a colony (or if the colony is very small, a needle is better),
and the surface of the new dish is streaked by simply drawing the
wire over the surface. Some care is required in handling Petri
dishes; if. there be any water of condensation either on the surface
of the agar or on the under side of the cover, it should be set to
one side and not used until this evaporates. Freshly made agar
usually has considerable water of condensation and it is well to use
only that which has stood in flasks long enough to show only slight
traces, although dishes may be filled with fresh agar and allowed
to stand until the surface is dry and no drops of water are visible
on the under surface of the cover.

When material under investigation contains only a few scat-
tered bacteria, which may be ascertained by examination of hang-
ing drops, Petri dishes may be streaked without the necessity of
liquefying the agar; the loop is sterilized and plunged into the ma-
terial and the surface of several dishes streaked without sterilizing
the platinum during the inoculations. The first one or two may
not be freely distributed, but others will contain colonies here and
there which are pure cultures, and these may be transferred to fresh
dishes. Pure cultures will remain alive for months, and in some
cases for years, in test tubes sealed and protected with rubber caps,
or if plugged with sterilized cotton and sealed with wax (having
previously moistened the surface of the cotton with corrosive subli-
mate.) Mold destroys many cultures; it starts to grow in the cot-
ton and will often grow through it, down along the inside of the
tube for several inches, until it reaches the nutrient material. It is
well to make fresh transfers of cultures which are desired to be
kept, at least once in three weeks.

As it is necessary to cultivate bacteria in the absence of oxygen,
a special apparatus is desirable, one employed for such purpose (by
Novy) is worthy of special mention, since it may be used with

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE. 81

hydrogen or the pyrogallate method for both tube and plate cul-
tures.

For very fine work, hydrogen is preferable to any other gas
for anaerobic cultures, for the reason that other gases permeate
the culture media to a certain extent and have some influence on
the growth of delicate organisms. The cost and trouble connected
with this method are too great for ordinary work, so the pyrogal-
late method is generally employed, which may be described as fol-
lows : The test tubes are put into apparatus in upright position on a

Fig. 28

wire rest, which fits in glass cylinder about two inches above the
bottom; on this wire the Petri dishes may be placed also; before
sealing, a quantity of pyrogallic acid and a 1-16 dilution of normal
potassium hydroxid, or caustic potash, are put into the bottom of
the apparatus so that the liquid will be a litle over one inch deep.
The pyrogallate formula is, one part pyrogallic acid and ten parts
of a 1-16 normal caustic potash solution. (A normal solution con-
tains about seven grammes to 125 cubic centimeters of water.) The
apparatus must be sealed quickly, and the glass stop-cock at the top
shut off, so that there will be a complete absorption of the oxygen
within the chamber. The apparatus may be placed in the incubator
or may be left at room temperature, according to the nature of the
organisms under investigation. In this manner it may be demon-
strated if a given species of bacteria is strictly anaerobic or whether
it is facultative anaerobic.

In canned goods which have soured, there are frequently found
strictly anaerobic bacteria growing along with other species which
are aerobic by nature. The can contains oxygen after every ster-
ilizing process, and this oxygen is used up by the aerobic bacteria,
and then the anaerobic varieties begin to grow, where the steriliza-
tion has not been complete. This is a common phenomenon and
explains our failures sometimes in isolating living bacteria from
cans of sour goods, where the anaerobic apparatus is not employed.
In the natural putrefactive processes going on in the free atmos-

82 CANNING AND PRESERVING OF FOOD PRODUCTS.

j phere the anaerobic bacteria depend upon the aerobes to use up all
the oxygen, while they remain dormant until there is a favorable
condition of environment for their growth.

STAINING. When living bacteria are viewed through the
microscope, in order to see them well, a 1-12 oil immersion lens
must be used and the result is not very satisfactory so far as the
size and general characteristics are concerned. If the bacteria are
motile this may be learned, but it is hard to follow an actively
motile bacillus, for it is in focus usually only an instant, and then
it is necessary to use the fine adjustment to bring it into focus
again, which often fails. Non-motile organisms are clumped usu-
ally, but owing to the great transparency of bacteria the study of
the living unstained germs is not very satisfactory.

The art of staining has enabled the bacteriologist to deter-
mine in many instances the kind and class. Many bacteria have
peculiarities in their staining properties, and these peculiarities help
the student. There are certain staining methods which fail with
some species and the staining of flagella often aids the worker in
determining the species by the number and character of the flagella
of motile organisms. There are some motile bacteria which seem
to possess no flagella, and it is thought that their motility is achiev-
ed by an undulating membrane attached to them, (I have never
seen any motile bacilli without flagella), and the absence of flagella
from the cell of a motile organism can be ascertained only by nega-
tive results in staining. Some bacteria are surrounded by a cap-
sule, which is brought out by staining. Spores are easily located
within the cells by their resistance to staining; the cell stains well,
but leaves the bright spore almost transparent within the cell mem-
brane. The spores themselves are stained by special methods and
the rest of the rod may be stained with a different colored dye,
j which produces a beautiful effect in permanent mounts.

The first step in staining is to have clean cover-glasses (cover-
glasses are either round or square pieces of glass only about i-ioo
to 1-200 of an inch thick,) which are sold in small boxes holding
half an ounce. The cover-glasses are covered usually with a fatty
substance, which is removed with difficulty. This fat is removed
by soaking a number in sulphuric acid for a clay or two, then wash-
ing with caustic soda or potash, and then further cleaned by a mix-
ture of alcohol and ammonia. (See also method of cleaning cover-
glasses described under flagella staining). It is well to keep
cover-glasses in absolute alcohol in a bottle with ground glass stop-
per to avoid evaporation. Just before using they are lifted out of
the alcohol one at a time, and dried with clean linen free from
fat, then passed quickly through a flame. If allowed to get too
hot the edges melt clown or the shape changes either concave or
convex, which is undesirable, or the glass flies all to pieces, which

PRINCIPLES OF BACTERIOLOGICAL TECHNIQUE. 83

is often the case, but may be overcome by quick work. A small
drop of distilled water is placed in the center of the glass, and a
small speck of material containing germs is mixed with the drop,
care being taken not to have too many germs; the drop is then
evenly spread over the whole surface, and if the glass be clean this
will be done easily. Should the fluid collect in small droplets, it
indicates that the cover-glass is not clean, and the process of clean-
ing the cover-glass must be gone over again so that the fluid will
spread evenly over the entire surface. For convenience in handling,
the cover-glass is held in a small forceps. (One devised by Novy
for this purpose is very good.) The fluid is allowed to dry onto
the glass by evaporation, or may be hastened by waving in the
air. When absolutely dry it is fixed by passing through the Bunsen
flame three times quickly, keeping specimen side away from actual
contact with the flame. The bacteria are thus firmly fixed on the
glass, so that they will not wash away when the staining is done.
A small drop of water is then placed on the specimen side, and al-
lowed to spread over the surface, and then the glass is flooded
with an aqueous solution of dye, such as carbol fuchsin, methylene
blue, gentian violet, Bismarck brown, etc. The glass holding the
rounded drop of color is held about three inches over the flame
and heated until vapor is seen to rise, and this is maintained for
several minutes, care being exercised to avoid actual ebullition. It
is not a good plan to force the staining by too much heat ; the best
results are obtained by gentle heating for a longer time, and if
the stain is allowed to cool before using water to wash excess
away, the danger of cell shrinkage is minimized. After washing
off the excess of stain, a few drops of dilutee! alcohol will clear
up the field, but it must be washed off at once; then take a clean
glass slide and place the cover-glasses on it, specimen side down,
removing excess of water by filter paper, and dry the upper sur-
face ; now place a small drop of cedar oil on center of cover-glass ;
put slide under microscope; bring down 1-12 objective until it
touches the oil and bring into focus with fine adjustment. If the
specimen is all right the cover-glass may be floated off by water
and allowed to dry in air or by touching edge to filter paper, wav-
ing in air, etc.. and when dry it may be cleared by flooding both
sides with xylol, then turned edge down on filter paper and finally
held about twelve inches above flame until dry. To mount cover-
glass, take a clean slide, warm over flame until all moisture is
forced away, then place a small drop of Canada balsam dissolved
in xylol in the center. (Xylol balsam is put up in tubes all pre-
pared for use. A small drop may be squeezed out of the tube onto
the slide, experience teaching just the required amount.) The
slide is again held over flame to drive away all mosture, and the
cover-glass is also warmed and placed, specimen side down, upon

84 CANNING AND PRESERVING OF FOOD PRODUCTS.

the drop of balsam, and may be pressed down firmly by laying a
sheet of filter paper over it, or by using a cork of the same diameter.
There should be only enough balsam to fill up space, but it often
happens that some excess will be squeezed out; this will harden
eventually and will cause no inconvenience unless it is too excessive,
in which case it may be removed with a little xylol and clean linen.
Many microscopists have trouble in obtaining clear work on
account of moisture on the slide or cover-glass during the mounting,
so I wish to call particular attention to the perfect drying of both
slide and cover-glass before using the xylol for clearing.

METHOD OP OBTAINING AND STAINING CONTACT
SPECIMENS. This method is used to show the "Swarming Is-
lands" of such bacteria as Proteus Vulgaris, Proteus Mirabilis and
Proteus Zenkeri, which are shown in plates.

The colonies are grown on gelatin, and when the bacilli begin
to swarm and branch off from the parent colony a cover-glass is
dropped carefully over a colony and gently pressed; it is then
lifted straight up, avoiding any lateral movement, and dried in the
air, then stained as directed in the ordinary method. If the colonies
show liquefaction, contact specimens cannot be made.

GRAM'S METHOD OF STAINING.

This method of staining is used to differentiate the species.
There are a great many bacteria which do not retain the stain,
while others having great resemblance take the stain readily. The
age of the culture and the medium upon which it grows have some-
thing to do with the results.

METHOD.

1. The cover-glass specimen is stained for a few minutes with
Ehrlich's anilin-water gentian violet. (Anilin oil=4 c.c.-j- water
100 c.c. + n c.c. of concentrated alcohol solution of gentian violet.)

2. Wash with water and use Gram's solution of iodin (iodin
crystals I gramme+iodide of potash 2 grammes -(-water 300 c.c.)
until the stained surface blackens, which requires about half a min-
ute.

3. Wash with alcohol until excess color is removed. Then the
specimen may be examined under the microscope to ascertain if
the bacteria have taken the stain.

METHOD OF STAINING TUBERCLE BACILLI.

The tubercle bacilli are found frequently, and often in large
numbers, in fresh milk and also in butter. The method of staining
here given is used to demonstrate the bacilli from phthisical pati-

PRINCIPLES OF BACTERIOLOGICAL TECHNIQUE. 85

ents and is applied to the sputum, which is carefully spread over
the surface of a cover-glass, air dried and fixed in flame as in ordi-
nary method. Tubercle sputum is easily obtained, and the stain-
ing of the bacilli affords excellent practice for the beginner.

For examining milk and butter a centrifugal machine is used
to obtain a sediment, which is more apt to show the presence of
consumption germs than a small quantity taken at random.

The suspected milk is put into the bottles and the machine is
used for a few minutes, the fluid is poured oft" and the cover-glass
is spread with some of the sediment. If butter be suspected, a
small quantity is put into a test tube about three-fourths full of
water, which is then heated in water to melt the fat. The tube is
thoroughly shaken and put on ice to solidify the fat, after which
the fluid is put into the centrifugal machine, the same as described
for milk, and a cover-glass spread is made of the sediment. The
cover-glass thus prepared will contain too much fat, so it must be
air dried and heated slightly, and laid in a mixture of ether and
alcohol (i to 3) for a few seconds, then removed, air dried, fixed
in flame and stained as follows :

The cover-glass is flooded with Ziehl-Neelsen's carbol-fuchsin
(fuchsin i gramme+ alcohol 10 c.c.+ water 100 c.c. -{-carbolic acid
5 grammes), and heated over flame until vapor arises and set to
one side. Repeat three or four times ; wash off excess of stain with
water and decolorize with a twenty per cent, solution of sulphuric
acid and wash acid off with water. If still too red, use sulphuric
acid again. When washed the specimen should be pink. The
cover-glass is then flooded with Loeffler's methylene blue (concen-
trated alcohol solution of methylene blue 30 c.c. + watery solution
of caustic potash i : 10,000 TOO c.c.), and heated for a few sec-
onds, then washed under the water tap until all excess color is re-
moved. The tubercle bacilli will be stained a deep red, and the
surrounding field will be blue, which makes a beautiful contrast.

Since one-seventh of the population of the world die from con-'
sumption, this disease germ is most interesting for study and bac-
teriological investigation. It is transmitted from one person to an-
other in various ways, by breathing 1 particles of floating matter
containing the bacilli in the homes of consumptives, in public con-
veyances and buildings, and in articles of food, such as milk and
butter. It is not hereditary. The germs are destroyed at 2I2F.,
and there is danger only in such foods as are consumed in an un-
cooked state. Pasteurization destroys them in milk, and this meth-
od of treating milk and cream intended for butter-making is to be
highly commended.

86 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Tuberculosis, Koch (1882)

TUBERCLE BACILLUS.

Origin. In tuberculosis of mammals; in lupis vulgaris. The bacillus
of chicken tuberculosis is distinct from that of mammals.

Form. Rather long, very narrow rods, smaller than the diameter of
a blood cell. Are sometimes beaded. May be straight, but more fre-
quently are slightly bent or nicked; distinctly rounded ends. Usually
single, but sometimes forms short threads of three to six cells. It is fre-
quently found in small bunches in the sputum, tissues, etc. It rarely
occurs in branching form and with club-shaped ends.

Motility. Is not motile.

Sporulation. A number of bright bodies are frequently seen in the
cell, but cannot be considered true spores. The bacillus is resistant to
heat, dessication, acids, putrefaction, etc., in a relatively high degree.

Oxygen Requirements. It is a facultative anaerobe. Requires free
access of oxygen for growth.

Temperature. Grows best at 37-39 C. Slight variations above or be-
low this temperature will stop the growth. Will not grow at ordinary
temperature.

Behavior to Gelatin. No growth at ordinary temperature. Does not
peptonize blood-serum.

Infection. Takes place ordinarily along the respiratory tract Inha-
! lation tuberculosis. It may occur through wounds Inoculation tubercu-
losis, also through food Intestinal tuberculosis. The bacilli introduced
into the intestines may localize in distant parts of the body.

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE. 87

METHOD OF STAINING SPORES OF SPORE-BEARING BACILLI.

The spores when free, or when fully formed within the bacilli,
are very difficult to stain, but by heating the cover-glass specimen
five or six times with carbol-fuchsin or gentian-violet, they will
take the stain. The rods will decolorize in one minute in a 3 per
cent, solution of HCL alcohol, and after washing they may be
stained with methylene-blue, in contrast to the spores if fuchsin
was used, or if the spores were stained with violet the rods may
be stained with Bismarck-brown.

Plate 17 Tubercle Bacilli

Tubercle Bacilli. Photomicrograph from a Coverglass Specimen obtained from sputum. Mag. X 1,000.

*THE DEMONSTRATION OF THE FLAGELLA OF MOTILE BACTERIA AND
A SIMPLE METHOD OF MAKING PHOTOMICROGRAPHS.

Methods Worked Out by the Author.

Motile bacteria should be represented in illustrations just as
they are naturally. The photomicrographs usually displayed in
works on bacteriology do not as a rule represent motile bacteria
as they should be. I. therefore, took up the study of staining these
organisms and endeavored to discover a method which would give
good results with all kinds of bacteria and I made a comparative
study.

I have always obtained the best results with all species of bac-
teria, excepting the anaerobic, by streaking the surface of 2 per
cent, agar in Petri dishes, and the streaked culture should always

*From my address delivered before the Society of American Bacteriologists,
at Philadelphia, Dec. 27, 1904.

88 CANNING AND PRESERVING OF FOOD PRODUCTS.

be made from the young growth in bouillon and never from an agar
or gelatin transfer. I usually inoculate a tube of bouillon the night
before and streak the surface of the agar early on the following
morning and then place the dishes in optimum temperature, so that
I may get the most rapid growth possible. I find that 2 per cent,
agar is preferable to that of less per cent., because the bacteria
as a rule do not collect much debris from the culture media. Bac-
teria differ widely in the number and character of their flagella.
Some are peritrichous, having large numbers growing out from
all parts of the cell; some are lophotrichous, having a bunch of

Plate 18 Typhoid Bacilli, Flagellated
Magnified 1,000 diameters.

flagella at one end; some are amphitrichous, having a flagellum
at either end; some are monotrichous, having a single terminal
or polar flagellum. The flagella of different organisms vary in char-
acter; some are extremely fine, so delicate that they stain with
difficulty; some are long and wavy; others are short and may be
almost straight. The anaerobic bacteria possess flagella which are
extremely curly, and it is possible to determine from the character
of its flagella whether an organism is an anaerobe or an aerobe.
Many motile bacteria produce spiral bodies which are termed "Giant
Whips" by Novy; some of these will reach ioo/* in length.

I found that the methods for flagella staining described by the
old authors had to be modified considerably in order to get good
results. By constant practice and very hard work, often prolonged
into the small hours of the morning, I finally succeeded in my ef-

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE. 89

forts. I found there were six general classes of bacteria, each dif-
ferent from the other, in its manner of growth, making it neees :
sary to treat each class in a different manner. I divided the motile
bacteria into six classes for staining purposes :

FIRST bacilli which grow like the streaked culture of the
Typhoid, such as Typhoid and Colon.

SECOND bacilli which produce wrinkled or folded
growths, such as Mesentericus fuscus.

THIRD bacilli which send out a thin, almost transparent
growth over the surface of the agar, such as Bacillus Subtilis and
Bacillus Megatherium.

Plate 19 Bacillus Mesentericus Fuscus, Flagellated

Magnified 1,500 diameters.

FOURTH bacilli which produce slime, such as Bacillus Vul-
gatus and Bacillus Viscosus.

FIFTH bacilli which produce pigments, such as Bacillus
Prodigiosus and Bacillus Cyanogenus.

SIXTH anaerobic bacteria, such as Bacillus Tetanus, Oede-
ma and Symptomatic Anthrax, etc.

90 CANNING AND PRESERVING OF FOOD PRODUCTS.

MANNER OF MAKING SUSPENSIONS IN WATER.

(1) Bacteria resembling Typhoid streak cultures have very
young and actively motile bacteria on the periphery of the growth.
From this the material is taken and transferred to a large drop or
two of distilled water which has previously been boiled. The plati-
num loop should be made from very fine platinum wire, only about
half the size of the loop used for general purposes. This fine loop
will gather sufficient material without taking up any of the agar.
The material usually clings tenaciously to the loop, but may be
liberated by the aid of another platinum wire, if care is exercised.
The bacteria are then allowed to disseminate spontaneously
throughout the drop of water, so that the finest specimens will
swim to the outer edges from which the cover-glass preparation
is made. Bacteria which have few flagella and those whose flagella
have been broken will remain near the center.

(2) Preparations made from bacteria which produce wrink-
led or folded growth are made before the wrinkled growth is
formed. In order to get a good preparation from this group of
bacteria the agar should be streaked in the morning and then care-
fully watched for the first appearance of growth and from this a
satisfactory preparation can be made.

(3) The thin, transparent, spreading growth is one of the
best for demonstrating flagella. This growth is almost invisible
and is composed of very young and actively motile bacteria. In or-
der to get a good preparation from this a curved platinum wire
is used to gently collect the bacteria en masse and then the small
loop is employed to make transfers to the distilled water.

(4) The slime-producing bacteria are very difficult for the
demonstration of flagella. The slime collects between the flagella
and the mordant fixes the slime as well as the flagella, so that the
stain completely covers the delicate organs of locomotion. I found
that this slime could be precipitated by shaking a water suspension
with chloroform. A very young growth of the organism is used
and transfers are made to about i c.c. of distilled water in the test
tube until the water is made very cloudy. The slime increases the
cloudiness and this is necessary in order to have a sufficient number
of bacteria to make a fine preparation. This cloudy suspension is
then shaken with chloroform, which seems to cut away the slime
from between the flagella ; then the cover-glass preparation is made
from the water above the chloroform.

(5) Bacteria which produce pigments soluble in chloroform
are treated in the same manner. Those whose pigments are soluble
in water and not in chloroform are more difficult to stain. I usually
hold the cover-glass under the tap after fixing the preparation in

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE.

Plate 20 Bacillus Subtilis, Flagellated
Magnified 1,000 diameters.

3 /U ,

Plate 21 Bacillus Mesentericus Vulgatas, Flagellated

Magnified 1,200 diameters.

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE. 93

the flame previous to adding the mordant. In this way much of
the soluble pigment is removed.

(6) Good suspensions of anaerobic bacteria are the most dif-
ficult of all to obtain. Bacteria which are imbedded in stab cul-
tures do not make good preparations, because the agar and debris
cling tenaciously to the flagella. It is extremely difficult to get
a good surface growth of obligative anaerobes, because it usually
requires two or three drops of a young bouillon culture for surface
inoculation and when the growth appears the surface is covered
with the old, partially dissolved cells and free spores. Still, some
very fine preparations can be made from the surface of the culture.
The best results are obtained as follows : The medium is 2 per
cent, glucose agar in slants and the inoculation is made back of the
slant between the agar and the wall of the tube. I slide the needle
down back of the slant and let it fall forward ; I introduce two or
three drops of a young bouillon culture and then replace the agar.
By excluding oxygen and maintaining a blood temperature for
thirty-six hours, a fine growth of bacteria usually appears between
the agar and the wall of the tube and beautiful preparations can be
made from this. Many rods containing spores still retain a full
equipment of flagella.

CLEANING THE COVER-GLASSES.

I prefer the No. i round cover-glass, which when new are cov-
ered with a thick, greasy substance quite difficult to remove. Cover-
glasses used for the demonstration of flagella must be absolutely
clean, and this is a most important feature. For removing the
grease they are covered with suphuric acid and allowed to stand for
one day. The sulphuric acid is poured off and they are then cov-
ered with bichromate of potassium and allowed to remain in this for
several hours. This acid is then poured off and the cover-glasses
are washed with distilled water and transferred to a jar containing
absolute alcohol, where they remain until ready for use. A single
cover-glass is removed with clean forceps from the alcohol, trans-
ferred to a piece of clean, well-washed linen and dried without
touching it with the fingers. The cover-glass is then taken in the
forceps and passed several times through the Bunsen flame, so
that every particle of fat or grease is removed, and it must appear
clear and free from blemishes. Many cover-glasses are lost after
heating in the flame, particularly if there are any currents of cold
air through the room, but since the perfect condition of the cover-
glass is so important the loss of two or three is immaterial.

94 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Oedematis Maligni, No. 2, Novy (1893)

Origin. Obtained from guinea-pigs which had been inoculated with
milk nuclein obtained from casein by digestion with artificial gastric juice.

Form. In the animal body it is usually found in single rods, four to
five times as long as wide ; also occurs in short threads. On artificial
media the rods are straight or bent; peculiarly twisted threads are some-
times formed. The contents are frequently granular, showing a bright
body at one end.

Motility. A slight, swaying motion, which is not always present.
Possesses lateral flagella, and gives rise to giant whips 40 to 72 microns
long in pure cultures as w r ell as in the animal.

Sporulation. Has riot been observed.

Anilin Dyes. Stain readily. Gram's method may be used.

Growth. Depends upon vitality. Grows rapidly when taken from an
animal.

Plates. On glucose agar at 37 good colonies will develop in two
or three days; these have irregular, fibrillated border, and frequently de-
velop gas bubbles. Giant whips are sometimes found.

Stab Culture. Grows only in the lower part of the tube. In glucose
agar properly alkaline, a distinctly visible growth develops along the
line of inoculation ; gas is produced which soon tears apart the agar. The
cultures soon die out.

Streak Culture. Grows on glucose agar only when oxygen is com-
pletely excluded ; grows in the form of a white film, spreading over the
surface. Involution forms develop on acid agar.

Bouillon. A fine growth is developed which settles to the bottom as
a loose, flocculent sediment in twenty-four hours; the liquid above be-
coming clear.

Glucose Gelatin colored with litmus. Liquefies and produces acid.
The litmus is reduced and turned red.

Oxygen Requirements. It is an obligative anaerobe. Will grow in
vacuum hydrogen, nitrogen, carbonic acid and illuminating gas.

Temperature. Does not grow below 25 C. Grows best at about 39
Will withstand freezing for twenty-four hours.

Behavior to Gelatin. Liquefies.

Aerogenesis. Produces gases in alkaline media. Forms volatile acids,
as butyric acids, etc., in artificial cultures and also in the body of rabbits.

Attenuation. Cultures lose their virulence when exposed to light or
left in hydrogen. Can be kept in the dark or by passing through animals.
Lost virulence may be restored by inoculation with a mixed culture con-
taining Proteus vnlgaris.

Immunity. Is not produced by non-fatal inoculation, or by old
weakened cultures, or by the serous exudate of the pleural cavity.

Pathogenesis. Subcutaneous injection of -/4 c. c. of hydrogen bouillon
cultures will kill guinea-pigs, white rats, white mice, rabbits or doves,
in twelve to twenty-four hours. Marked subcutaneous edema are present.
Serous exudates in thoracic and abdominal cavities. Cover-glass prepara-
tions made from subcutaneous tissue or serous surfaces usually show
very large numbers of bacilli ; giant whips are also frequently present, be-
ing visible as colorless spirals.

Diagnosis. It is readily distinguished from symptomatic anthrax and
malignant edema by morphological characteristics.

PRINCIPLES OF BACTERIOLOGICAL TECHNIQUE.

Plate 22 Bacillus Tetanus, Flagellated

Magnified 1,200 diameters.

Plate 23 Bacillus of Malignant Oedema

Magnified 1,500 diameters.

PRINCIPLES OP BACTERIOLOGICAL, TECHNIQUE. 97

PREPARATION OF THE STAINING AGENTS.

The fixing agent is mordant and the stain is carbol gentian
violet or preferably carbol fuchsine.

THE MORDANT.

2 grams dessicated tannic acid.

5 grams cold saturated solution ferrous sulphate (aqueous).

15 c.c. distilled water.

i c.c. saturated alcoholic solution of fuchsine.

The tannic acid is dissolved in the water first, by the applica-
tion, of gentle heat; then the ferrous sulphate and then the alco-
holic solution of fuchsine are added.

To these ingredients, I have always found it advisable to a.dd
a certain amount of sodium hydroxid, a i per cent, solution, varying
from ]/2 to i c.c. The best grade of filter paper is used for filter-
ing the mordant, and there should be left a heavy precipitate. Af-
ter filtering, the color of this mordant should be of a reddish-brown
hue, not clear, but somewhat cloudy, and this mordant must be
used within five hours after it is made. After that time, it loses its
staining power. This is indicated by its gradual clarification and
darkened color. It gives the best results when strictly fresh, and
accomplishes its work in a much shorter time, so that very little if
any heating is required when it is placed on the cover-glass prep-
aration.

CARBOL FUCHSINE.

Take about one gram of granulated fuchsine (not the acid
fuchsine), put it in a bottle, and pour over it about 25 c.c. of warm
absolute alcohol. Shake vigorously, and let it stand for several
hours before using. The carbol fuchsine is made by diluting the
saturated alcoholic solution four or five times with a 5 per cent,
solution of carbolic acid. Carbol fuchsine should be freshly made,
heated and filtered before using.

Every organism differs from other organisms in its manner
of absorbing the stain, so that some experimental work is necessary
to determine just how the stain should be applied. In a general
way we proceed as follows : A small loop full of the clouded wa-
ter, obtained as described in the first part of this article, is trans-
ferred to the cover-glass and gently spread over as large a sur-
face as possible. Care must be exercised in spreading the drop. I
usually carry the drop around the surface without touching the
glass with the loop. In this way the surface is moistened, and the
loop does not tear off the flagella. A confluent spread does not
give as good satisfaction as a streak spread with a small space be-

CANNING AND PRESERVING OF FOOD PRODUCTS.
Bacillus Anthracis Symptomatici,Feser and Bellinger ( 18 78)

SYMPTOMATIC ANTHRAX, BLACK LEG, QUARTER EVIL; CHARBON
SYMPTOMATIQUE (FR.) ; RAUSCHBRAND (GERM.)

Origin. Found in the subcutaneous tissue, muscles, serous exudate,
etc., of symptomatic anthrax.

Form. Rather large, narrow rods, having rounded ends; almost
always single, but sometimes are found in pairs. About three times as
long as wide. Involution forms are seen in old cultures swollen at the
ends or in the middle.

Motility. Actively motile, having lateral flagella; giant whips are
often found. Spore-bearing rods lose their motion eventually.

Sporulaiion. Spores develop near one end, which is enlarged; they
are bright and oval in form; are not formed in body until after death.

Anilin Dyes. Stain readily. Will stain by Gram's method if a strong
dye acts for some time. Spores may be readily double stained.

Growth. Rapid ; best in acid or alkaline glucose media ; attended with
strong butyric acid odor. Will not grow except under anaerobic condi-
tions.

Plates. On gelatin, irregular masses are formed surrounded by dense
whorl of threads. Gelatin is liquefied. On agar, the colonies usually ap-
pear as dense masses of threads ; they vary, however.

Stab Culture. In glucose gelatin,, growth takes place in the lower
part of the tube ; gas is produced ; contents liquefied. In glucose agar,
growth is energetic and gas is produced, the contents of the tube being
torn into several parts. Giant whips common (Novy).

Streak Culture. On glucose agar in hydrogen, a whitish, spreading
film is formed. On blood serum, growth is good; giant whips (Loeffler).

Bouillon. Is clouded; gas bubbles accumulate on the surface; the
growth settles to the bottom after several days, forming a compact, ad-
herent sediment ; liquid above remains cloudy for several days.

Glucose Gelatin, Colored with Litmus. Under ordinary circumstances,
growth develops in incubator. The litmus is reduced, then colored a
wine-red, showing formation of acid. Heavy, flocculent sediment is de-
posited on the bottom.

Milk. Coagulates casein rapidly ; does not invert starch. Grows on
potato.

Oxygen Requirements. It is an obligative anaerobe. Will grow in
hydrogen, vacuum, carbonic acid, etc. Grows in glucose litmus gelatin in
presence of air.

Temperature. Grows best at 37-38 C. Will grow slowly at room
temperature.

Behavior to Gelatin. Liquefies.

Aerogenesis. Produces gas with disagreeable odor ; gas is inflam-
mable, consisting of marsh-gas, hydrogen, etc.

Attentuation. Bouillon cultures lose their virulence soon but retain
vitality. Attenuation occurs at 42-43. Dry spore-bearing material be-
comes attenuated when heated to 80 or 100. Virulence may be restored
by inoculating animals, at the same time injecting some lactic acid. Vir-
ulence is maintained in solid media.

Immunity. May be obtained by inoculating small amounts of viru-
lent germ; by intravenous injections; by injection of heated cultures, 80
or 100 ; in active old cultures ; filtered cultures.

Patho gene sis. Young cattle, sheep, goats, guinea-pigs and mice are
highly susceptible. The horse, ass and white rat are less susceptible.
Hogs, dogs, rabbits, ordinary rats, doves, ducks and chickens are almost
immune. Death is produced in twenty-four to forty-eight hours in
guinea-pigs by subcutaneous injection. Extensive subcutaneous bloody
edema is present. Gas is present. The muscles are dark and infiltrated.

Infection. Occurs naturally by inoculation through deep wounds ;
very rarely through food. Poisoned arrows used in fishing in Norway.

Diagnosis. It is especially a disease of cattle, and not of man. It
is difficult to distinguish the bacillus from malignant edema bacillus. In
ocnlation of the rabbit is negative, threads are absent; tendency to in-
volutions. It is distinguished from anthrax bacillus by form, motility,.
by its distribution in the body and by cultural properties.

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE,

Plate 24 Bacillus of Symptomatic Anthrax, Flagellated

Magnified 1,200 diameters.

Plate 25 Asiatic Cholera, Flagellated

Magnified 2,000 diameters.

PRINCIPLES OF BACTERIOLOGICAL, TECHNIQUE. 101

tween each streak. The finest specimens for photomicrography are
obtained from the periphery of the streaks. The spreading must
be done rapidly because evaporation takes place very soon. After
evaporation takes place, there should appear very thin films along
the track of the loop. The preparation must be fixed in the flame
so that the bacteria will not wash off during the staining, but the
fixing must not be accompanied by too much heating, because the
delicate organs of locomotion are easily burned off. The Bunsen
flame should be about one inch high; the glass held by the forceps,
preparation side up, is passed down on to the flame just once and
instantly removed. The cover-glass is then ready for the mordant,
which is poured on, just enough to cover the surface without flow-
ing over the edges. I find that the Cornet forceps are best suited
for staining purposes, and if the cover-glass be held just a short
distance within the edge, the mordant or stain will not run off.
It usually happens that we are unsuccessful in demonstrating fla-
gella, if the mordant runs off, or goes on the under side of the glass.
During the steaming of the mordant, it is advisable to keep up a
rotary motion in order to avoid too much precipitation. When the
mordant is fresh, it requires only about one-half to one minute to
get sufficient staining. The mordant is completely washed off un-
der the tap, and this is done pretty thoroughly ; a small quantity of
absolute alcohol is poured onto the surafce, and this is instantly
washed off. The alcohol removes a great deal of the precipitation
which is found in cover-glass preparations, but considerable care
should be taken to wash it off quickly and thoroughly, because it
will remove the germs and flagella, if it is allowed to act only for
a short time. If the alcohol is thoroughly washed off, the water is
removed by holding the glass edgeways to a piece of filter paper.
If the filter paper is not clean, considerable dust and fiber will
be carried up on to the cover-glass, and if there is any danger of
this, it is better to finally wash the cover-glass off with the dis-
tilled water and shake off the drops which cling to the glass. Then
cover the surface with a carbol fuchsine or carbol gentian violet.
I find in nearly all cases, that fuchsine is better than violet, and
gives less precipitation, but in some cases the gentian violet brings
out the flagella more prominently. This must be fresh, however,
and thoroughly washed off after staining. We allow the fuchsine
to stand on the cover-glass for about one-half minute, being heated
just sufficiently for a thin vapor to be visible. We then heat it so
that steam is given off quite freely, but never until ebullition takes
place. Care must be used when heating the stain, because it is not
unusual to find that there is entirely too much precipitation, and
the flagella are burned off. It rarely happens that we get a cover-
glass which will be stained well all over. Usually we get only cer-
tain sections where the flagella stand out prominently, and the field

102 CANNING AND PRESERVING OF FOOD PRODUCTS.

is free from precipitation. Views sufficiently attractive for photo-
micrographing are rare. While the staining may be perfect, there
will be some defects in the germs. Some may have lost part of
their flagella, or there may be too much precipitation in the field,
or the germs may be too close together or too scattered, and the
ideal views for photomicrography are few. and it is sometimes nec-
essary to stain up several cover-glasses, before we get a fine view.
During the staining with the mordant and dye, a thin film is form-
ed all over the glass. This must not be broken up by the applica-
tion of too much alcohol, if a clear field is desired.

Some writers advocate the idea of examining the cover-glass
preparations on the slide with a drop of water under the cover-
glass, before finally clearing and mounting the specimen. I have
been unfortunate in this procedure, and on several occasions have
lost some beautiful specimens on attempting to float off the cover-
glass with water, after examination. It frequently happens that the
germs will stick to the slide and pull off, leaving graves surrounded
by beautiful bunches of flagella, so I make it a rule to mount my
cover-glass in xylol-balsam, as soon as I have finished staining. I
do this as follows :

I select very thin slides, pieces of glass about 3 inches long and
i inch wide, perfectly clear, and having no blisters. Having thor-
oughly cleaned the slide, I heat it over the flame to drive off mois-
ture, and place in the center a small drop of xylol-balsam (which is
Canada balsam dissolved in xylol, and comes in collapsible tubes).
After thoroughly drying the water from- the cover-glass after stain-
ing, I pour pure xylol all over the surface, and immediately touch
the edge to clean filter paper, and then drive off the xylol with
heat. It is absolutely necessary to have the cover-glass free from
moisture before applying xylol. (Xylol is a refined benzine).
Otherwise, a hazy appearance will be imparted to the preparation,
and this spoils it for microscopical purposes. After clearing with
xylol and drying, the drop of balsam is heated gently and the cover-
glass, preparation side down, is pressed on to the slide so that the
balsam is spread out in a thin layer between the two pieces of glass,
and the preparation is, of course, thus protected from injury. The
method for the demonstration of the flagella of different organisms
varies, as we have said. The differences which I have noticed have
been in the length of time allowed for staining with the mordant,
and the fuchsine; also the amount of i per cent, sodium hydroxid.
Great success is achieved only by careful and patient study of each
organism. It is not a difficult matter to demonstrate the flagella
of most motile organisms, but to get beautiful preparations is a
study, and requires great care in every step of the work.

PRINCIPLES OP BACTERIOLOGICAL. TECHNIQUE. 103

SUMMARY.

Culture to be made on 2 per cent, agar from young growth
in bouillon.

Suspensions in water to be made according to nature of or-
ganism.

Cover-glasses to be absolutely clean.

Mordant to be used only when fresh.

Dye to be made fresh and used while warm.

Spread on cover-glass not to be confluent.

Fixing to be done without injury to flagella.

Staining to be done without overheating.

Washing with alcohol and water without breaking the film.

Clearing with xylol after thorough drying.

Mounting in xylol-balsam without previous examination.

A SIMPLE METHOD OF MAKING PHOTOMICROGRAPHS.

A large, cumbersome apparatus is unnecessary. The camera
is about twice as long as the ordinary 4x5 camera, and the photo-
micrographs are taken with the camera in a horizontal position.
It must be a steady apparatus and the microscope stand should be
substantial and with the cone fine adjustment. Much depends upon
the objective. In order to get negatives showing a flat field with
clean definition I have used nearly all kinds of objectives, but have
found none equal to the 1-12 oil immersion objective and No. 6
compensating eye-piece made by the Spencer Lens Co. The best
plates are the isochromatic or orthochromatic swift plates, which
are correct for colors. I have found the acetylene radiant, prefer-
able to gas, oil or electric light. It is slower than electric light, but
brings out all details with wonderful nicety. The only screen I
ever use is green glass. Printing from the negatives on glossy
Velox brings out the best detail. The glossy Velox is then ferro-
plated, which makes a beautiful photograph.

104 CANNING AND PRESERVING OF FOOD PRODUCTS.

CHAPTER IV.
Decomposition Caused by Micro-Organisms

Decomposition Caused by Micro-organisms. Fermentation The-
ories. Vacuum Theory. Alcoholic Fermentation. Acetic
Fermentation. Butyric Fermentation. Lactic Fermentation.
Putrefaction. Reprocessing Leaks a Dangerous Proceeding.

The word fermentation is derived from the Latin word fermeo,
meaning to boil. The appearance of liquids in agitation due to the
vital action of micro-organisms no doubt gave rise to the word.

The word fermentation as commonly used, implies more than
the processes of decomposition accomplished by bacteria, molds and
yeasts. Micro-decomposition is perhaps a better term, since it ap-
plies directly to the breaking down processes accomplished by micro-
organisms and their enzymes (products formed) only, and does not
take in the chemical changes induced by chemicals, rennets and
animal secretions. The term embraces also the different processes
of putrefaction, which are separated by some authors, but it seems
to me that they should be considered under one head.

FERMENTATION was the term that was applied to these
processes by the early investigators, and the history of their labors
and deductions is interesting, since it shows us the difficulties with
which they were beset and permits us to see the rays of light and
truth as they are let into the darkness by the different stars in the
scientific world from the time of Leeuwenhoek down to the present.

The early investigators, a few excepted, fell victims to the
false theory of Spontaneous Generation. Needham (in 1745)
founded a demonstration of this theory on his failures to preserve
meat juices by boiling in flasks, claiming that "infusoria" were
spontaneously created from the juices themselves.

In 1765 Abbe Spallanzani took the opposite stand, claiming
that if air, which had been exposed to fire, were admitted to flasks
containing meat extracts, the "animalcules" would not develop. In
1836 Franz Schultz conceived the idea of filling the flasks with
air filtered through sulphuric acid and potassium hydroxid, which
gave him encouragement as an opponent of the spontaneous theory.
The other side claimed that a chemical change in the air was made
by such experiments which made it impossible for the animalcules
to hatch from the vital principles of the infusions. They also

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 105

found that the methods referred to were not reliable and that micro-
organisms would make their appearance in many cases. Thus the
study of fermentation and its causes began to occupy the attention
of investigators. In 1862 Pasteur published his researches on fer-
mentation and Von Ljebig still opposed him with the theory of
spontaneous generation. Then Tyndall came forward with his ab-
solute proof that micro-organisms did not develop from inorganic
protoplasm (elementary compounds), but that they developed only
as they found admittance through the atmosphere and that if in-
fusions were sterilized fermentation could not possibly take place.
By this intermittent heat process he sterilized all kinds of liquids
and solid food substances and gave the opposition such a blow that
the ''spontaneous" theory fell.

The theory is only unproved, however, since all must admit of
a beginning of all life. That the beginning of a species is due to
a creative power is probably the best way of disposing of the ques-
tion; at what time we cannot say; whether it is still going on we
cannot say; but there is evidence that such is the case.

There are several kinds of decomposition which cannot be as-
cribed to the action of micro-organisms which the word fermenta-
tion would include. There is a spontaneous decomposition of sugar
in vegetable and fruit cells, which when kept in a pure and un-
contaminated condition, liberate carbonic acid gas CO 2 , and form
alcohol in appreciable quantities. This is no doubt due to
the life of the fruit itself, which is living protoplasm, and
when seeds are present, vital principles are therein contained
which have the power to decompose the sugar in the fruit or vege-
table cells. It is a curious fact that when a whole tomato is heated
in a flask to the boiling point, after a lapse of time it will be found
quite devoid of sugar so far as taste is concerned. Quite a liberal
quantity of gas will be liberated also, and when the seeds are ex-
amined carefully the gelatinous envelope will be found perfect as
before heating and the seeds are capable of germinating when
planted. The decomposition takes place without the vital activity
of micro-organisms. The experiment may be made by anyone in-
terested by placing a perfectly sound ripe tomato in a thin glass
jar and melting the top down to a narrow neck by means of a blow
pipe, (the skin of the tomato should be washed off with a solu-
tion of bi-chlord of mercury). This narrow neck may be stuffed
with sterilized cotton and the flask held over the flame just long
enough to permit steam to flow freely through the cotton. A bent
tube may be fastened with rubber over the neck of the flask and
the end submerged in a dish of water. To measure the escaping
carbon dioxid, a bottle with water is inverted over the end of the
tube under water. < As fast as the gas is evolved the water is ex-
pelled from the bottle, but the process is slow.

106

CANNING AND PRESERVING OP POOD PRODUCTS.

I have investigated a number of cases of so-called spring bot-
toms in cans of fruit, especially California fruits. Cases of canned
fruit are frequently found where the bottoms of the cans spring,
showing that there is no vacuum in them and quite a quantity of
gas, sufficient to cause the bottom to spring out when pressed in
by the hand.

Fig. 29

In some cases I have found wild yeasts to be the cause, but
more frequently the cans are quite free from bacteria or fungi of all
kinds. This led me to the conclusion that there was decomposi-
tion going on from a different cause, and after experimenting I
found in some cases, after a few months that the cells of the canned
fruits were actually losing sugar and that considerable carbon di-
oxid was being set free. After applying heat sufficient to kill the
cell life of such fruit, the phenomenon is no longer observed. Can-
ned fruits will therefore undergo spontaneous decomposition if suf-
ficient heat is not employed in the sterilizing process to destroy the
life of the cells. The fruit flavor suffers to some extent from the
extended sterilization, but the trouble and loss is avoided. One
other fact deserves mention in this connection and that is the tem-
perature which develops spring bottoms. If the cans are stored
in a temperature of 40 to 50 F. and opened before being allowed
to reach a warmer temperature, even the underprocessed fruits will
be found to be free from partial decomposition. It usually hap-
pens that the trouble is experienced after the cases are brought out
for sale in the early summer, just before the fruit season opens.
Wholesale grocers who buy heavily in the fall and store the goods,
usually experience some trouble when the cases are brought out in
warmer weather for the trade.

There is another cause of decomposition, and that is the influ-
ence of light on canned goods, particularly foods canned in glass.
This is true of foods containing tartaric acid, glucose, lactose and
maltose, etc., especially if the foods are faintly alkaline or if alkalies

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 107

are present even in small quantities. The action of sunlight on ex-
posed solutions containing tartaric acid may be expressed by the
following chemical equation :

C 4 H 6 O 6 + 30 = 2CH 2 O 2 + 2CO 2 + H 2 O.

Tartaric acid + Oxygen = Formic acid + Carbon dioxide +
Water.

Glucose and lactose have been found on exposure to sunlight
in hermetically sealed packages to break down and form alcohol and
carbon dioxid, or just the same fermentation that is caused directly
by the yeast plants (Saccharomyces). The same two substances
may yield, in the presence of lime, lactic acid and carbon dioxid,
or a fermentation corresponding to that produced by the bacteria
which cause the souring of milk. Thus maltose is broken up, and
yields dextro-lactic acid; levulose yields levo-lactic acid, and invert
sugar will yield an inactive acid, when polarized.

A word of advice to canners of food products in glass might
be opportune in this connection. Wrap your glass goods well, and
in_each case put cards requesting the retailer not to remove the
paper when he places his goods on the shelf. All such goods should
be neatly wrapped and have labels on the outside sufficiently at-
tractive for the shelf. Goods unwrapped for show windows should
be sold very soon on account of the danger of chemical changes
noted above.

The word fermentation has a wide meaning, in fact it is a
word to which various definitions have been given not in accord
with its root meaning, and it is made to embrace all such transfor-
mations and decompositions as we have just described, so we return
to the word micro-decomposition as one which defines the changes
produced by fungi directly.

Bacteria molds and yeasts are nutrient food substances to build
up cell protoplasm, and this is followed, or there goes on at the
same time, an excretion of waste materials which have received the
names of enzymes and toxins. There are formed at the same time
various acids and chemical compounds as a result of the disturb-
ances caused by the utilization, by bacteria, of certain elements such
as carbon, oxygen, hydrogen and nitrogen, which are torn from the
molecules containing them, thus setting free other atoms which unite
to form those products of decomposition. To make this clear to
the reader not familiar with chemistry it may be explained thus :
A molecule is the smallest body conceivable which retains the iden-
tity of the substance, and this molecule is formed by two or more
atoms or elements. An atom is an element. The atoms are united
to one another in certain relations which form the different sub-
stances with which we are familiar ; thus alcohol is expressed by its
molecular symbol C 2 H O, which means that two atoms of carbon,

108 CANNING AND PRESERVING OF FOOD PRODUCTS.

six atoms of hydrogen and one atom of oxygen are united. Now
if a fluid containing a limited quantity of this alcohol (less than
15 per cent.) is planted with the acetic acid bacteria in the presence
of atmospheric oxygen, the germs will use from the alcohol two
atoms of hydrogen and from the air two atoms of oxygen, and the
result is that the alcohol is changed into acetic acid and water thus :
C 2 H 6 O + O 2 = C 2 H 4 2 + H 2 O.
Alcohol + Oxygen Acetic acid + Water.
Substances undergoing micro-decomposition usually contain
various species of bacteria and the chemical compounds produced
are often very complex for the reason that each species may be
transforming the same substance into characteristic compounds, and
the acids and compounds formed by one species may be attacked
and changed by a different species into different compounds. For
instance, the yeast plants may be producing alcohol by their action
on glucose, and at the same time the acetic acid group will seize on
the alcohol produced and convert it into acetic acid, and this acid
may be attacked by still another species and converted into car-
bonic acid and water. Jn order to study with accuracy the_com-
pounds formed by a given species it is evident that pure cultures of
that species must be obtained and grown in a favorable nutrient
medium. The separation of pure cultures is comparatively easy by
the methods established by Dr. Koch of growing them in solid media
such as gelatin and agar, which confines the different species to
isolated positions where they may be transplanted to other media
in unmixed cultures.

There are usually several products resulting from the vital
activity of a given species, thus the yeast plants produce alcohol,
carbonic acid, succinic acid, glycerin and some volatile acids. There
are many varieties of yeast plants which produce these products in
varying quantities; some species yield very large amounts of alco-
hol and are specially cultivated for brewing, baking, etc. The
products elaborated by them depend largely upon the material in
which they are growing, and this is true of all bacteria as well.
Vital activity goes on as long as fresh material is added until a
< certain per cent, of waste product is produced, when they cease to
: perform *their functions ; then they become dormant or actually die
under the influence of the chemicals formed during vital activity.
Thus the yeasts will multiply until about 15 per cent, of alcohol
is produced. In addition to the products mentioned above the
yeasts or saccharomyces produce an enzyme which is a soluble fer-
ment capable of producing alcoholic fermentation after the germs
are dead, if placed in fresh nutrient media. There are a number of
molds which produce alcohol and various acids when submerged
in fermentable materials. Oxygen is required in large quantities by

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 109

the molds and when this is cut off by excluding the atmosphere,
they seize the oxygen which is in combination and a true fermenta-
tion, resembling that of yeasts, is produced. The free admission of
atmospheric oxygen lessens the fermentation, since this requirement
is more easily appropriated than that which is in chemical combi-
nation. The fermentation will be accomplished completely in a
longer time, however, since the evolution v of gas formed cuts off
the supply of atmospheric oxygen and the chemical combinations
are broken down for their supply. The vacuum therefore is a/
good condition for alcoholic fermentatioli. Multiplication is not soj'
prolific but fermentation is more violent and considerable heat is
generated, due to the breaking up of molecules and the formation
of new chemical compounds. Alcoholic fermentation was formerly
allowed to go on slowly for months in the breweries, but the process
has been greatly shortened by the vacuum process. The vacuum [>
pumps are set to work and the oxygen and gases are pumped away
from the fluids, thus compelling the yeast to break up the sugar
more rapidly, for their supply of oxygen.

A great many bacteria which grow naturally and luxuriantly
in the presence of air, are thus enabled to cause more violent fer-
mentation when air is excluded or when they are compelled to grow
in vacuo. Thus^ we seejthat a vacuum has no value as a means
of preventing fermentation. In canning fruits and vegetables in
tin cans a vacuum is desirable, not for the prevention of fermenta-
tion but to cause the ends to draw in after the sterilizing process.
During this process the ends of tin cans become bulged and unless
a vacuum is present, after cooling they draw in very slowly or not
at all. The vacuum is produced by heating the contents before
finally sealing the cans or by mechanical means, the power depend-
ing upon the heat and fullness of the cans. The expansion of fluids
is greatest at or near the boiling points and on cooling there is
a corresponding contraction. When cans are not filled full and the
contents are quite hot the vacuum formed on cooling has great
power, often causing the cans to collapse. The vacuum may be
regulated by attention to the heat and fullness of the can. A tem-
perature of 1 80 F. and filling as full as possible will produce a
vacuum of sufficient power for all practical purposes. The vacuum
has value in the detection of swells ; cans which do not draw in are
likely to be either leaks or swells. In this connection I want to
call attention to the misrepresentations of certain manufacturers of
vacuum machines. Recently a circular reached me giving glowing
accounts of a machine capable of sealing in vacuo thousands of
cans daily, doing away entirely with the sterilizing process, and
claiming great saving in steam and labor and the preservation of
natural flavors. The whole process was described, which consisted

110 CANNING AND PRESERVING OF FOOD PRODUCTS.

Saccharomyces Cerevisiae

Origin. Beer or bakers' yeast; also found in the air.

Co lor. White.

Form. Cells spherical or egg-shaped 8-io/x broad ; they are colorless,
and have a homogeneous protoplasm when actively growing. Granules and
vacuoles develop later. Zoogleal masses may be formed, owing to a gela-
tinous exudate. The cells are sometimes single, sometimes they have
several buds ; long, branching forms are found at times, especially above
30.

Motility. Is not motile.

Sporulation. Several spores form usually. These may be double
stained. They develop between 11 and 73 c.

Anilin Dyes. Stain readily, as does also Gram's method.

Growth. Thick white growth, which is particularly abundant on
glucose media and in wort.

Gelatin Plates. The colonies are small, white, opaque, circular in
shape, very coarsely granular and slimy.

Stab Culture. There is a thick white growth on the surface. No
growth in lower portion.

Streak Culture. On agar and on potato a thick, somewhat raised,
white growth is formed.

Temperature. Fermentation takes place most rapidly between 14
and 18 C., as an upper yeast.

Behavior to Gelatin. Does not liquefy.

Aerogenesis. A ferment, invertin, is formed which changes cane-sugar
into glucose. The latter is then changed to carbonic acid and alcohol
(4-6%) by another ferment (zymase). Does not ferment lactose.

Pathogenesis. No effect on animals. A catharrhal condition may be
produced in the alimentary tract by a large amount.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. Ill

Plate 27

Saccharomyces cerevisice, showing budding cells. Potato culture, x 1000.

Saccharomyces cerevisice. Culture on plaster service. Stained with carbol-fuchsin and methylene-blue. x 1000.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 113

of putting raw fruits, vegetables, meats, etc., in patent cans, which
were run into the vacuum machine where the air was completely
exhausted and the sealing was done in vacuo. I wrote these parties,
requesting a detailed account of their process, for I supposed that
there must be some sterilizing process connected with it, but to my
astonishment they claimed that the vaccum produced was all that
was necessary. There are a number of canners who look upon a
vacuum as a necessary condition. The fact is, however, that a
vacuum is one of the best conditions for decomposition when cer-
tain species of living bacteria and spores are present.

TH VACUUM THKORY.

There seems to be such a widespread misconception of the true
value of a vacuum in canned goods that a careful study of the
theory may not be out of place at this time. Occasionally new ma-
chines are advertised for packing all sorts of goods by the "vacuum
method," the advertisement reading that goods are superior in flavor
and require less cooking, perhaps none, if this or that method is
employed. In years gone by, nearly every packer believed that a
vacuum in his cans was absolutely necessary for perfect keeping
of the goods. The method generally adopted for obtaining the
vacuum was to heat the cans in boiling water with vent holes
open; the cans were then taken out and the holes were soldered or
"tipped," after which the cans were ready for sterilization or the
final process. Another method was to seal the cans completely;
then they were given five or ten minutes boiling, after which each
can was punctured with an awl, thus permitting the steam and
gases (if any were present) to escape; then the awl holes were
quickly closed prior to the sterilizing process. This method was
called venting. The object of these two methods was two-fold,
viz., to drive off any gases present and to expand the contents by
heat, so that a vacuum would form by contraction after cooling.
Another method which is used largely today, is to heat the goods
before filling, then the cans are sealed while hot, and when they/
are cooled off after sterilization a vacuum is necessarily produced
by the physical law of contraction.

It is very convenient and necessary that a vacuum be formed
in tin cans so that the ends will draw in after the sterilizing pro-
cess. It would be impossible to drive the ends back in some cases
(depending, of course, upon the goods) unless this vacuum were
formed. There is one exception, that is, cold packed tomatoes ; but
this cannot be called a true exception, because the tomatoes are
generally warmer during the canning than they are after the cans
have been passed through the final process and allowed to cool.
Even then it is necessary at times to force the ends back to their

114 CANNING AND PRESERVING OF FOOD PRODUCTS.

natural position; this is called "snapping." It is generally thought
by packers that all cans are sound which give evidence of a vacuum,
and this idea has given rise to the belief that a vacuum actually
keeps the goods from spoiling. It is indeed surprising how gen-
erally this error has crept into the minds of packers and certain
manufacturers of vacuum machinery, too. Only two years ago a
certain manufacturer declared to me that he was able to reduce the
time of sterilization by twenty to twenty-five per cent. He claimed
to have the records to prove that his assertions were correct. An-
other manufacturer distributed broadcast a circular describing his
new vacuum machinery, by means of which he claimed to be able
to can fresh fruits and vegetables without heating (as far as I was
able to learn), and these he claimed would keep indefinitely with-
out fermenting or decomposing. This machine was manufactured
in Chicago, and its maker claimed that two canning houses were
running 40,000 cans daily by this method. I wrote to him and
warned him of the results which must surely follow, and told him
if I did not comprehend his system fully, I would be pleased to be
corrected. His reply contained the same claims, but I have never
heard of the two canneries who were putting out 40,000 cans daily
with his machine.

There are some machines on the market which have some merit
as vacuum machines, because they exhaust the air from the cans
while the contents are cold. This system is particularly attractive
for some goods, such as rrleats ; it accomplishes the same purpose as
the old venting method, amd the cold cans are more easily handled.
By the old method it was hecessary to heat the cans through to the
center, which required a prolonged venting process. Every canner
of meats remembers the time when the whole place was smeared
with the grease which squirted out from the awl holes necessary
in venting. The modern vacuum machine entirely does away with
all that extra labor, inconvenience and unsightliness. This vacuum
machine is made with a circular chamber, into which a dozen or
more cans are carried around a sprocket wheel. When the ma-
chine is filled the chamber is closed and the air is exhausted by
a vacuum pump. Each can has been previously capped, but the
vent hole is left open, and the air is exhausted from the cans through
the vent holes. Near the vent hole is placed a small button of solder
with the necessary flux, and as the cans revolve they pass under
a window and are tipped in vacuo by means of a tipping iron heated
by electricity. The iron is not automatic but is controlled by the
operator from the outside. A small electric light inside the chamber
furnishes the illumination. As each can is brought under the
window the small piece of solder is melted over the vent hole.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 115

When the cans are all tipped, the vacuum is released, and the cans
are carried out of the machine and carefully inspected for leaks.

As we have stated, the value of this device is the saving of
time and the neatness of the work. It does not decrease the time
required for sterilization, but does save the expense of venting.

The vacuum has no advantage as a means of shortening the
sterilization of any canned goods. To understand this thoroughly
let us study the character of the bacteria which are responsible for
the spoilage of canned goods. There are a great number of bac-
teria yeasts and molds which will cause chemical changes in can-
ned goods unless they are destroyed by sterilization.

Nearly all the bacteria which cause the spoilage of canned
goods after incomplete sterilization are spore-bearing organisms.
If there should happen to be a leak in the can, or should processing
be neglected, non-sporating varieties would set up decomposition.
Non-sporulating varieties are always destroyed at boiling tempera-
ture (212 F.) All spore-bearing bacteria which are responsible
for spoilage in canned goods are either anaerobic or facultative
anaerobic; that is to say; some are able to grow only when oxygen
is entirely absent, and some are able to adapt themselves to either
condition. The vacuum, then, is an ideal condition for the growth
of__anaerobic bacteria, because the stronger the vacuum, the better
the environment. The least trace of oxygen interferes greatly witli
the multiplication of these germs. When we speak of oxygen in
this connection, we mean free oxygen as it is found in the atmos-
phere. The anaerobic bacteria do require oxygen, but not in the
free state; their supply is always obtained from molecules of nutrient
substances which have oxygen chemically combined with other
atoms. In chemistry we speak of any substance as being made up
of molecules, and the molecules as being made up of atoms chem-
ically combined. A molecule is defined as a very small particle of
matter which has all the characteristics of the natural substance;
for instance, a molecule of sugar is the smallest particle which has
all the characteristics of sugar. A molecule cannot be farther di-
vided without destroying its character. Thus we may illustrate
C n H 12 O is a molecule of grape sugar which is fermented by the
lactic acid bacteria will be divided thus :

C H 12 O e 1 2 |C 3 H G 3
Grape Sugar] " (Lactic Acid

which would read thus : One molecule of grape sugar is divid-
ed into two molecules of Lactic Acid. A molecule is composed of
natural elements called atoms, and each atom is designated by a
letter, thus C 6 H 12 O means that a molecule of grape sugar is com-
posed of 6 atoms of Carbon, 12 atoms of Hydrogen and 6 atoms
of Oxygen, and when this combination is broken up other sub-

116

CANNING AND PRESERVING OF FOOD PRODUCTS.

stances are formed. As we have shown, the molecule of grape
sugar is changed by lactic fermentation into two molecules of
Lactic Acid. Now if we let grape sugar ferment under the in-
fluence of yeast or mold the following takes place :

C 6 H 12 ) f 2 C 2 H C j (2 C0 2

1 mol. grape sugar J 1 2 mols. alcohol j 1 2 mols. of carbon dioxid

Then again if we let grape sugar ferment under the influence
of the Acetic Acid bacteria we have the following:
C G H 12 | (3C 2 H 4 2

i mol. grape sugar J J3 mols. of acetic acid

These chemical equations illustrate the fact that a molecule is
entirely changed in character when it is divided. This gives a
splendid idea of chemical changes brought about by different organ-
isms, although in reality they are still more complicated, so that
instead of Alcohol, Lactic or Acetic Acid being formed alone, there
are usually several other complex substances formed at the same
time, such as glycerin, succinic acid arid volatile fatty acids.

Plate 28. Aspergillus Glaucus

Aspergillus Glaucus, showing the conidia on the tufts or sporangia. Magnified 350 diameters

Our readers will notice that in the fermentation of grape sugar,
the different atoms are torn apart, and the particular organism
responsible for the fermentation uses the elements for its propaga-

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 117

tion. Nothing is entirely lost chemically and although carbon,
hydrogen and oxygen are used to build up cell protoplasm, those
elements unite promptly to form the products elaborated by the
germs, and of course are characteristic of them.

The Anaerobic bacteria, therefore, obtain their supply of oxy-
gen from chemical combinations. This is true also of other bacteria
which are forced to grow in an anaerobic condition. The process
of decomposition is therefore more complete where the air is en-
tirely excluded from such micro-organisms, and the vacuum in
the cans is a favorable environment. The molds, yeasts or bacteria,
which consume large quantities of oxygen, must obtain that element,
consequently a much larger quantity of material must be changed
quickly for the supply of oxygen. In such cases the number of
germs present is quite small in comparison to the amount of ma-

Plate 29. Aspergillus Glaucus

Photomicrograph of the beautiful mold plant Aspergillus Glaucus. The fruit hyphae showing the bottle-
shaped sterigmae radiating from the columellae and the conidia are plainly visible. This is an unstained speci-
men mounted in glycerine and photographed. Magnified 500 diameters.

terial which is undergoing chemical change. Oxygen is more
difficult for bacteria to obtain when they are forced to grow in
a vacuum, because large quantities of material must be deprived of
oxygen. Decomposition is generally pretty well advanced when
spoilage is noticed in canned goods, because the vacuum of the can
has deprived the bacteria of free oxygen. Sterilization must there-
fore be complete, if goods are to be kept pure and imfermented in
tin cans or glass. The vacuum has absolutely nothing to do \\ith
the keeping quality of the goods, and we might add that the vacuum

118 CANNING AND PRESERVING OF FOOD PRODUCTS.

is a favorable condition for decomposition, unless sterilization is
complete.

Test tubes containing beef juice, corn juice, peas, etc., are
easily sterilized with only a cotton plug in the top ; there is no va-
cuum, but the germs from the air are filtered out by the cotton.
This is the method used in the laboratory for sterilizing culture
media.

Any canner may test the value of a vacuum for himself as
follows : Take a can of any perfectly sterilized goods, heat an awl
in a flame until it is red, heat a small surface of the can, holding
flame directly onto it; then punch a hole in the can without re-
moving flame, then seal the hole. The vacuum will suck air into
the can through the awl-hole but the air must pass through the
flame which destroys all molds and bacteria. Although the va-
cuum has been destroyed by the admission of heated air, the con-
tents of the can will remain in an unfermented condition.

CONCLUSIONS.

Molds, yeasts, anaerobic bacteria and bacteria which are facul-
tatively anaerobic, will grow in a vacuum, on a nutrient medium.
There is no such condition as an absolute vacuum in nature, but
there may be a condition where there is a partial vacuum, where
atmospheric oxygen is entirely absent or replaced by some other

1 gas. A vacuum will not prevent decomposition. Decomposition by
bacteria is more complete when air is entirely excluded from can-
ned goods. Sterilization cannot be accomplished in any less time
in the presence of a vacuum, since it requires a certain amount of

i heat, which must be applied for a given time, to destroy spores of

1 bacteria, yeasts and molds.

VALUE OF VACUUM MACHINERY.

Vacuum machinery may have some advantage over other meth-
ods of obtaining an exhaustion of air, viz., goods may be handled
cold and considerable labor of venting is saved. Jw reducing the
bulk of any goods such as milk where a high temperature is liable
to injure the flavor, a vacuum is valuable for removing the atmos-
pheric pressure, so that ebullition may take place at a comparatively
low temperature. Evaporation by this method has no value as a
sterilizing process where spore-bearing bacteria are present; it re-
quires the high temperature to destroy spores and the vacuum sys-
tem cannot give successful results in any less time than is actually
required where that condition is absent. Goods like milk, which
are condensed by boiling in vacuo, are not sterilized, but are pre-
served by sugar which must be added up to 50 per cent, in some

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 119

cases. Sugar is a preservative when used in large quantities, be-
cause it takes up the fluids. Bacteria require fluids for multiplica-
tion, so when sugar is used in excess the spores are deprived of
fluid, and therefore remain dormant, but are not destroyed.

Before closing, let me remark that no vacuum pump is able to
remove all bacteria from any goods. It may remove a large num-
ber from the small air space at the top of a package, but it can-
not exclude those forms which are in the goods themselves.

. * %

Plate 30. Saccharomyces Ellipsoideus

Photomicrograph of a wild yeast or wine ferment Saccharomyces-Ellipsoideus (Hansen) rounder oval cells,
which produce spores 2 to 4 microns in diameter, two or four being found in a single ascus. It forms a delicate
surface film in about two weeks at 75 degrees Fahrenheit. It produces a rapid and powerful fermentation, with
formation of great quantities of carbonic acid gas. Magnified 800 diameters.

The yeasts and molds are not the only species which produce
alcoholic fermentation; there are a number of bacteria which con-
vert glycerin media into alcohol ; the typhoid and pneumonia bacilli,
also a number of bacteria found in the mouth and on the teeth have
the same power. Some of the mucors are employed in pure cul-
tures in the manufacture of alcohol.

The yeasts cannot convert starch into alcohol, so in some places
molds are employed to convert the starch into sugar and the yeast
is then introduced to convert the sugar into alcohol. In the manu-
facture of malt beverages and vinegar the diastase is first employed
to convert the starch into sugar and this in turn is converted into
alcohol by yeast. Maltose and cane sugar are changed by a fer-
ment produced by yeasts, into glucose, which in turn is converted
into alcohol and the by-products. The chemical formulas are as
follows :

120 CANNING AND PRESERVING OF FOOD PRODUCTS.

C^H^A! + H 2 | |C C H 12 C + C H 12 C
Cane sugar + water J { Dextrose + Levulose

C 6 H 12 6 | | 2 C 2 H G + 2C0 2

Invert sugar J { Alcohol + Carbonic acid

The use of glucose in jellies, jams, catsup and other food
products is therefore fraught with danger. The atmosphere is laden
with wild yeasts which easily attack the glucose and fermentation
quickly follows. It has been customary among jelly and preserve
makers to adulterate the juices with glucose to give body and to
sweeten with saccharin, using some antispetic to retard fermenta-
tion. It is better to produce pure goods, although it may be ad-
visable in some cases to use a preservative, but the label should
plainly state the fact. Large quantities of glucose are mixed with
syrups and molasses to produce mild syrups, the object being to
produce a syrup of milder and more delicate flavor and not to
adulterate. These syrups are hard to keep and should be sealed
hermetically and sterilized and not preserved with antiseptics. The
manufacturers of syrups have a great deal of trouble along this
line.

ALCOHOLIC FERMENTATION is probably the most use-
ful chemical change accomplished by the lower vegetable orders.
By this process all alcoholic beverages and commercial alcohol are
manufactured. This fermentation is accomplished without the un-
pleasant odors and flavors so characteristic of many species of bac-
teria. The baking industry employs the yeasts and bacteria of
alcoholic fermentation to produce the carbonic acid gas for raising
or inflating what would otherwise be a heavy mass of dough.

In the preparation of sauces, catsups, syrups, jams, preserves,
jellies and food products of like nature the first fermentation is
generally alcoholic, due more commonly to the mold fungi but often
to wild yeasts so abundant in the atmosphere. The seed forms of
molds (called conida) give rise to this fermentation.

The conida are small round spores which abound on the tufts
of many varieties of mold and when they are submerged will bud
and multiply similar in many respects to the true yeasts or saccharo-
myces. Mold naturally grows on the surface of media which have a
slight acid reaction, and its oxygen requirement is very great. So
long as free oxygen of the atmosphere is to be obtained it grows
luxuriantly without causing any fermentation of the lower parts
of the material on which it is found, but if the oxygen is cut off
either by submerging or enclosing, it is forced to obtain its oxygen
requirement from the molecules in which oxygen is combined, and
new compounds are thus formed and a fermentation is set up which
in many respects resembles that of the yeasts.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

121

Plate 31. Mucor Mucedo

Photomicrograph of Mucor Mucedo in the living state mounted in glycerine. The round pod in the center
contains the seed forms or conidia. This pod is ripe, ready to burst when the conidia are carried by water or
air, ready to start a new mold plant or to set up fermentation according to the conditions in which they are
thrown. Magnified 800 diameters.

Plate 32. Mucor Mucedo, showing budding conidia

Photomicrograph of the budding conidia of Mucor Mucedo, obtained from a jar of spoiled tomatoes under-
going fermentation. These conidia have the power of setting up a fermentation similar in many respects to that
of the yeasts. In this manner of growth Mucor Mucedo looks very much like the brewers' yeast Sacharomoyces
Cerevisiae. Magnified 1,000 diameters.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 123

Various pulps are often filled into barrels hot, with a small
amount of antiseptic to prevent fermentation, but on cooling quite
a large air space is left above the surface of the pulp which is a
rich field for the growth of mold. After the formation of mold the
pulp will ferment if the barrel is rolled over and permitted to stand
for a short time in any temperature above 34 F. This accounts for
the large losses of manufacturers, who load and ship cars of bar-
reled pulp from one place to another during the spring of the
year. The pulp when stored away in cellars remains quiet for
months and appears good, but too frequently the mold is present,
and loss follows the moving. This may be overcome to some ex-
tent by boiling pulp down to 20 per cent, solids and refilling bar-
rels after cooling. Pulp stored in barrels will not keep unless
a small amount of preservative is added. The loss from alcoholic
fermentation may be minimized by canning the pulp in large tin
cans and processing. This insures a far better quality and does
away with the necessity of using antiseptics.

Plate 33. Acetic Acid Bacteria

Photomicrograph of the vinegar bacillus, Bacillus Acidi Aceti, which was isolated from a leaky can of
tomatoes. This is one of the organisms which are usually found in the "mother" of vinegar, which is called
Mycoderm Aceti. Solutions containing alcohol in amounts less than 15 per cent, are fermented and the alcohol
is converted into acetic acid. Stained with fuchsine and photographed through the microscope. Magnified
1,200 diameters.

ACETIC ACID FERMENTATION.

Acetic acid fermentation is one of the most important chem-
ical changes produced by bacteria. Vinegar is the chief commer-
ical product obtained, and while as yet pure cultures of bacteria

124 CANNING AND PRESERVING OF FOOD PRODUCTS.

are not extensively employed to produce it, there is a possibility
that present methods may be superseded and a vinegar of greater
strength obtained by the utilization of a single species known to
have the power to produce a higher per cent, of acetic acid than
when grown in company with other organisms.

There are a number of bacteria which produce acetic acid
when grown in liquids containing not more than 15 per cent, alcohol.
Pasteur demonstrated that acetic fermentation was due to the living-
organisms which formed slimy scum on the surface of alcoholic
fluids such as beer, cider, wine, etc. This scum was named "My-
coclerma aceti," which means "germ skin of acetic acid" or "mother
of vinegar." It is a zooglea mass of various bacteria, such as Bac-
terium aceti, B. Pasteurianus, Bacillus aceticus, Bacterium Kutz-
ingianum, etc.

Acetic fermentation is common and develops rapidly in the
alcoholic fluids when exposed to the atmosphere at a temperature
of 80 to 85 F., which is most favorable. Under favorable con-
ditions with pure cultures 14 per cent, acetic acid may be formed,
which is equal to 140 grain vinegar. The temperature given above
must be lowered after the acetic germs have performed their func-
tions to prevent oxidation of the acetic acid and water by the bac-
teria still living in the mycoderma. The chemical equations for
these two changes are symbolized as follows :

1 =C 2 H O + 2 = C 2 H 4 2 + H 2
Alcohol + oxygen = Acetic acid + water.

2 = C 2 H f O 2 + 20 2 + 2 CO 2 + 2 H 2 O
Acetic acid -f- Oxygen = Carbonic acid -f- water.

In the "mother of vinegar" the germs are united very closely
by mucinous envelopes, which are capsule-like formations, in which
the bacteria are imbedded. lodin stains these envelopes in a peculiar
manner. Those of B. Pasteurianus and B. Kutsingianum are stain-
ed blue, while the germs themselves are not. The envelope of B.
Aceti does not take the stain.

At the temperatures given, 80 to 85 F., involution forms oc-
cur.

By involution forms we mean that the bacteria change from
their natural forms, as shown in Fig. 30 and form threads which
are very much smaller in places and have no resemblance to the
normal shapes.

As mentioned before, vinegar is the chief commerical product
of these germs, and vinegar is formed from liquors containing not
more than 15 per cent, alcohol. Oxygen is absolutely necessary for
these organisms and they consume large quantities, and for this
reason the vinegar spirit is diluted with vinegar and allowed to run
slowly over beechwood shavings in a vinegar generator, thus ex-

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

125

posing the large surface to the atmosphere. These beechwood shav-
ings are sown with acetic acid bacteria and a rapid acidification
follows. By this exposure large quantities of alcohol are lost and
there are many forms of bacteria which find their way into the
spirit along with the acetic acid germs. Parasites such as Anguil-
lula aceti, the so-called vinegar eels, and Pythium anguillulae aceti,
make their appearance and consume both alcohol and acetic acid.
There are many people who have the opinion that these parasites
produce acetic acid, but such is not the case. The first named species
is the more common, but the second belongs to the fungi group of

u t Z <rjj i a. n u rn
X I ooo CHa7i tfe-n)

Fig. 30. Bacteria found in the Mycoderma Aceti

Oomycetes and these destroy the first species, as was discovered by
Sadebeck. The utilization of pure cultures of acetic acid bacteria
has not been accomplished outside the laboratory, but there is no
doubt that it is possible and practical. A vinegar of 14 per cent,
acetic acid strength may be manufactured with pure cultures from
the very spirit which is yielding only nine, ten and eleven per cent.
for the manufacturers under present conditions.

The additional yield of acetic acid means a great saving and is
worth the attention of manufacturers. Pure cultures may be ob-
tained easily by the plate culture methods, which were described in
Chapter III. The spirit can be sterilized and sown with the pure
culture and pure oxygen can be generated and forced into specially
prepared tanks in such a manner as to exclude all foreign bacteria
and parasites. Vinegar thus prepared will be of great strength
and promises large returns for the successful apparatus.

126 CANNING AND PRESERVING OF FOOD PRODUCTS.

The old method known as the Orleans method of manufactur-
ing vinegar is still used in many places. The method is thus de-
scribed by Lafar, page 397. "A number of oaken casks, each of a
capacity of some 55 gallons, are arranged in rows in a chamber
maintained at a constant temperature of 64 to 71 F. In the upper
part of the head of each cask a circular aperture is provided, through
which the cask is filled and emptied and which is generally kept
closed whilst near it is a very small vent always left open for the
admission of air. In normal work each cask is about half full. Be-
fore setting a new cask in work, it is scalded out several times v/ith
steam or hot water, in order to extract the sap from the wood, and
is_thetT^ 'soured' by impregnating it with good, boiling-hot vinegar.
About 22 gallons of good, clear vinegar on less than ^2 gallon of
wine are then placed in the cask, another V 2 gallon of wine being
added at the end of eight days, more after the lapse of another
week and so on until the cask contains 40 to 44 gallons." Vinegar
is then drawn from the cask after the "mycoderma" has formed
and this is replaced by the addition of wine. The cask is used for
several years when deposits are so heavy as to necessitate emptying
and cleaning-."

Plate 34. Acetic Acid Bacteria

Photomicrograph of Bacillus Acidi Aceti or Mycoderma Aceti or "Mother of Vinegar," showing short
dumb-bell rods, large lemon shaped and drumstick, involution forms. Produced acetic acid in tomatoes, isolated
by plate culture method; stained with fuchsine and mounted in xylol balsam. Magnified 1,000 diameters.

The slowness of this method is apparent and the opportunity
for contamination by injurious bacteria is great. There are enor-
mous losses of alcohol and acetic acid and the quality of the vin-
egar is often very poor. This process was improved (?) by Pasteur
in 1862, who cultivated the "mycoderma" or "vinegar flowers" in
small vessels and transferred this to the surface of the wine in vats
kept open and exposed to the air for the supply of oxygen, but

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 127

the process produces various results due to contaminations by harm-
ful bacteria. Pasteur's idea of cultivating the true acetic acid bac-
teria was good, but the apparatus is faulty. For this reason his
methods are not now in favor, the quick vinegar method having
taken its place to a very large extent.

These two processes have been outlined in this connection mere-
ly to point out the imperfections in them and not to describe the
best method of manufacturing vinegar. By the present methods
it is plain that the mixed germs employed in acetic fermentation
do not accomplish the best resits and that there is considerable loss
in alcohol and acetic acid.

In general, acetic fermentation causes very little trouble as a
source of spoilage in the food products industry. Wines used
in table sauces and soups may suffer from it if left exposed to-
the atmosphere and the same is true of any product in which alco-
hol is present not to exceed 15 per cent. Pulps which have under-
gone alcoholic fermentation either on account of wild yeasts or
molds will also undergo acetic fermentation along with other fer-
mentations such as lactic and butyric. Manufacturers of tomato
catsup who use barrel pulp can call to mind numerous instances
where the pulp had turned into vinegar and other complex acids.
The preservers have some difficulties, too; preserves, apple
butter, peach butter and light syrup goods are subject to slight al-
coholic fermentation, unless properly handled and sterilized, then
acetic fermentation follows with the loss of sugar.

Dill pickles, pearl onions are salted with just enough salt to
plasmolyze the harmful organisms, and alcohol is generated first,
then follows acetic and lactic fermentations to produce vinegar
having a characteristic flavor.

All vinegar having a certain per cent, of solids in liable to
deterioration through the agency of harmful bacteria, hence storage
in cool places is recommended for such as malt and cider vinegars.

BUTYRIC FERMENTATION.

There is a recipe for butyric fermentation given in some chem-
istries, as follows : Put into a 10 per cent, sugar solution a small
quantity of chalk and cheese and keep this at a temperature of 77
to 86 F. The first fermentation that starts is lactic in which lactic
acid and calcium lactate are produced ; the next is the butyric fer-
mentation which is set up by an anaerobic organism 2p broad and
from 2 I5/A long, which was discovered by Pasteur in 1861.
Pasteur did not class this germ as belonging to the bacteria but
considered it an animalcule, because it had a rapid movement. Its
manner of vegetating, however, is now settled and it can positively

128 CANNING AND PRESERVING OP FOOD PRODUCTS.

be said that it belongs to the fission fungi, because it multiplies by
lengthening and dividing and forms spores. It is endowed with
numerous flagella, growing out all over the surface of the cell and
by means of these its rapid motion is attained.

There are a number of bacteria capable of producing butyric
acid, some of which are anaerobic, while other are aerobic.

Prazmowski studied the cause of this fermentation and de-
scribes an organism which corresponds with the "vibrion butyrique"
discovered by Pasteur and named it Clostridium butyricum. An-
other germ similar in many respects was named Butyricus amylo-
bacter, which is so named because the cell contents resemble starch
which turns blue with iodin staining. So closely are the two germs
allied, however, that I believe them to belong to the same family.
In 1884 Hueppe discovered a bacillus which grows in the presence
of oxygen which he named Bacillus butyricus and another similar
to this was later discovered in old cheese and named Clostridium
foetidum, while from milk Bacillus liodermos has been obtained.

In butyric fermentation various compounds are produced such
as butyl alcohol, butyric, acetic and carbonic acids, hydrogen and
sulphuretted hydrogen, etc. The fats and carbohydrates are sub-
ject to this fermentation and a chemical equation may be thus
symbolized to show the decomposition of glucose into butyric acid,
carbonic acid and hydrogen.

C,H 12 6 ) JC 4 H 8 2 + 2C0 2 + 2H 2

Glucose, j ( Butyric acid -f- Carbonic acid + Hydrogen.

There are two kinds of butyric acid, differentiated in organic
chemistry as fermentation butyric and isomeric acid or isopropyl
formic acid, which is not obtained by fermentation; both have the
same chemical symbols but are differently arranged in atomical re-
lation. Butyric acid fermentation can be observed and studied by
our readers by boiling a small quantity of milk in a test tube and
allowing lactic fermentation to take place, which precipitates calcium
lactate, which is attacked by the butyric acid bacteria, and from this
cultures may be obtained by the plate method.

Butyric bacteria, whether they belong to the aerobic or the
anaerobic species form spores which are resistant to high temper-
atures. They are found on the leaves and fibre of nearly all kinds
of vegetables and cereals ready to set up butyric decomposition
whenever the conditions are favorable for their development. The
cellulose or fibre is the part usually decomposed by these organisms.
It is a remarkable fact that even paper, made from wood pulp, will
dissolve in a fluid undergoing butyric fermentation. It must not
be supposed that simple butyric acid is the only product elaborated
by species of this group since there have been isolated certain or-
ganisms which produce sweet-smelling ethers and aromatic sub-

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

129

Plate 35. Bacillus Butyricus Amylobacter, Flagellated

Photomicrograph of Bacillus Butyricus Amylobacter, an aerobic bacillus which when grown on substances
containing starch will stain blue with iodine. The flagella are very curly and were demonstrated by our special
method, from a 24 hours' growth on 2 per cent, glucose agar which had been inoculated from the juice of corn in
a swelled can. This organism is frequently found in decomposing vegetables and organic matter, and is not
found in the air. Its habitat is probably the soil. Magnified 1,200 diameters.

Plate 36. Bacillus Butyricus Amylobacter. Rods and Spores

This beautiful photomicrograph shows the free spores and the rods containing spores of Bacillus Butyricus
Amylobacter. The spores are generally formed in the center of the rods which cause them to swell in the middle
like spindles, hence they belong to the type called "clostridium." The spores are not easily destroyed by heat
and may live in corn which has received a temperature of 250 degrees for nearly one hour. Stained with car-
bol fuchsine. Magnified 1,500 diameters.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 131

stances which are valuable in the ripening of certain kinds of cheese,
Among these might be mentioned Butyricus Amylobacter which we
considered in the early part of this chapter, and Clostridum foeti-
dumelactis, which gives the flavor to Limburg cheese, also a sugar-
loving species found in soft country cheese called bacillus saccharo-
butyricus. Milk generally contains the spores of the butyric acid
group, and it is due to them that the disagreeable odors which are
associated with its decomposition are set free.

We make mention of cheese and milk and the bacteria asso-
ciated with them because they enter largely into the formulas of
special food products such as soups, macaroni and cheese (salad
dressings), etc., sold on the market under private names. There
are several different kinds of gases evolved where butyric fermen-
tation is going on, H 2 S (sulphuretted hydrogen), C O 2 (carbonic
acid gas), CH 4 (methane or marsh gas). There are, however,
some species which do not produce any gas. I isolated one species
from cream of tomato soup, which had coverted the milk sugar
and invert sugar directly into butyric acid without swelling* the
can. This species corresponded to the one isolated from soft cheese
by V. Von Klecki, which he named bacillus saccharobutyricus men-
tioned above. The soup had been given a process of 250 F. for
twenty-five minutes; the spoilage did not develop until a lapse of
three weeks. It was found by experiment that one hour at 250 F.
was necessary to destroy the spores of this organism. In some of
the cans the regular well-known species were found, but the cans
were swelled.

Butyric decomposition, while inimical to the canner's products,
nevertheless has its uses in nature, and in some industries. It plays
an important part in the preparation of brown hay, sweet ensilage
and sour fodder, and in the aging of manures. In the retting of
flax and hemp, the cellular substances are dissolved so that the fibre
can be obtained in the pure state.

Butyric decomposition is one of special interest to canners of
peas, string beans, asparagus, celery, corn and similar vegetables,
because the spores of different types of butyric bacilli are present
on surface of the pods and fibres. The butyric spores are usually
ellipsoidal in form and not quite so broad as the mother germ;
they withstand dessication remarkably well and high temperatures
are required to destroy them. There are some other kinds of spore
bearing germs which are more resistant than these, but not many;
250 F. for a few minutes will destroy the spores, but in order
to get this temperature at the center of the cans the nature of the
contents must be studied. If the material is heavy and thick and
contains much fibre, it will require a much longer time than when
the contents of the cans are strictly fluid. The exhausted cans are

132 CANNING AND PRESERVING OF FOOD PRODUCTS.

not absolutely without oxygen since the space within contains some
air, consequently strickly aerobic forms may be able to set up de-
composition. Usually, however, the decomposition is set up by an-
aerobes and facultative anaerobes. Since almost all butyric bac-
teria belong" to these two classes the conditions in canned vege-
tables are specially favorable for their vital activity.

The canning of such vegetables as are liable to butyric de-
composition should be clone very soon after they are harvested. The
growing plants are not favorable for the invasion of these bacteria
and it is only after they are harvested and attacked by other germs
such as the lactic acid group that the hardier forms begin their
work of destruction. They are specially active on vegetables which
are par-boiled and allowed to stand exposed and thus demonstrate
that they are true scavengers.

The development of spores and the formation of spores is ac-
complished in from thirty to forty-five minutes by the butyric bac-
teria when every condition is favorable. When partly cooked vege-
tables are allowed to stand too long the center of the mass will
be attacked by the anaerobic forms while the aerobic forms on the
surface are thriving. Those on the surface use up the oxygen
from the air, at the same time set free various gases and in this way
create the most favorable conditions for the development of the
anaerobic variety, the spores of which are scattered within the
mass. This is also true of the raw material which is piled too close-
ly. Here the peptonizing ferments begin to vegetate and soften the
fibre, causing the juices to ooze through their protecting sacs and
the temperature is increased so that the appearance of the vegetables
resembles par-boiling; in other words, they look as if they were
cooked. This is the condition as before described and butyric de-
composition progresses rapidly. A bitter flavor is often imparted
to such vegetables by a bacillus, which has given me considerable
trouble to isolate. It is a spore-bearing bacillus actively motile,
due to a large number of flagella. The spores are very hardy, re-
quiring about fifteen minutes at 250 F. to destroy them. They
are oval and located in the center of the rods which at times give
the bacillus a clostridium appearance. The development of the
spore is similar to that of the Bacillus megatherium of De Bary.
The young rod passes out of the spore at right angles to the long
axis of the spore and often retains the spore shell at one or both
sides. The bacillus is from 2^ to 6,tt long and about 0.81". to I/*
broad, with rounded ends similar to B. subtilis. It_forms butyric
acid and coagulates milk, is a facultative anaerobe and does not
cause the cans to swell. Cans of peas, asparagus and string beans
inoculated with a pure culture turn quite bitter within six days.
The colonies growing on agar are round with a pale, transparent,

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 133

very delicate zone surrounding them; the surface is white, slightly
wrinkled, becoming more so with age. When magnified by 2^0
they are yellowish and opaque. The deep colonies have a whet-
stone appearance. Grows well at a temperature of 85 to 90 F.

As bitter decomposition has caused the canners considerable
trouble at times the description here given will be interesting. The
bacillus may produce the bitterness in the "raw material if too long
exposed or to the partially cooked products if allowed to stand too
long before the final process, or it may develop in the cans if under-
processed. The spores are destroyed, however, at a temperature of
250 F. for fifteen to twenty minutes' actual heat; time required
for penetration of can and the contents must be added to this.

Frequently I have noticed that goods which have undergone
chemical changes due to bacteria have no living bacteria in the cans.
When the fluid is examined under the microscope there are numer-
ous bacteria present, but when agar or gelatin plates are inoculated
there would be no growth. These bacteria when mounted fail to
take the stains readily, which proves that they are dead. This
phenomenon will be noticed frequently by our students in their
researches and is explained in two ways ; either the bacteria were
destroyed during the sterilizing process, having previously accom-
plished the chemical changes, or they died under the influence of
the products elaborated by themselves, either before the sterilizing
process or more likely afterwards. If vital activity goes on after
the sterilizing process, the amount of acid produced is often germ-
icidal, and this may be accomplished in a few days : it is usually
after a longer time, however, varying from three weeks to six
months. The examination of spoiled cans should be made as soon
as possible after the trouble develops.

A great deal of the trouble experienced from butyric decom-
position is avoided by careful attention to cleanliness. Remember
that the floors and machinery will be covered more or less with
accumulations each day and this dirt contains the elements of what
you are packing. Failure to remove such accumulations by the lib-
eral use of soap and water, and at times a powerful disinfectant,
only invites an inimical host of bacteria, which is ready to attack
the fresh product which is being canned. The waste material
should be moved far away from the factory, and where practical it
may be put into silos and converted into money where a market
is offered for ensilage. The habit many packers have of loading
wheelbarrows and clumping cobs, husks, pea-pods, peelings and
waste just outside of the factory in great piles, is very dangerous.
While you may have been successful in one season with a certain
time and temperature in your sterilizing process, you may have
great difficulty during the next season. The atmosphere in the

134 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Megatherium, I>e Bary

Origin. Found originally on boiled cabbage leaves ; is present in the
air and in the soil; it is also found on other vegetable matter.

Form. Large cylindrical rods, having rounded ends, three to six
times as long as broad, and with granular contents. They are. found in
pairs, ordinarily slightly bent; they may form threads. Involution forms
are quite common, and capsulated cells are especially found in slimy
growths.

Motility. They have six to eight flagella, and have a slow, creeping
motion.

Sporulation. Median spores are formed.

Anilin Dyes. Stain readily, though irregularities may be seen which
are due to granular protoplasm.

Groivth. Rapid.

Gelatin Plates. Small, irregular, yellowish colonies are formed, which
later show marked branching or radiating forms these soon liquefy the
gelatin. Sometimes the colonies are kidney-shaped.

Stab Cultures. The growth is rapid, attended with liquefaction along
the line of inoculation, and may show threads of bacteria penetrating out-
ward into the solid gelatin. The gelatin becomes wholly liquefied later,
a flocculent mass accumulating on the bottom ; the liquid clears up without
any formation of scum on top.

Streak Cultures. On agar, a dull white or grayish covering is
formed. On potato, a thick, slimy, grayish-white mass is rapidly formed,
rich in spores and involution forms.

Oxygen Requirements. Aerobic.

Temperature. May grow in incubator, but optimum heat is at about
20 C.

Behavior to Gelatin. Liquefies rather slowly.

Patho gene sis. No effect has been observed.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

Plate 37. Bacillus Megatherium, Flagellated

Photomicrograph of an actively motile, spore-bearing bacillus which belongs to the Magatherium group.
It was isolated from some pickles to which it had imparted a most disagreeably acrid, bitter flavor. It requires an
acid medium for luxuriant growth, diluted malt and cider vinegar being particularly favorable. The numerous
delicate flagella were demonstrated by laboratory's special method, from an eight-hours' growth on acid agar.
Magnified 1,000 diameters.

Plate 38. Bacillus Megatherium, showing Spores

Photomicrograph of the spore or seed forms of the pickle bacillus shown in. Plate 37. The spores are
large, thick-walled, and are formed in the center or near one end of the rod and are rapidly self ree. Spore
formation takes place rapidly in 24 hours. From an agar growth, preparation stained faintly with carbol fuch-
sine and photographed through the microscope, using Spencer 1-12 oil immersion objective and acetylene radiant.
Magnified 1,000 diameters.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 1:57

neighborhood of your factory may be laden with the spores of new
varieties of hardy bacteria which have grown luxuriantly on the
piles of \vaste in the yard. These find entrance to your cans and
complications arise, goods undergo transformations, and you are
tempted to blame Providence for your losses. The canners who
are alive to the benefits of clean floors, machinery and tidy employes
and who remove every obnoxious element out of the factory and
yard are really the men who experience small losses from spoilage,
and their careful methods create a care for the quality of the goods
they pack and an interest in the selection of raw material. The re-
sult is that their goods bring the best prices, their establishments
are open to the public and the whole moral effect of cleanly meth-
ods is apparent.

LACTIC IvEvRMIvNfATlON.

Lactic fermentation is accomplished by a large number of
bacteria and is one of the most useful chemical changes. It is prob-
ably the earliest known form of decomposition, since milk gives a
good example, and milk has been used as food from the time of
creation and its use was no doubt familiar to the first inhabitants
of the earth. In the early days of the microscope forms of life
were noticed, chiefly those belonging to the wild yeast and mold
fungi; but not until the time of Pasteur was there any definite un-
derstanding as to the true cause of lactic fermentation, for all
theories previously advanced attributed the changes wrought in milk
to spontaneous generation. Lister was probably the first investi-
gator who obtained pure cultures of Bacterium lactis, a germ seldom
found outside of dairies. Hueppe followed with a more careful
investigation by means of gelatin plates and isolated several spe-
cies of bacteria which were capable of setting up lactic decom-
position. The principal organism discovered, by him was Bacillus
acidi lactici, which measures I to 1.7^ in length and 0.3 to 0.4^ in
breadth, non-motile rods, usually in pairs. Bodies resembling spores
are present, but they are not true spores, although so considered
by some authorities. Casein is precipitated and carbonic acid gas
is liberated at ordinary temperatures. Bacterium Prodigiosum, de-
scribed under head of Chromogenic Bacteria, Chapter II, produces
lactic acid.

Micrococcus acidi lactic (Krueger,) found as single or diplo-
cocci, is aerobic, forms lactic acid, and liquefies gelatin.

Bacterium lactic acidi, Bacillus lactis acidi, Bacterium acidi
lactis, Bacterium limbatum lactis acidi, Micrococcus lactis acidi and
Sphaerococcus lactis acidi, were isolated from sour milk by Marp-
man.

138 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Acidi Lactici, Hueppe

Origin. Found in sour milk, also in fermenting vegetable matter.

Form. Thick, short rods, two to three times as long as wide, usu-
ally found in pairs ; but rarely found in chains or threads.

Motility. It has no real motion, but has a marked Brownian move-
ment.

Sporulation. Round, terminal bodies have been observed, but are
not spores.

Anilin Dyes. Stain readily; so does Gram's method.

Growth. Rapid and abundant.

Gelatin Plates. The deep colonies are oval or round, yellow, finely
granular, with sharp borders. The surface colonies spread and form
thin plaques, having irregular wavy borders. The outer zone of the colony
is almost transparent at first, showing markings which resemble the veins
in leaves.

Stab Culture. The growth on the surface is considerable, spreading
rapidly ; it is a thin, dry, white covering ; growth along the puncture is
slight. In old cultures bundles of crystals are formed along the line of
inoculation, more especially at or near the surface.

Streak Culture. On agar, a grayish-white, moist, spreading growth is
formed. On potato, a brownish-yellow, slimy growth is formed.

Milk. In sterilized milk, the lactose is converted, in part, into lactic
and carbonic acids. Casein or curd is caused by the acid reaction thus
produced. The change will occur only in the presence of air. Old cul-
tures do not affect milk.

Oxygen Requirements. It is a facultative anaerobe.

Temperature. It will grow between 10 and 45 C., but grows best
at about 30 C.

Behavior to Gelatin. Does not liquefy.

Aerogenesis. It forms gas in milk; also forms carbon dioxide and
alcohol.

Pathogenesis. It has no effect. Growth is stopped by 0.75% lactic
acid. It produces lactic acid in the mouth (dental caries) ; also abnormal
fermentations in the stomach and intestines. Lactic acid bacteria promote
the growth of anaerobic bacteria.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 139

Bacillus lactis (Bleisch), found in buttermilk and frequently
in ordinary cream, is a large bacillus, forming spores of great re-
sisting power. It is a facultative anaerobic actively motile organ-
ism, and converts glucose into lactic acid without the evolution of
gas. The bacillus is about i> broad and 3 to 5^ in length and
may be cultivated in agar plates, or on a substratum of cream of
tomato soup. The specimen shown in Plates 40 and 41 was found
in a can of sour tomato soup in which no gas had formed, the
sugar having been broken up directly into lactic acid. On Agar
and potatoes it forms a light gray coating.

Plate 39. Lactic Acid Bacilli

Found on husks and in the juice of corn before processing. Causes souring of corn.
Magnified 1,200 diameters.

The chemical equation for fermentation by this organism may
be smbolized as follows ;

Grape sugar -[- water = Lactic acid (4 molecules).

C C H 12 = 2C 3 H C 0.,

Glucose Lactic acid (2 molecules).

The reactions are seldom so beautifully simple, however, for
there are liberated by various germs, gases of different kinds which
complicate the chemical equations, and the quantity of lactic acid
is of course less than the expression given here. Lactic fermenta-
tion, even where pure cultures are employed, is. accompanied by
acids of a volatile nature.

A number of Pathogenic bacteria have the power of producing
lactic acid when grown in milk; among these might be mentioned
the Cholera bacillus, Bacillus of typhoid fever, Bacterium coli corn-
munis, Bacterium lactis aerogenes and Friedlander's bacillus of
Pneumonia.

140 CANNING AND PRESERVING OF FOOD PRODUCTS.

LACTIC FERMENTATION is utilized commercially .. in
creameries to induce the souring of milk. For this purpose pure
cultures of the very best bacteria are obtained from the laboratories
and the cream is prepared and sown with these. Formerly the
souring of cream preparatory to making butter was left to spontane-
ous action of the germs present in the cream, consequently a poor
quality of butter was frequently turned out, clue to injurious bac-
teria which were present with the desired species. Pure cultures
of lactic germs are now made by and obtained from such stations
as the Chris Hansen Laboratory of Little Falls, N. Y., and the
acid generators are charged as follows : Skimmed milk to the
amount of two per cent, of cream to be soured, is Pasteurized by

Plate 40. Aromatic Lactic Acid Bacilli, Flagellated

Photomicrograph of an aromatic lactic acid bacillus found on putrefying tomatoes.
Magnified 1,000 diameters.

subjecting it to about 150 F., which kills many vegetating forms
of bacteria. The skimmed milk is then quickly chilled, thus weak-
ening the spores of the resistant species; then a pure culture of
lactic bacteria is sown in the milk, which is kept in a temperature
of 60 F. for twenty-four hours, in which time the lactic germs
begin to vegetate very fast and gain the upper hand of the species
previously weakened by heat. The acid generator is then ready
to be added to the cream, which has been Pasteurized in the same
way that was adopted for the skimmed milk. In another day the
cream will have turned sour and is ready for churning. Butter

DECOMPOSITION CAUSED BY HEtOffttMS. 141

made from cream thus treated is very fine in flavor, and is purer
and more wholesome than that made from cream which has soured
spontaneously.

Milk is a fine medium for the invasion of Pathogenic bacteria.
such as Tuberculosis, Typhoid and Diphtheria, etc., and all these
are destroyed in the Pasteurization should they happen to be pres-
ent..

A short description of modern butter-making in this connection
falls under this head, especially the consideration of bacteria there-
with associated. Butter is used extensively in various specialties
which are canned and served in buffet cars, so the peculiar flavor
of fine butter should be known to guide the canner in his selection.

I was kindly presented with a culture of bacteria used in the
best creameries for inducing lactic fermentation in Pasteurized

Plate 41. Aromatic Lactic Acid Bacilli

Showing rods and spores. Magnified 1,000 diameters.

cream by the Chris Hansen Laboratory, and here give a photomi-
crograph of the culture, which is named "Startoline." The culture
shows the presence of Saccharomyces Pastorianus, and a coccus-
described by W. S torch which measures about IP- in diameter.
There is also a fission fungus, discovered by H. W. Conn in 1895,
which is styled Bacillus No. 41. .This is a non-motile rod about
i.i/w. long, generally single, sometimes united in pairs, which grows
best at 75 F. Cream is not coagulated and very little acid is
formed by it.

The combined influence of these organisms is a pure lactic
fermentation set up by the cocci and the fine flavor produced by
the Conn Bacillus No. 41. There seems to be a difference between
the flavor and the acidification, which may be described as follows :

142 CANNING AND PRESERVING OF FOOD PRODUCTS.

The pure acidification gives a fine sweet taste to the butter, while
the flavor or aroma has the characteristic of what is known as
"grass flavor" or "June flavor," so marked in country butter made
when the grass is green and tender. The Conn bacillus was iso-
lated by him from a sample of milk he obtained from South
America, and it is employed by a large number of dairies through-
out the world.

Lactic acid bacteria play an important part in the preparation
of the yeast mash in distilling, vinegar-making, and brewing. The
preparation of the green malt for malt vinegar is interesting. The
malt has many kinds of bacteria associated, some belonging to
the butyric acid group. These are hardy types and these form
spores of great vitality. The malt is mixed with water and heated
to about 155 P., which kills all vegetating bacteria, but leaves

x-*

Jt
^ V &

/ ^

* ?1

Plate 42. Micro-organisms in Lactic Acid Generator, called " Startoline."

the spores of the undesirable germs uninjured, which, if allowed to
produce butyric acid, would prevent the yeast from accomplishing
its part. In order to prevent these from vegetating, artificial sour-
ing is induced by lactic acid bacteria, which acidity is antiseptic to
the butyric bacteria. The lactic acid fermentation is accomplished
either by the aid of pure cultures planted in the mash or by main-
taining the temperature at 120 P., which is about 20 higher
than the optimum temperature for the development of butyric bac-
teria. At 120 P., the lactic acid bacteria flourish well, and lactic
acid amounting to about I to i 1 /^ per cent, is formed, which is
ascertained by standardizing with normal alkali solutions, such as
sodium hyclroxid. The mash is then heated to about 155 P.,

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 143

which kills the lactic acid germs, also any other vegetated forms,
and after cooling sown with pure cultures of yeast, which set up
alcoholic fermentation without injury from the butyric and acetic
acid groups.

The advantage of using pure cultures of lactic acid bacteria
is great, for the reason that the spontaneous souring is apt to mis-
carry at times and forms of heat-loving bacteria often find their
way into the mash along with the lactic acid bacteria from the
air.

The pure culture now used is one discovered by Dr. Franz
Lafar, of Vienna, from a yeast mash in the Lietzen Distillerv.

Plate 43. Bacillus Acidificans Longissimus

Magnified 1,000 diameters.

He named the germ Bacillus aciditicans longissimus from the fact
that it is very much longer than the ordinary lactic acid bac-
terium. This organism measures i/* in breadth by from 2 to 2O/*
in length, and has the power of producing more lactic acid than
any other germ so far discovered. A pure culture \vas obtained
from the Berlin Experimental Distillery Station (Versuchsstation
fur Brennerei), Germany, but was dead when it reached us.

By means of pure cultures of this organism, lactic acid may
be produced at small cost compared to the price paid for the chem-
ical preparation. Lactic acid is required for special industries,
such as dyeing and color printing on fabrics.

Lactic fermentation takes place in the preparation of pickled
meats, sauerkraut, pickles, white pearl onions, beets, cauliflower,

144 CANNING AND PRESERVING OF FOOD PRODUCTS.

olives and various products which are put away for curing in 'brine.
Only a limited amount of salt is used at first because salt has anti-
septic power, causing plasmolysis of the germ cells. The lactic
acid group does not suffer in the presence of limited quantities, and
soon produces lactic acid in sufficient amounts to prevent the de-
velopment of the germs peculiar to the various food products which
are pickled.

The brine first added, ought to register about 75 on the Beaume
salt scale, and as fast as the salt is absorbed more salt must be
added until the fermentation is completed. At no time should
the scale show less than 50 degrees. The brine will be found
heavier at the bottom than at the top. so agitation is necessary
or a pump may be used to lift the bottom brine up to the surface.
If this be done once or twice a day good results will be obtained.

This method, while used extensively, is faulty from the fact
that the lactic fermentation is set up spontaneously by germs from
the atmosphere. The result is that harmful races of bacteria
sometimes gain an entrance in company with the lactic acid germs,
and unpleasant flavors are produced. Soft pickles, slimy rauli-
flower and discolored meats, are clue to the admission of bacteria
which break up cellulose and others belonging to the chromogenic
group described in Chapter II. The bacteria which gain entrance
with the lactic acid bacteria belong chiefly to the Subtilis group,
and these thrive well even in the presence of considerable quantities
of salt, and in the presence of lactic acid in limited amounts.

There is room for great improvement in the pickling of such
products as mentioned ; by first heating the raw material to a point
where all vegetating forms will be killed about 160 F. and
chilling, then by adding the proper amount of salt and sowing
a pure culture of lactic acid bacteria, uniform results can surely
be obtained.

PREPARATION OF SAUERKRAUT.

As we have stated, lactic fermentation plays an important part
in the preparation of sauerkraut, the lactic fermentation being in
fact the desired chemical change. Let us therefore look carefully
into the process and gather a few facts that may lead to improve-
ment of the quality and minimize the losses. After the cabbage is
cored and cut it is put into large wooden tanks with salt sprinkled
over each layer and packed firmly. Finally there is a top weighted
down, and according to present methods fermentation is permitted
to take place spontaneously. There are various spore-bearing bac-
teria and lactic acid germs throughout the whole tank. A gradual
increase of temperature takes place and the various spores begin

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 145

to vegetate in proportion to the amount of air that is circulating.
The temperature rises gradually until it reaches between 110 and
120- F.

At 100 F. the spore-bearing bacteria will gain the mastery
and as more weight is put on the top the air is excluded and the
temperature reaches about 120 F., which is the optimum point
for the lactic germs, and the activity of the other class is im-
peded. At this temperature the lactic fermentation goes on until
sufficient acid is formed to prevent decomposition by the other
class. Xow the improvement that suggests itself is this : Instead
of depending upon the lactic acid germs in the atmosphere to find
entrance to the cabbage, let a pure culture be sown throughout
the tank and the temperature raised at once to 120 F. Lactic
fermentation by the pure culture would begin at once, and the in-
imical germs would not be able to grow, which would give uni-
form results a beautiful white sauerkraut with a delicate aromatic
flavor. The temperature at the center may be tested by pushing
a self-registering thermometer down from the top. After having
once reached the proper temperature, pressure from the top can
be regulated to keep it uniform.

There is no branch of the food product industry which suffers
such severe losses as that devoted to brining and pickling, and there
is great need of improvement over present methods to enable the
manufacturers to depend on their processes. The installation of
the laboratory where pure cultures of useful bacteria may be ob-
tained is a great boon. There are many causes of spoilage in the
salting houses; frequently the water is bad, due to minerals and
injurious bacteria; different crops of raw material will vary in the
number and character of bacteria infesting them, and inability to
get proper fermentation at all times, makes the problem of se-
curing uniform results difficult. No fixed rule can be laid down
where dependence is placed upon spontaneous fermentation, and
the quality secured depends largely upon the kill of the one who
is doing the work. \Vith pure cultures, however, there is very
little chance to have poor quality if the material is good. There
is a marked improvement in the quality of goods turned out in
many industries due to the utilization of pure cultures of useful
bacteria, and the manufacturers of food products will also gradual-
ly become interested.

Xow let us condense the directions governing the lactic fer-
mentation in brining:

FIRST, make liquids containing pure culture of lactic acid '
bacteria by stirring the culture into a quantity of distilled water.

SJZCON-D., sprinkle the liquid over each layer of shredded
cabbage, also the required amount of salt.

146 CANNING AND PRESERVING OF FOOD PRODUCTS.

THIRD, increase the temperature to 120 F. and maintain
at that point until the lactic fermentation starts, then control the
temperature by pressure from the top.

ENSILAGE. We have referred to the utilization of waste
material, such as cobs, husks, peelings, strings and ends of beans,
pea pods, etc. The quality of an ensilage made from these depends
upon the care of the silo. The scientific principles are nearly the
same as those outlined for brining except that the salt is not used.
When the silo is filled, pressure is brought to bear to bring the
temperature up to 120 F., which is the proper point favorable
to the thermogenic bacteria, among which various races of lactic
bacteria predominate. There are other varieties, however, which
are heat-loving and some butyric and valeric acids are elaborated.
By this method the loss of digestible albuminoids is great and
compounds are formed which have no value in feed material for
cattle. Ammonia and amide compounds are formed by the decom-
position of albuminoids.

The undesirable features of this method can be entirely over-
come by controlling the bacteria which are useful in the production
of good ensilage. A pure culture of lactic acid bacteria, if sowed
in the silo at the proper time and at the temperature favorable to
their growth, will insure a valuable and marketable product for
feeding farm stock.

The lactic bacteria are utilized in the tanning industry in
'the fermentation of the plumping soak and the bark liquor, which,
of course, has no connection with the canning industry and simply
mentioned here as a fact, interesting from a bacteriological stand-
point.

Lactic bacteria, then, are useful in the preparation of various
food products and the transformations accomplished by them are
seldom inimical, as the great majority of them are easily destroyed
| at ordinary temperatures, but there is one, possibly two, varieties
which are associated with milk and form spores of great resisting
power.

PUTREFACTION.

Putrefaction is a term usually differentiated from fermenta-
tion by some authors because the material which undergoes putre-
factive decomposition is albuminous, while the carbohydrates are
changed by fermentation. Micro-decomposition, however, takes
in putrefaction, as such transformations, whether accomplished in
albuminous substances or in carbohydrates, are the result of the
vital activity of bacteria; in fact, the same germs are frequently
able to decompose either substance when planted under favorable
conditions.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 147

PUTREFACTION is accomplished in substances which con-
tain carbon, oxygen, hydrogen, nitrogen, sulphur, etc., while fer-
mentation has been restricted to substances containing only carbon,
oxygen and hydrogen. The breaking up of albuminous substances
is generally accompanied with disagreeable odors, which are no-
ticed in such elaborations as indol and skatol where nitrogen and
sulphur are combined. Sulphuretted hydrogen and the foul odor
of dejecta are due to the cleavage of protein matter. Ammonia
and the amines are the products of alkaline nature set free from
decomposing proteins, while acids often pleasant in taste and flavor
are formed by fermentation of carbohydrates. There are, however
a number of bacteria which are peculiar to putrefaction and are
seldom if ever found in carbohydrates.

The_learmg down processes are therefore complete, fermen-
tation splitting the carbohydrates and putrefaction splitting the pro-
teins into simple elements. In this manner all dead matter, whether
belonging to the vegetable or animal kingdoms, is reduced to simple
elementary compounds and is not permitted to accumulate. Bac-
teria frequently cause death to both plant and animal life, but death
may result from climatic changes or old age, or through renew-
ing processes. The leaves of the trees are touched by frost and
fall ; the blossoms perish and the animal sheds his skin and hair
and all nature is constantly putting off the old and renewing as
fast as necessary. Death therefore is natural and not always caused
by bacteria. One is apt to fall into the error that bacteria are
primarily the cause of all dead matter, since they are known to
be responsible for so many diseases, but close study of life will
teach us that this is not true. How wonderful then is the plan
of nature for the removal of the vast amount of organic matter
that is thrown clown all the time! Were it not for the bacteria
the earth would soon be unfit for habitation and nature would be
unable to furnish the elements necessary for removing worn-out
matter.

The carbon (in decomposing matter) (combined in the mole-
cules) is set free as carbonic acid gas, the hydrogen and oxygen
combine and form water, the nitrogen and sulphur in the protein
molecule form nitrates and sulphites and these elements are then
in a simple state and can be utilized by vegetable kingdom directly
and by the animal kingdom indirectly in building up new tissue;
the vegetable kingdom using the carbonic acid gas in the atmosphere
and the nitrates in the earth, and the animal kingdom using the
starch, fats, sugar, etc., obtained from the vegetable kingdom.
Thus we see that the vegetable kingdom is the source of nearly all
food supply, to the herbivorous animals directly and to the carnivor-
ous animals indirectly, while man is furnished by a vegetable diet
directly and a flesh diet indirectly by the vegetable kingdom.

148 CANNING AND PRESERVING OF FOOD PRODUCTS.

Vibrio Choleras Asiaticae, Koch (1884)

CHOLERA SPIRILLUM, COMMA BACILLUS; BACILLE VIRBULE (.FR.).

Origin. Found in the excreta of cholera patients, also in the in-
testines after death. Found several times in the water supply and milk.

Form. Short, rather thick rod, having rounded narrowed ends, and
varying from a straight rod to one bent in the form of a half circle ; it
usually resembles a comma, from which it derives its name of comma ba-
cillus. If two cells remain attached the letter "S" is formed. When
grown in liquid media under unfavorable conditions it may form long
spirals. The bent rod is a segment of a spirillum and is called a vibrio.
In old cultures peculiar involution forms develop.

Motility. Actively motile, usually having at one end a single flagel-
lum, sometimes two. Hanging-drop cultures should be developed at 37
motion, spirals and involutions occur.

Sporulaiion. So called Arthrospores. No resistant forms are known.
Not true spores.

Anilin Dyes. It is stained slowly. Carbolic fuchsin stains very well.
Does not stain by Gram's method.

Growth. At ordinary temperature it is fairly rapid.

Plates. On gelatin plates kept at 22, white or pale-yellow colonies,
coarsely granular, with irregular rough border which is surroundel by a
faint rosy hue, are formed. These colonies at first appear as small, white
points ; these gradually reach out to the surface, producing rather slow
liquefaction, so that funnel-shaped depressions are formed. The colonies
develop in fifteen to twenty hours. Entire liquefaction of gelatin occurs
after several days. On agar plates at 37, the large colonies present a
peculiar, bright, grayish-brown appearance which is quite distinct from
that of the common bacteria found in water and in feces.

Stab Culture. In gelatin growth occurs along the entire line of in-
oculation. A funnel-shaped liquefaction with an air space above form? at
the surface, the growth subsiding to the lower part. The lower part of
the puncture is gradually widened by liquefaction; the growth settles to
the bottom, and the entire contents of the tube are eventually liquefied.

Streak Culture. On agar, a glistening, whitish growth is formed.
It liquefies blood-serum slowly. On potato, kept in the incubator, a thin,
grayish or yellowish-brown, somewhat transparent layer is formed. This
resembles that of the glanders bacillus to some extent. Unless a mixed
culture is used no growth is obtained at ordinary temperature.

Bouillon. Rapid growth, especially in incubator, and a scum or pelli-
cle is formed on the surface. Cultures twelve to twenty-four hours old
display a reddish-violet color on the addition of sulphuric acid the indol
reaction due to the formation of indol and nitrous acid.

Milk. In sterile milk the growth is abundant, without much change ;
also in sterile water.

O.vvgen Requirements. Artificial cultures require oxygen.

Temperature. Grows best at 37 C. Will grow at i5-42 C. Killed
at 50 C.

Behavior to Gelatin. Liquefies slowly ; old cultures, especially.

Immunity. Subcutaneous or intra-peritoneal injections of the dead
or living vibrio yield a serum which is anti-infectious; injections of the
soluble toxin yield an antitoxic serum. The cell contents of the cholera
vibrios render immune. Pfeiffer's reaction with the serum of convalescents
or that of immunized animals or man (Chap. XIV).

Pathogenesis. Rabbits are killed very quickly by intravenous injec-
tions. In guinea-pigs intra-duodenal injections or introduction of cul-
tures into the stomach, previously alkalized, produce death with choleraic
effects. The intraperitoneal injection of agar culture is fatal in the ex-
treme to guinea-pigs ; is attended with rapid fall of temperature. Sub-
cutaneous injections of pigeons is not fatal. Typical cholera is pro-
duced in man by ingestion of cultures. The feeding of cultures to new-
born rabbits and guinea pigs is usually attended with fatal results.

Infection. Takes place along the alimentary canal, through water,
food, contact with freshly soiled matter, etc. The bacillus grows in the
intestines, and characteristic symptoms of intoxication are induced by the
soluble poisons elaborated by it.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

149

Putrid substances contain carbon and nitrogen in composi-
tion and the plants are unable to use them thus combined, so the
putrefactive bacteria set in to decompose these combinations and
the carbon is soon set free as carbonic acid gas, and the nitrates
and nitrites find their way into the soil as ammonia, and this is
utilized by plant life.

The putrefactive bacteria are called saprogenic, and by the
old writers the bacterium termo, which is not a name signifying
an individual species, but a class to which many allied species be-
long. The saprogenic bacteria may have the power to set up true
fermentation when planted in substances containing sugar, starch,
etc., but their true character is asserted in their ability to decom-
pose albuminoid substances.

Plate 44

The decomposition of albumen is generally attended with bad-
smelling gases. Some of these gases are so foul that the bacteria
which produce them are hard to handle. The odor elaborated by
one, called Proteus Vulgaris, is abominable.

The compounds which have such malodorous characteristics
belong to the aromatic class. Several of them have been isolated
by L. Brieger, M. Von Nencki, and E. Bauman.

Indol C S H 7 X is produced by quite a number of bacteria, and
its presence forms a basis of differentiation of closely allied species.

150 CANNING AND PRESERVING OF FOOD PRODUCTS.

It combines with nitrous acid as an imide to produce nitrose indol,
which is red in color. This characteristic is brought out by adding
Sulphuric Acid H 2 SO 4 in the test. The Cholera Spirillum was
the first pathogenic organism discovered which produced indol.

Skatol was isolated by Brieger in 1877 m human excreta, its
presence being attributed to bacteria in the intestines; it is a very
foul substance.

Sometimes, Phenol is a product of vital activity resulting
from the decomposition of albuminoid substances; also Orthocresol
and Paraocresol.

Methyl indol acetic acid is a very foul substance associated
with degradation, of albuminoids. It was isolated by N. Von
Nencki from a culture of Bacillus liquefaciens magnus, growing
in the anaerobic state.

Putrefaction is a common (phenomenon) in (imperfectly steri-
lized) canned goods of certain kinds, principally cans containing
meats, meat extracts, vegetables containing albumen, and milk.
This may be due to leaky cans or insufficient sterilization. The
odors from swelled cans of corn, peas, beans and all kinds of meat
are familiar to very canner of those products.

The greatest possible care in the packing of these goods is
essential. In the process of putrefaction there are various pto-
maines and toxic poisons formed, which sometimes cause consider-
able trouble. Whenever a case of poisoning occurs which the
physician attributes to canned goods, the packer suffers to some
extent, but the whole industry suffers more. Packers sometimes
get very poor advice from incompetent writers and the following is
a sample.

REPROCESSED TWEAKS.

The following quotations are made from an article which ap-
peared in one of the canners' journals in a series of articles pub-
lished for the benefit of packers :

"The first paragraph is headed 'Defective Cans,' and reads :
'While piling out, some defective cans may be detected; these
should have immediate attention. Open tip holes, repair cans, then
retip and reprocess regular time. In some instances these may
again be placed in the same grade of goods. When leaks are found
after goods have stood several days, open tip hole, repair can, ex-
haust, tip and process regular time. Goods thus treated may be
classed in a lower grade.' '

Such advice, scattered broadcast, is extremely dangerous.
There is probably nothing outside of deliberately putting poison
into food that would cause such dangerous stomach and intestinal
complications as this practice.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 151

In order that the packers may more fully understand the
danger of putting out reprocessed leaks, let us look into the subject
from various points of view.

1. There is danger of ptomaines forming in putrescible food.

2. There is danger of pathogenic molds and yeasts gaining
entrance to acid foods.

3. There is danger of tin and lead poison.

4. The quality is extremely poor, therefore detrimental to
the packers' reputation.

The first reason for not selling such goods is the danger of
ptomaines having formed in putrescible material.

There are a number of bacteria freely distributed in the air,
water and decomposing matter, which are capable of setting up
putrefactive processes. These bacteria will not, as a rule, grow
readily on raw material, but thrive luxuriantly on a great variety
of cooked foods. Owing to their wide distribution in nature, physi-
cians and some scientists have not taken true account of them and
their power to produce ptomaines. A ptomaine is a complex chem-
ical compound formed in several ways, principally as a product
elaborated by certain bacteria belonging to the putrefactive class,
and also to the pathogenic bacteria (which are the cause of diseases
in man and animals and are parasitic on living protoplasm).

Not all ptomaines are poisons ; only a few of them are so
classed, but these few are either formed or excreted by a large
number of bacteria. The poisons elaborated by the pathogenic bac-
teria are toxins which may be united with various other substances,
and these are termed ptomaines; the real poison, however, is a
toxin. Such bacteria as typhoid, tetanus, glanders, cholera, etc.,
all produce toxins, and these toxins unite with other compounds
which may be extracted with ether and thrown down as ptomaines.
The ptomaines commonly found in decomposing vegetables, meats,
fish, cheese, milk, etc., are generally due to the more common and
widely distributed organisms shown in the plates. There are also
other varieties generally regarded as quite harmless which form
ptomaines in very many different kinds of food, especially when
forced to grow in an anaerobic condition, that is, where air is ex-
cluded. In the ordinary tin can this condition is very nearly com-
plete, especially after fermentation has set in and carbonic acid gas
or phosphuretted hydrogen has driven out the oxygen through a
small leak. In such a condition the ptomaine bacteria are forced
to obtain that very necessary element oxygen from molecules
with which it is combined. The 'breaking down processes are there-
fore quite rapid and the chemical changes take place within very
limited time, so that canned goods could thus be changed within
forty-eight hours, or perhaps less.

152 CANNING AND PRESERVING OF FOOD PRODUCTS.

Ptomaine poisoning is much more common than generally
known. The evil effects are often experienced after meals, when
cramps are followed by diarrhoea and severe headache. Sometimes
these cases are quite severe, and the unfortunate suffer terrible
pains with tremors, followed by coma, and even death. The cases
on record are not a few, where whole companies of individuals
have been stricken after banquets, suppers, picnics, parties, etc.
Some of these cases have been thoroughly investigated, and the
ptomaine responsible has been obtained from cultures of the bacteria
found in the food. Usually in such cases the food does not, by
any peculiar taste or odor, indicate the presence of an injurious
substance. As we have previously stated, the chemical changes are
rapid and the potmaines may be formed where unperccived decom-
position is taking place. It usually happens that food containing
ptomaines has been exposed, or worked over, and the task of defin-
ing the cause of such poisoning is often quite difficult.

I could mention a number of cases from all parts of this coun-
try and Europe, where families have been stricken and the poison-
ing was charged directly against canned goods by the attending
physicians. In my writings on ptomaines, I have scored such de-
cisions by physicians mercilessly, because I firmly believe that many
of them jump at conclusions without proper investigation. Xow
permit me to say, if the packers should follow such advice a> ap-
pears in the quotation in the beginning of this paper, no one with
any respect for his integrity would dare to make defense against
the charge that ptomaine poisoning is due to canned goods. Any
physician who should happen to read that packers worked into
salable packages goods undergoing decomposition would, without
the least hesitation, cast the blame of such poisoning directly on
canned goods, if any had been eaten by the unfortunate persons.
In our laboratory work we have isolated from spoiled goods of
many different kinds, various bacteria classed as common, some
of them harmless to man when taken into the stomach, yet these
very bacteria will produce ptomaines and toxins, especially when
growing with other varieties. Even Bacillus Prodigiosus, the com-
mon bacterium which produces a red color on potatoes, bread, etc.,
a bacterium found commonly in the air, soil, water, decomposing
material, and on the leaves, pod^, vines and stalks of vegetation,
will produce metabolic compounds when growing with other or-
ganisms, and these compounds have known toxic properties, fatal
in some cases to animals, by subcutaneous and intraperitoneal in-
jections. Bacillus subtilis and bacillus allii. the former a very
widely distributed organism, the latter a bacterium found on de-
composing onions, give rise to poisonous compounds in some cases.
We have recently isolated a bacillus from a leaky can of mince

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

153

Plate 45. Ptomaine Bacillus from Mincemeat, showing Flagella

Photomicrograph of a bacillus found in perforated can of mince meat. This organism produces a
ptomaine. The growth is similar to proteus vulgaris. It is endowed with numerous flagella, which are the
organs of locomotion. It is actively motile. Isolated, stained by special method, mounted in xylol balsam, and
photographed through the microscope. Magnified with 1-12 homogenous oil immersion lens and illuminated with
acetylene radiant. Magnified 1,200 diameters.

Plate 46. Ptomaine Bacillus from Mincemeat

Showing rods and spores. Magnified 1,200 diameters.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 155

meat, which produces cholin, gadinin and trimethylarnin, well
known ptomaines. This mince meat was canned and a pie made
with it made one person very sick, causing cramps, cold extremities
and tremors.

i. Proteus Vulgaris, Mirabilis and Zenkeri and the colon bac-
illus are found throughout the alimentary tract in man and many
animals, also on cooked foods undergoing decomposition. They are,
therefore, quite common, but when permitted to grow in food will
produce powerful ptomaines.

How js itj_ then, that we are not more frequently poisoned,_if
these are,Q_CQiiimon? Of the varieties mentioned one or more are
taken into the stomach with various foods at every meal. We aim
to eat only fresh food, which passes into the stomach where it is
acted upon by the digestive enzymes, gastric juice, saliva and bile.
These substances retard the development of these bacteria and de-
stroy them in some cases. The food passes on to the intestines,
where the acids are neutralized and the food is rendered alkaline.
Here, then, is a favorable environment of temperature and alkalin-
ity, so great numbers of bacteria grow rapidly, only to be cast out
usually before any poisons are absorbed.

We can therefore readily see the difference between a partial-'
ly decomposed food (containing these bacteria and their poisons)
taken into the stomach, and perfectly fresh food, or food that has
been kept free from the action of bacteria.

From this it is quite reasonable to suppose that some of the
bacteria which form ptomaines will gain access to leaky cans and
will form these poisons rapidly. I want, to say here that after the
ptomaines are formed they are not always driven out by cooking,
in fact some of the most deadly ptomaines are active after cooking.
The bacteria may all be destroyed, but their poison remains.

2. There is danger of pathogenic molds and yeasts gaining
entrance to acid foods.

There are several molds that have been classed as pathogenic;
prominently, Aspergillus niger and Aspergillus fumigatus. Molds
grow well on acid fruits and vegetables and the products formed,
while not considered deadly, might cause stomach and intestinal
troubles. Several yeasts have been found which, when putrid, yield
metabolic compounds of a basic nature, belonging to the amine
group of ptomaines. (See Vaughn & Novy's "Cellular Toxins.")

3. There is danger of tin and lead poisoning.

It is a well known fact that tin and lead compounds are
poisonous. Ordinarily, in canned goods, these are present in such
small quantities that they are considered harmless. Several years
ago the Bureau of Chemistry, Department of Agriculture, at Wash-
ington, gave this subject considerable attention. Some of the tin

156 CANNING AND PRESERVING OF FOOD PRODUCTS.

Asperji'illus Niger, Van Tie<>-liem

Origin. In putrid substances, in the lungs of birds, and acid foods.

Color. Dark brown or black.

Mycelium. Low and at first white, afterwards brownish or black.

Fruit-Organs: The fruit hyphae are spherical, or flask or club-
shaped at the end which is covered with minute bottle-shaped bodies, ra-
dially arranged the intermediate spore-bearers or sterigmae from which
extend rows of spores. These sterigmae are divided. The spores are
brownish or black and spherical ; are 3-5 ^, in diameter.

Growth. Slow.

Bread Flasks. A low growth is formed which becomes very black.

Temperature. Grows best at about 35 C.

Pathogenesis. It gives rise to various ferments, diastatic, inverting,
and others. The intravenous injection of spores in rabbits is not followed
by as malignant results as with Aspergillus ftimigatus.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 157

plate examined at that time gave unfavorable results, but in gen-
eral there were found only small quantities of the oxids of tin and
lead.

"When decomposition sets in, however, there are formed acids'
which attack tin plate and the lead in the solder most vigorously,
and the gases throw them down in the form of insoluble oxids,
which are poisonous. Canned goods which become swelled be-
cause of leaks have formed considerable acid and gas by the ac-
tion of bacteria and when worked over must contain tin and lead
in appreciable amounts.

4. The quality is extremely poor,, therefore detrimental to
the packer's reputation.

Plate 47. Aspergillus Niger

Photomicrograph of unstained mold Aspergillus Niger, which is often seen on food products, which it
causes to ferment. It is pathogenic, producing substances deleterious to health. There are two large fruit pods
shown. These are full of ripe black spores as conidia. Just below is one of the black threads of the mycelium.
Magnified 600 diameters.

From all that we have written it must follow that goods sent
qut^with such compounds formed in them will be very poor in
quality: a second process would greatly injure the flavor in perfect-
ly pure goods, but when poisonous compounds are also present one
cannot imagine anything more detrimental both to the packer and
the consumer. The evil results do not end here; the whole canning ^
industry is assailed and maligned by the newspapers and hostile
writers, and the innocent are made to suffer witli the guilty.

Every can of goods you send out will probably reach a con-
sumer who is looking for something good to eat; every package
will either make a friend or an enemy for your brand, and when

158

CANNING AND PRESERVING OF FOOD PRODUCTS.

you are packing your goods think of this all the time. If you have
any cans which have suffered by accident in breakdowns of ma-
chinery or foreign matter having gained entrance, throw them
away rather than run any risk of sending out goods of inferior
quality.

Plate 48

What disposition can be made of leaks, you ask? Cut them
open, empty them and send the contents to the dump or wash
them away in the sewer. However wasteful this may seem do it
you will save more in reputation than you can ever gain by sell-
ing inferior and dangerous goods.

There should not be many leaks if there is a proper system of
inspection. I find that out of a pack of over ten million cans one
year I lost by leaks less than one-fifth of one per cent., or two out
of one thousand. It is a good plan to have two inspectors, and
women are, as a rule, quicker to see a leak than men. One of the
inspectors is placed at a point as near the automatic capper as
possible. As the cans pass this point all cap leaks, pin hole leaks,
etc., are taken off the conveyor and patched. The other inspector

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 159

is placed at a point beyond the tippers and all tip leaks, buttons and
cans with suspicious patching are sent back to the tippers.

The cans are conveyed into a tub of water where women
gather and pile them top up, into process crates ; and these women
are trained to look for leaks as they handle the cans. A small
premium for leaks found at this point is a good incentive for watch-
fulness and the cost can be made to fall on the inspectors and the
tippers, according to plans carefully made. One man to patch,
two tippers, two inspectors and four women to pile cans in crates
will be sufficient help to properly care for 50,000 cans daily, and
the leaks found in cans, imperfect tin and caps will not exceed, as
I have said, more than two out of one thousand.

I stated previously that leaks should be cut open and the con-
tents emptied. This should be done rather than to haul the swelled

Plate 49

Photograph of a can of tomatoes packed in 1884. This can is about the same diameter as a No. 2 can,
but taller. The tomatoes after twenty years are in fine condition, just as nice as freshly canned stock. No
"dating laws" required here.

cans to the dump. Strange as it may seem, in the large centers
we find poor people who will take swelled canned goods home and
eat them. In order to avoid any serious results it is better to dump
the contents. Of course some packers may say that the poor should
not do this, but in ignorance it is done, and the suggestion offered
is worthy of consideration.

160 CANNING AND PRESERVING OF FOOD PRODUCTS.

There are always a number of persons ready to take it up and
rush into prominence with such bills as "Canned Goods Dating
Bill" to correct the reported evils. There never was anything
more absurd than a dating bill for canned goods, but should a
ptomaine be present by any possible chance, a date on the can
would not warn the consumer.

AGE DOES NOT AFFECT CANNED GOODS.

From Gamier, March 2, 1905.

Plate 49 shows a can of tomatoes which was put up
in 1884. The tomatoes are as good as the day they were canned.
While the exterior of this can was very much rusted, the inside
coating was perfect and was no doubt a very superior grade of
tin plate. Age does not affect canned goods unless a perforation
should happen to be made in the tin. So long as the air is kept
away, the contents will remain in an unfermented condition.

From time to time there have been rumors of laws to de-
clare the date of the pack on tin cans in various states, the idea
being to limit the sale of canned goods to the year immediately
following the pack. This would be very unjust because, as we
say, canned goods are unaffected so long as the container prevents
the germs from the air from gaining entrance. We have opened
canned goods of various ages, ranging from five to twenty years,
and have found that in every case where the tin was not per-
forated, the contents were perfectly good and tasted as well as
the freshly canned product. American canned goods are the best
and most wholesome food in the world.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 161

CHAPTER V.

Decomposition Caused by Micro-organisms
(Continued)

Putrefaction, Bacteria of. Ptomaines and Toxins, Pathogenic
Bacteria and Their Action on Foods.

INTRODUCTION.

The study of putrefactive processes and the bacteria asso-
ciated therewith leads up to the products elaborated by these
groups. There are various products which are formed during the
growth and multiplication of these bacteria, but the most important
ones are ptomaines and toxins. These substances are not formed
in canned goods unless there are leaks or they are imperfectly steri-
lized, although it has been charged against them quite frequently. In
order to understand the nature of these substances and the bacteria
which produce them, I have thought it advisable to describe the
well known species.

The general character of contaminated raw material is care-
fully described, so that the manufacturer may be continually on
his guard. A fair understanding of the subject may reduce to a
minimum the chance of ptomaine poisons forming in manufactured
foods of all kinds. The study of this subject will be interesting
to the food chemist as well.

PUTREFACTION.

Sulphuretted hydrogen (H 2 S) is a foul gas usually present
during putrefactive processes. It has the sickening odor of rotten
eggs and is produced by a long list of bacteria. Albuminoid sub-
stances are rich in sulphur compounds and the sulphur is easily
liberated and combines with nascent hydrogen to form the gas.
Bacteria cannot form this gas where sulphur is not present, which
accounts for its absence where well known putrefactive bacteria
are cultivated in certain nutrient media. The putrefactive bacteria
use considerable sulphur in building up the protoplasm of their
cells and the gas is formed only in small quantities in some cases.

162

CANNING AND PRESERVING OF FOOD PRODUCTS.

Sulphur combines with ammonia and in some cases the__gas~is not
liberated in sufficient quantities to be easily detected. This is in-
teresting in connection with the production of jptpmaines, as it.
shows that unperceived decomposition may take place in albumi-
noid substances and poison may be produced by bacteria in suffi-
cient amounts to cause severe sickness, and even death, there being-
little or no evidence of any decomposition. The ordinary person
depends largely upon his sense of smell to determine the decom-
position of such foods as meat, fish, milk, cheese, etc., but it is
generally the case where there is no perceptible decomposition that
deceives because very few persons would eat any food that had a
suggestion of putrefaction. The custom in some countries of per-
mitting meats to age in order to soften the fiber must not be con-
founded with putrefaction.

Plate 50. Proteus Sulphurans

Photomicrograph of proteus sulphurans, a putrefactive organism which was isolated from decaying had-
dock. It forms great quantities of sulphuretted hydrogen. In all culture media the odor is abominable. It is
actively motile and bores into the deepest layers of decomposing flesh. It has a wonderful array of flagella.
Stained by our own special method and mounted in xylol balsam. Magnified 1,200 diameters.

Sulphuretted hydrogen is not easily perceived in the decom-
position of albuminoid substances where nitrates are present, as
these are reduced by the hydrogen to nitrites, both by aerobic and
anaerobic bacteria. The presence of this gas is easily demonstrated
in cultures of putrefactive bacteria by a simple and beautiful chem-
ical reaction. Gelatin plates are colored Madeira yellow with
(sodium ferri-tartrate 0.5 gram, water 50 c.c. and carbonate of
soda added until alkaline) ; this combines with the sulphur and
forms ferrous sulphate and a black halo or ring may be seen around

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 163

each colony of bacteria which produce sulphuretted hydrogen. It
may be stated here that peptone added to the gelatin insures a
more liberal production of the gas.

Nearly all pathogenic bacteria (bacteria which causes diseases
of man and animals), form this gas; the typhoid bacillus produces
sufficient quantities to be detected in a close room.

The bacillus which causes swine erysipelas produces more gas
than any other I have met; a bouillon culture resembles yeast fer-
mentation in the amount of gas bubbles liberated.

It must not be supposed that sulphuretted hydrogen is the
only gas associated with putrefaction ; there are various others ;
but its absence must not be taken as a guarantee that there is no
putrefaction.

Putrefactive processes occur in the intestines of man, .animals
and birds. In man the large intestine is where this phenomenon
takes place, and while putrefactive bacteria are not necessary, they
find their way to that location, being introduced with food and
water. The principal species is the Bacillus coli communis or
Colon Bacillus, which resemble the Bacillus typhi abdominalis to
such remarkable exactness that differentiation is difficult. The un-
digested albuminoids are attacked by this and other common putre-
factive bacteria and those foul products known as indol, skatol,
tyrosine, leucine, valeric acid, etc., are formed. . Various poisons
are formed also, but usually pass away without causing any danger-
ous complications.

There are a number of bacteria associated with putrefaction
which produce ptomaines and toxic poisons in ordinary articles of
food, such as meat, eggs, milk, ice cream, fish, cheese, etc., many
of which have been isolated and their poisonous products have been
separated. It must not be supposed that all putrefactive bacteria
produce these poisons. They all produce enzymes of various kinds;
some are poisons, while others are quite harmless. There are some
ptomaines also which are not poisons, and to speak of all ptomaines
as such, is a mistake which has only recently been cleared up. Put-
rescine and Cadaver ine are two which were formerly considered as
poisons, but recent investigation has proved the opposite.

Some of the pathogenic bacteria produce-ptomaines which act as
powerful poisons ; many of the toxins have been separated and in-
vestigators are working to obtain these principles from all disease-
producing bacteria. Some diseases formerly thought to be incurable
have been successfully treated \vith the specific toxins of the bac-
teria which cause them. Among these might be mentioned, the
anti-toxin obtained from cultures of Diphtheria Bacilli, which effects,
wonderful cures of diphtheria, and recently the tetano-toxin ob-
tained from cultures of Tetanus Bacilli has effected cures of lock-

164 CANNING AND PRESERVING OF FOOD PRODUCTS.

jaw when all hope of recovery by other means had been given up.
These toxins, however, are not used in the pure state, which would
prove fatal, but are attenuated by inoculating animals from which
the weakened toxin is obtained in the serum. ,

Pathogenic bacteria will produce poisons on nutrient substances
which, have no albumen in their composition; these poisons are
formed synthetically. These poisons have been named active al-
buminoids by the investigators who made the discovery. They re-
semble enzymes and have the power to decompose certain sub-
stances characteristically just the same as the ferment deposited
by the yeasts. These active albumens are destroyed by 212 F.
and become passive.

This discovery is valuable to the manufacturer of food pro-
ducts, since it throws a flood of light on many cases of poisoning
blamed on canned goods. Many people eat uncooked meat in the
so-called "cannibal sandwiches," smoked sturgeon and halibut, and
m the same meal eat canned goods. If poisoning results, too often
the blame is fastened on them, which causes considerable criticism
of canned goods. Pathogenic organisms find their way into milk
and on some raw vegetables, clue to sprinkling with contaminated
water, and the active albumen formed often causes severe cramps
and even death. Cholera infantum is probably the result of con-
taminated milk; indeed, the common potato bacillus, Mesentericus
Vulgatus, is capable of causing severe intestinal complications where
milk containing it is given to infants in nursing.

There have been cases of ptomaine poisoning, however, which
could possibly be traced to canned goods. There have been and
possibly are today packers of canned goods who either are ignorant
of the danger of canning unsound products or else they are un-
scrupulous. Such men cause a great, deal of trouble to the industry
as a whole, for all must suffer the severe criticisms of the press and
must battle against unjust legislation. A National Canner's As-
sociation could put a stop to such practices.

I know personally one packer of meats and sausages who was
arrested a number of times for attempting' to use contaminated
material. "No one would known the difference after ij; is canned,"
was his expression. There is no telling how much trouble this
man may have caused, and it would hardly be supposed that there
were no cases of poisoning where his goods were marketed. HP
used fictitious labels and covered his name so that it would be
difficult to trace any complaints.

Such men should be forced to either put up wholesome goods
under their own names or be compelled to get out of the business,
and to accomplish this the law demanding the name of the manu-
facturer to be printed on his labels is wise and beneficial. There

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 165

would be no advantage in dating such goods, for unsound goods
could not be detected by a date on Ihe can.

There should be great care exercised in the selection of all
raw material, especially such as contains albumen and is liable to
putrefaction. There are means of knowing when raw material is
good, both from general appearance and microscopical examination.
Every canner should possess a good microscope, with an improved
oil immersion lens.

There are a number of bacteria associated with meat poisoning
which we will now describe, and these may be studied carefully,
as the plates and descriptions will serve as a guide and reference.

One of the most common germs which produces a ptomaine is
Proteus Fulgdris, found in putrefying meat. The rods are gener-
ally found in pairs. They measure 0.9 i.2,u in length, 0.4 o.6/*
in breadth, but occasionally forms are seen 6/t long and they fre-
quently form threads (100 /* long) when cultivated in nutrient ge-
latin. Spirilla, or curved threads, spirulina, or twisted threads,
are also seen in gelatin cultures. Involution forms with swelled
ends resembling dumb-bells and lemons are met with. The colonies
on gelatin show the twisted and straight threads growing out from
the center and these sometimes move out into the gelatin, becom-
ing detached, so that the name of " Swarming Islands" had been
given to them. The detached colonies sometimes resemble curious
designs and figures and the name of "Bacillus figurans" has been
given the germ on account of this peculiarity.

It is arhactively motile organism on account of the large num-
ber of flagella it possesses which radiate from the whole surface
of the cell

The motion is seen to be in two directions; it turns on its
long axis and moves rapidly forward at the same time. There is
no spore formation and the cell life is easily destroyed by a moist
temperature of 150 F. ; in fact 135 F. kills it in a few minutes.
It is a facultative anaerobe and grows well at 70 to 98 F., best
at 75 to 80 F. It is stained well with carbol fuchsin, but Gram's
method is negative.

On Gelatin Plates it forms small, round, yellowish colonies
with thick centers, with the peculiarities before mentioned. The
Gelatin is rapidly liquefied, both in plate and stab cultures.

On Agar a moist gray layer is formed, spreading rapidly over
the entire surface.

On Potato a grayish coating forms.

Bouillon is uniformly clouded. Milk is coagulated and made
faintly acid. It produces large quantities of sulphuretted hydrogen
and forms inclol; grows well in the presence of hydrogen and
carbonic acid, and the odor from all media is abominable.

166 CANNING AND PRESERVING OF FOOD PRODUCTS.

Proteus Vulgaris, Hauser

Origin. It is very widely distributed; is commonly present in the
putrefaction of animal proteins ; has also been found in water, in mecon-
ium, in purulent abscesses, and in the blood and tissues of several cases
of fatal putrid infection of the intestines.

Form. Rods varying in length from short oval forms to those which
are two to six times as long as wide. Grows in pairs, is usually bent ;
sometimes forms twisted, interwoven threads. Roundish involution forms
are commonly found.

Motility. Actively motile, with from sixty to one hundred flagella,
arranged all over the surface.

Sporulation. Not observed. Cultures are resistant to dessication and
retain vitalit.y for many months.

Anilin Dyes. Stain readily. Will not stain by Gram's'method.

Growth. Very rapid.

Gelatin Plates. Gelatin is rapidly and extensively liquefied. The
colonies are of a yellowish-brown color, having bristly borders ; in soft
gelatin they have a tendency to spread over the surface, forming peculiar
figures. Detached portions of the colonies may be observed to move
about, which has gained for them the name of "swarming islands." A
disagreeable odor is noticeable. They have an alkaline reaction.

Stab Culture. Liquefaction extends along the entire line of inocula-
tion; it is very rapid, and the whole contents are liquefied in a few days.
The liquid, which is at first diffusely cloudy, clears up later and a flocculent
sediment settles on the bottom. At the same time a grayish-white layer
is formed on the top.

Streak Culture. On agar, a grayish, slimy, rapidly spreading growth
is formed. On potato, it forms a dirty colored, sticky covering.

Oxygen Requirements It is a faculative anaerobe.

Temperature. The optimum is between 20 and 24 C. ; it grows very
well in the incubator.

Behavior to Gelatin. Liquefies rapidly.

Aerogenesis. Hydrogen sulphide is formed.

Pathogenesis. It has no effect in small doses. Toxic effects and
even death, are produced by the injection of large quantities of living or
filtered in rabbits and guinea-pigs. It is toxicogenic and sometimes may
be pathogenic.

This and several related are included in the Bacterium termo of the
older writers.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

167

Plate 51. Proteus Vulgaris, Flagellated

Photomicrograph showing proteus vulgaris which produces a ptomaine. Magnified 1,500 diameters.

Plate 52. Proteus Vulgaris, showing " Swarming Islands."

Contact staining by the author. Magnified 75 diameters.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 169

Pathogenesis. Animals, when subject to intravenous injec-
tions of Proteus cultures, die of acute enteritis and peritonitis, pre-
viously exhibiting typical symptoms of poisoning, such as bloody
vomiting and diarrhoea, combined with severe tremors and feverish
temperature.

The toxin is no doubt of a poisonous nature and is not de-
stroyed by heat, even after the bacilli have perished. Patients
suffering from "Weil's disease" are afflicted with this parasite,
which may be obtained from the pus and urine.

PROTEUS MIRABILIS.

Proteus Mirabilis greatly resembles the organism just describ-
ed, yet has distinct characteristics. The rods are various lengths,
closely resembling vulgaris, but the threads are much longer, often
attaining a length of 200^. They are- motile and possess many!
flagella. Spore formation is absent. The Gelatin plates and stab'
cultures are slowly liquefied. The deep colonies from curiously
twisted masses or zooglea.

Large quantities of sulphuretted hydrogen are formed. Cul-
tures show a decided indol reaction ; milk is coagulated with faint
acid reaction. Bacilli grow fairly well in an anaerobic state, either
in hydrogen or carbonic acid gas. They are found in putrefactive
processes and produce a toxin similar in its pathogenic effects to
that elaborated by Proteus Vulgaris. The odor produced when
cultivated on all nutrient media is very foul.

PROTEUS ZENKERI.

Proteus Zenkeri, called by some authors Bacterium Zopfii, is
a bacillus 0.4^ broad and about i.$n long, resembling the two pre-
ceding species, but it is smaller and does not liquefy gelatin. It
occasionally forms "Swarming Islands", like the other two and the
other biological characteristics are similar. It is a peritrichous
(many flagella) organism and produces a specific poison.

These three germs belonging to the Proteus family are re-
markable for their rapid boring movements. They swarm through
media which are solid enough to confine most motile bacteria. Our
readers will bl able from these descriptions and plates to recognize
any of them under the microscope either in plates or in stained
preparations. Other bacteria associated with Ptomaine and Toxic
poisons.

BACILLUS BOTULINUS.

This putrefactive organism was discovered by Van Ermengem
during an epidemic of poisoning from meats at Ellezelles in Bel-

170 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Mirabilis

Origin. It is very widely distributed ; is commonly present in the
putrefaction of animal proteins ; has also been found in water, in mecon-
ium, in purulent abscesses, and in the blood and tissues of several cases
of fatal putrid infection of the intestines.

Form. Rods varying in length from short oval forms to those which
are two to six times as long as wide. Grows in pairs, is usually bent ;
sometimes forms twisted, interwoven threads, longer than Vulgaris.
Roundish involution forms are commonly found.

Motilily. Actively motile, with from sixty to one hundred flagella,
arranged all over the surface.

Spontlation. Not observed. Cultures are resistant to dessication and
retain vitality for many months.

Anilin Dyes. Stain readily. Will not stain by Gram's method.

Growth. Very rapid.

Gelatin Plates. Gelatin is slowly liquefied. The colonies are of a
yellowish-brown color, having bristly borders ; in soft gelatine they have
a tendency to spread over the surface, forming peculiar figures. De-
tached portions of the colonies may be observed to move about, which
has gained for them the name of "swarming islands." A disagreeable
odor is noticeable. They have an alkaline reaction.

Stab Culture. Liquefaction extends slowly along the entire line of
inoculation.

Streak Culture. On agar, a grayish, slurry, rapidly spreading growth
is formed. On potato, it forms a dirty colored, sticky covering.

Oxygen Requirements. It is a facultative anaerobe.

Temperature. The optimum is between 20 and 24 C. ; it grows very
well in the incubator.

Behavior to Gelatin. Liquefies rapidly.

Aerogcnesis. Hydrogen sulphid is formed.

Patho genesis. It has no effect in small doses. Toxic effects and even
death are produced by the injection of large quantities of living or filtered
in rabbits and guinea-pigs. It is toxicogenic, and sometimes may be
pathogenic.

This and several related are included in the Bacterium termo of the
older writers.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

171

Plate 53. Proteus Mirabilis, Flagellated

Photomicrograph of proteus mirabilis, an organism which produces a ptomaine. Isolated from putrefying
meat. Magnified 1,200 diameters.

Plate 54. Proteus Mirabilis, showing " Swarming Islands."

Contact staining by the author. Magnified 75 diameters.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 173

gium. The peculiar symptoms exhibited by the unfortunate vic-
tims of the botulinus group of bacteria, are nervousness of central]
origin, disturbances in the muscular system, the salivary and other
secretions are suspended; difficulty in swallowing; hoarseness, my- 1
driasis and ptosis, and death sometimes follows. The_origin of \
'1>otuhsmllJaas_been traced to contaminated salt fish, smoked meat,
such as ham, preserved meats, blood and liver sausages, etc.

Bacilli botulini are seen under the microscope as large motile
rods measuring 4 to 6/^ long and 0.9 to 1.2^ in thickness, having
rounded ends. Various involution (odd shaped) forms are some-
times seen. Threads are rarely formed, though sometimes three
to ten rods will remain united.

When properly stained four to eight flagella can be counted,
which give the bacillus a creeping motion. It stains readily with
nearly all colors, and also by Gram's method (see article on stain-
ing) where alcohol is not used to excess.

It forms spores which are ellipsoidal and are situated in the
ends of the rods (terminal spores). They are rarely median.

The vegetating forms are killed in boiling temperature 212
P., but the spores are more resistant. 250 F. kills them in a
very few minutes.

Bacillus botulinus is anaerobic and grows well at 75 to 85
F^but will grow without sporulation at 98 F. Involution forms
appear at blood temperature. The best artificial media for culti-
vation are made slightly alkaline with an addition of 2 per cent,
grape sugar. It produces butyric acid and a toxic poison which
can be precipitated in almost pure state by treating a bouillon cul-
ture with absolute alcohol, neutral salts and tannic acid.

Gelatin plate culture ; round, transparent, brownish yellow
colonies make their appearance in four or five days. These colonies
have a thick, lustrous, granulated appearance, slightly liquefying
the surrounding gelatin. When magnified sixty times the margins
appear slightly irregular and radiating. In the stab cultures the
course of the needle shows a white growth extending into the sur-
rounding gelatin, which is liquefied with the evolution of consider-
able gas.

Grape Sugar Bouillon is clouded very much ; in milk there is
no coagulation and it remains unaltered.

Pathogenesis Guinea pigs, cats, mice and dogs are killed by
inoculation with the poison and also with the pure cultures. The
nerve centers are greatly affected, principally the medulla oblongata,
the ganglion of the hypolossal nerve, the dorsal ganglion of the
vagus, the small-celled ganglion of the motores oculorum and
brain nerves.

174 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Zenkeri

Origin. Found in intestines of chickens ; also in feces, water and
putrefying substances.

Form. Rods, two to five times as long as wide. Threads are formed;
in gelatin they are often bent or twisted in peculiar shapes, resembling
spirals. Coccus-like involution forms abound in old cultures.

Motility. Actively motile.

Spomlation Involution forms are found which resemble spores.
These are said to resist dessication, but are easily destroyed by heat, and
stain readily with anilin dyes.

Anilin Dyes. Stain readily.

Growth. Rapid.

Gelatin Plates. Delicate, cloudy patches of radiating threads are
formed by the colonies, which show, under the microscope, in addition to
these, numerous small, rounded bunches of cells.

Stab Culture. There is a marked growth in the upper part of the
tube, but none in the lower part; fine radiating lines penetrate into the
gelatin, most deeply at or near the surface.

Streak Culture. On agar, a very thin, dry, grayish growth is formed.

Oxygen Requirements. It is an obligative anaerobe.

Temperature. Grows best at ordinary temperature. Will grow at 37
to 40 C. but has a tendency to develop involution forms and to die out.

Behavior to Gelatin. Does not liquefy. No indol.

Pathogenesis. Produces a ptomaine.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 175

Bacillus botulinus is sometimes found in putrefying meat, gen-
erally in the lean parts, seldom in the fat, and is able to flourish
when the surface is covered with the aerobic putrefactive bacteria,
which use up the oxygen and make the conditions favorable within
the tissue for the development of anaerobic species.

This bacillus is particularly dangerous from the fact that it
forms spores which will live through pickling and smoking pro-
cesses and will afterward develop. Van Ermengem discovered the
bacillus in a ham which had poisoned a number of people.

Albuminous foods, if properly handled in the raw state, will
not suffer from this organism. Exposure to putrefaction is dan-
gerous..

Plate 55. Proteus Zenkeri, Flagellated

Photomicrograph of Proteus Zenkeri, an organism which produces a ptomaine. Isolated from putrefying
meat in a leaky can. Magnified 1,200 diameters.

BACILLUS ENTERITIDIS.

Bacillus enteritidis belongs to the Coli group. It was discov-
ered in 1888 by Gartner in a meat poisoning epidemic. He ob-
tained it from the tissue of a cow, which died of mucous diarrhoea,
and from the spleen of a man who had died from eating its
flesh. It is morphologically identical with the Bacterium Coli Dys-
entericum, which has been proved to be the cause of epidemics of
dysentery;

Bacillus enteritidis has been found to be the cause of many
cases of poisoning from meats; it appears as rods 2. to 4^ long and
0.4 to O.6/J. broad. The ends are rounded and are refractive,
especially when the organism is cultivated on gelatin and examined
in the hanging drop culture. It possesses five to ten flagella and

176 CANNING AND PRESERVING OF FOOD PRODUCTS.

Plate 56. Bacillus Botulinus, showing Flagella

An organism which produces a poisonous ptomaine.

-jfn-

' &* u

* ^/J^^/^5 1 ^'.

r L^SS^"^
^wSMSSrif 1

-a^^SS^nV*
% ^C^ % ^V s

^% % * ^ J^

> i - -S*

* I nif

^ t

Plate 57. Bacillus Botulinus, showing Rods and Spores

Magnified 1,200 diameters.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 177

is motile. (This is denied by Lehman and Neumann.) Their error
is possibly due to investigating old cultures. Cultures twenty-four
hours old show a true independent motion and flagella can be de-
monstrated by the method of staining (described in Chapter III).
The rods stain more deeply in the middle than in the ends, due to
their richness in fat of alkaline nature. An even stain may be
made by first treating the germs with a 20 per cent, solution of
Sulphuric, .Acid, H 2 SO 4 , which neutralizes the alkaline, and the
stain takes quite readily afterwards. Gram's method is negative.

It grows well in temperatures ranging from 70 to 100 F.,
best at 98 F. Gelatin Plates show the superficial colonies as thin,
almost transparent films, and there is no liquefaction of the gelatin,
either in plates or Stab Culture. There is very little odor in any
of the culture media.

Plate 58. Bacillus Enteritidis

Photomicrograph of an organism which produces a deadly poison. Magnified 1,000 diameters.

AGAR PLATE cultures show a gray film, almost transparent.
Bouillon cultures is uniformly clouded. Grape sugar bouillon is
acidified with the evolution of Carbonic Acid Gas and a combusti-
ble gas similar to marsh gas. Milk Sugar Bouillon is not acidified,
but the same gases are formed less abundantly.

MILK is not coagulated nor changed chemically. Young cul-
tures do not form indol; old cultures show slight traces. It is an
aerobic organism, facultative anaerobic in the presence of grape
sugar.

178 CANNING AND PRESERVING OF FOOD PRODUCTS.

PATHOGEN ESIS. When this organism grows on meat a
powerful ptomaine poison is found which heat does not destroy.
Even the broth from such meat will contain the poison. The poison
may be precipitated with absolute alcohol, tannic acid and neutral
salts, if acid is present.

Live cultures of the germs when inoculated subcutaneously in-
to small animals cause death in three to eight days. Intravenous
injections of the ptomaine result the same. Infected meat fed
to animals causes intense gastro-enteric cramps and death, These
'symptoms are the same in man. This form of meat poisoning
follows the consumption of meat obtained front diseased animals.

Owing to the imperceptible decomposition set up by bacillus
enteriditis it is indeed a dangerous organism. It may be present in
ham sausage and fresh meat without any outward indication of its
presence. The milk obtained from diseased animals may contain
the germs and to all appearances it may seem good. Canners of
meat are menaced by such an organism and need inspectors to
examine all meat that is used. The same applies to the canners of
assorted soups, where meat is used for the stock. Manufacturers
of these goods ought to have. a man to inspect and examine micro-
scopically all meats used.

Not all cases of gastro-enteric disturbances prove fatal or
even serious. Nearly every person, at times, is subject to these,
and it is safe to say that ptomaines are responsible in fully one-
third of the cases, but the causes are not understood and are passed
by. It is only when severe cases are brought to the attention of
the public that any criticisms are published. Ptomaines are most
frequently formed in raw material bought in the open market.
Eternal vigiliance is the only safeguard for the manufacturers who
use albuminous material. It is well to state here that such dis-
turbances as we have described may result from other causes ;
overheating incompatible foods, and drinking too much liquor often
cause complications of this nature.

BACII^US MORBIFICANS BOVIS.

This organism was isolated by Basenan from the tissue and
spleen of a cow which died of puerperal fever. It is biologically
and morphologically the same as the Bacterum of swine cholera.
Ostertag found that ptomaine poisoning was produced where the
flesh of cows affected with puerperal fever had been eaten.

It is an actively motile organism, having 8 to 14 flagella, the
rods measuring 0.3 to 0.4^ broad and i to 1.2^ long, generally
united in pairs. (It resembles the typhoid bacillus). Spore for-
mation has not been observed. It stains readily with all ordinary
dyes, but Gram's method is negative.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 179

Colonies on gelatin and agar resemble those of Bacterium coli,
but have a more granular appearance. Gelatin is not liquefied.
Agar stab cultures have white tufts. Bouillon is clouded and a
thin pellicle is formed on the top. Cultures on sterile potato are
yellow and moist and do not darken. Milk is not coagulated.
Grape sugar is slightly fermented with two gases liberated. Carbonic
acid and Hydrogen. Cane sugar is not fermented. Indol and
Phenol are not formed. The bacillus is killed at boiling tempera-
ture and even at 160 F., but the ptomaine is not so destroyed.
Both the meat and the milk from diseased cows will retain the
poison. Very small animals are killed by inoculation or from eat-
ing the flesh ; dogs and cats are not affected. The same precautions
we have mentioned previously .will' prevent poisoning from this
saprophyte.

Plate 59. Bacillus Morbificans Bovis, Flagellated

Magnified 1,000 diameters.

BACILLUS MALLEI.

This is the bacillus which causes glanders and produces a toxic
poison which is fatal to some animals whose flesh is used as food,
viz., sheep and pigs. The horse is very susceptible and man also,
but our object is to show its association with meat poisoning. The
bacillus was dicovered by Loeffler and Schutz and occurs as non-
motile rods 2 to 3/A long and 0.4.". broad, showing bright shining

180 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Mallei, Loeffler and Schutz, (1882)
GLANDERS; MORVE (FR.) ; ROTZ (GERM.), MALLEUS (LAT.).

Origin. It is found in the nodules, ulcers, discharges, etc., of glanders.

Form. Straight or slightly curved rods, with rounded ends, shorter
and thicker than the tubercle bacillus. Usually single, but may grow in
pairs or in short threads.

Motility. Marked Brownian motion.

S population. Bright bodies, considered by Loeffler as the first indi-
cation of degeneration, are often found in the cells, but real spores have
not been found. It is not very resistant to dessication.

Anilin Dyes. It stains unevenly and is rapidly decolored. Carbolic
fuchsin, alkaline aniline gentian violet, or anilin fuchsin, stain well, es-
pecially when warmed. Does not stain by Gram's method.

Growth. Grows best at relatively high temperature. Rapid. Grows
best on glycerin agar.

Plates. Excellent colonies form in a day or two on glycerin agar at
37. The colonies are round, grayish and glistening, having smooth sharp
borders and with granular contents. Colonies cannot be obtained on gel-
atin, as a rule.

Stab Culture. Develops very slowly in gelatin; can be made in gly-
cerin agar.

Streak Culture. On glycerin agar a thick, moist, slimy growth is
formed. On potato it forms a thin, transparent, amber-colored growth,
which later becomes a reddish-brown. On blood-serum yellowish, trans-
parent spots are formed ; these later run together, yielding a slimy, whitish
growth.

Bouillon. Grows readily and abundantly, with diffuse cloudiness ; ring
of slime on the surface. Mallein is the filtered bouillon of the glanders
bacillus. It is analogous to tuberculin.

In milk and acid reaction is produced.

Oxygen Requirements. It is a facultative anaerobe.

Temperature. Grows best at about 37 C. Does not grow readily
above 42 or below 25 C.

Behavior to Gelatin. There is very slight growth at first, but may be-
come accustomed to growth at room temperature later.

Attenuation. Takes place rapidly when grown on artificial media.
If the bacillus is not frequently passed through an animal the virulence
is lost and the organism may die out.

Immunity. Intravenous injections of small amounts of bouillon cul-
ture render dogs immune.

Pathogenesis. Man, horse, ass, goats, cats, guinea-pigs and field-
mice are highly susceptible. Cattle, hogs, ordinary and white mice are
immune. Dogs, rabbits and sheep are slightly susceptible. White mice
fed with phloridxin become susceptible. On inoculation susceptible ani-
mals develop typical glanders. In guinea-pigs death will result in four
to eight weeks. Field mice die within a few days. Enlarged lymphatics,
nodules in liver, spleen, etc. Bacilli are present.

Infection. May occur through wounds inoculation glanders. A man
was accidentally and fatally inoculated with a pure culture in one instance.
The usual source of infection in horses is probably along the respiratory
tract.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

181

granules, which are not spores, although some authors have erred
in so stating. The rods generally appear singly with rounded ends.
Pairs are sometimes seen and rarely threads. Sometimes branch-
ing threads are seen in old cultures. The bacillus stains somewhat
difficultly with ordinary dyes and Gram's method is negative. It
greatly resembles the Diphtheria bacillus in staining on account
of the granules before mentioned.

It is aerobic, facultative, anaerobic: grows at any tempera-
ture between 77 F. and 108 F., best at blood heat, on 5 per cent
glycerine agar.

Plate 60. Bacillus Mallei

Photomicrograph of Bacillus mallei, showing bright, shining granules, resembling spores. Stained with
Loeffier's menthyline blue. Magnified 1,000 diameters.

A characteristic growth is exhibited on sterile potato at 98
F., when moist amber-colored patches make their appearance; these
deepen to a red brown and become thicker, sometimes forming in-
terlaced threads. The surface surrounding the growths turns quite
dark. Acid is produced in media containing grape or milk sugar.
Bouillon is made slightly cloudy with a sediment (and a trace of
indol). Milk is coagulated slowly and separated into casein and
clear whey, owing to the production of acid. No gas is formed
from carbohydrates.

The Bacillus Mallei is destroyed at 2i2F. in a few minutes.
but the specific poison is still virulent. This toxin has been separated
by filtration and is called Mollein and is analogous by the tuber-

182 CANNING AND PRESERVING OF FOOD PRODUCTS.

culin of the tubercle bacillus obtained by Dr. Koch of Berlin. Mal-
lein is used in cases of glanders as a cure and gives good results
in early stages of the disease. It is also used as a means of
diagnosis of glanders in animals.

Sheep and pigs are susceptible and should these be slaughtered
and the meat be consumed, severe cases of poisoning would result.
The poison would remain virulent in the meat even after cooking
orZcanning. Pork is used largely in the preparation of canned
pork and beans. Great care and judgment should be exercised in
the selection of the pork. Good pork has a firm and healthy
appearance in the pickle and the presence of bruises, soft spots or
disease growths should immediately condemn it as not fit to use.
Do not cut out the bad parts and use. the piece, but refuse the whole
tierce if there are any such characteristics. Some packers are tem-
pted to use inferior pork, because the price is a few cents less per
pound. Use only select pork and the general appearance will be a
good indication of its wholesomeness. Of course, the microscope
should be used constantly to determine the character of the albumin-
ous material used in canning, and this applies to the examination
of pork particularly, in the detection of bacteria as well as the
deadly trichinae.

Our readers have now become acquainted with some of the
germs which produce ptomaines and toxins, but there remain a
few belonging to the Pathogenic class, which are at times epidemic
and are familiar to everyone as the cause of special diseases. Their
description and biological characters will be interesting, not only in
connection with out subject at hand, but also from a bacteriological
standpoint.

OTHER PATHOGENIC BACTERIA ASSOCIATED WITH PUTREFACTION
AND FOOD POISONING.

There are a number of bacteria which are pathogenic but are
able to grow on certain food and in water, where they form poisons
which are nearly related to ptomaines. Some of them form toxins
which act as poisons and these may be formed in food which seems
to be wholesome in every respect. It often happens that the bac-
teria are carried in the food and cause epidemics of disease, and
the description of several common varieties will be interesting to
the student of foodstuff for this reason.

TYPHOID BACILLUS.

This organism was discovered by Eberth in the internal organs
of persons who had died of typhoid fever. The bacillus was ob-
served by Dr. Koch in the typhoid abscesses and he made photomi-

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 183

crographs of it. The typhoid bacillus is particularly interesting to
the student of bacteriology and may be obtained in pure cultures
in the manner we shall describe later (article on plate culture).

It occurs as short plump rods with rounded ends, singly, some-
times in pairs, and when grown on potato in threads. It measures
from I to 3/A long and 0.5 to 0.9^ broad. It grows on agar well
at^oS F. and this culture gives the most satisfactory results for
flagella staining. Bright shining spots are seen at the ends of the
bacillus and these were thought to be spores by Gaffky, but such
is_not_ the_c.ase.

It is actively motile, possessing eight to eighteen flagella, which
give the short rods a wonderfully rapid motion. It travels very
fast, turning somersaults. The flagella are long and wavy and
grow out from the whole surface of the bacillus. The isolation of
the bacilli and the proper staining of their flagella is a beautiful
bacterilogical test of skill, and when successfully achieved fits the
student for the most complicated work. Plate 61 is photographed
from a slide prepared from an agar culture and the flagella are
stained by the author's method.

The typhoid bacillus stains well with carbol fnchsin and gentian
violet, but with other dyes the rods do not stain as readily as many
other germs. Gram's staining method is negative. The bacilli
grow in clumps in the tissues and spleen and when stained thus
should remain for one day in Loeffler's methylene blue or Ziehl's
carbol fuchsin and then washed in distilled water. Methylene blue
fades after a time, so the carbol fuchsin or gentian violet is pre-
ferable.

The typhoid bacillus is aerobic, and does not liquify gelatin.
It grows well upon nearly all nutrient media at room, temperature,
but most luxuriantly at blood heat in an incubator. It will grow as
an anaerobe also and thrives fairly well in the presence of CO 2
(carbonic acid gas).

BOUILLON CULTURE. Bouillon is clouded, becoming
slightly acid, and there is a quantity of sediment formed from
which Brieger obtained in 1884 a ptomaine which he named Typho-
toxin C 7 H 17 NO 2 . This ptomaine forms in considerable quantity
in a test tube kept at 98 F. for one week. This ptomaine is
strongly alkaline. Typhotoxin produces salivation, rapid respira-
tion, dilation of the pupils, diarrhoea and death when given to small
animals such as guinea pigs. The experiments have not been tried
on man, but Brieger believes that the specific action of the typhoid
bacillus in tpyhoid fever is due to the production of the ptomaine.

MILK CULTURE. The bacillus grows well in milk and
forms some acid, but does not cause coagulation, hence its presence
is not easily detected. The ptomaine is formed, however, and has

184 CANNING AND PRESERVING OP FOOD PRODUCTS.

Bacillus Typhosus, Eberth, Koch (188O)

BACILLUS OF TYPHOID FEVER/ KOCH-EBERTH's BACILLUS.

Origin. It was first obtained from the spleen and lymphatic glands of
typhoid fever cadavers. It is present in the blood in small numbers ; also
in the feces and urin of typhoid patients.

Form. Rather large rods, two to three times as long as wide, with
rounded ends. The length depends upon the medium on which it grows.
On agar the rods are short; on potato long threads appear. Involution
forms.

Motility. Actively motile, with numerous lateral flagella; fine giant
whips. It may show very little or no motion on prolonged artificial cul-
ture.

Sporulation. Round or oval terminal bodies occur in potato and agar
cultures grown in the incubator for several days. They will not double
stain, and the bacilli which contain them are very susceptible to heat.
These are not true spores, but little masses of condensed protoplasm.
The bacilli are very resistant to dessication, and may retain their vitality
for months.

Anilin Dyes. Do not stain well. Carbolic fuchsin stains very well.
Gram's method will not stain.

Growth. Is less rapid than that of the Colon Bacillus. It grows
slowly at 16-18.

Plates. On gelatin plates the deep colonies are small, round or oval,
yellowish and finely granular, with sharp border. They sometimes show
a dark portion or ring in the center. A protuberance may frequently be
seen on the border, which is surrounded at times with delicate fibrils.
The surface colonies form a spreading, almost transparent film, marked
with delicate, branching lines, and having an irregular, wavy border.
There is no liquefaction.

Stab Culture. Growth is abundant along the entire line of inocula-
tion; is especially so on the surface, spreading there as a thin, grayish
white covering. Acids are produced which cloud the gelatin.

Streak Culture. On agar and on blood-serum a white, moist growth
is formed. On potato, a moist, invisible layer is formed. On alkaline
potato the growth is yellowish; not characteristic.

Bouillon. Is slightly cloudy, not so much so as with the Colon ba-
cillus. There is very little deposit; scarcely any ring or film. Remains
clouded for a long time. It will not grow in bouillon containing 20 c. c.
of N HCL or 50 c. c. of N NaOH per liter, unlike the Colon bacillus.
No indol is produced. In Uschinsky's medium there is no growth.

Milk. Is not coagulated. No gas is formed in glucose media; no
acid in lactose media.

Oxygen Requirements. It is a facultative anaerobe.

Temperature. Grows best at 37 C. ; also grows well at ordinary
temperature. Is killed by exposure to moist heat of 60 C.

Aerogenesis. No acid or gas production on lactose media.

Behavior to Gelatin. Does not liquefy.

Immunity. Injections of dead or living cultures yield an anti-infecti-
ous serum ; injections of the toxin yield an anti-toxic serum. The serum
in the former case will give Pfeiffer's reaction with the Eberth, but not
with the Colon bacillus.

Pathogenesis. Rabbits are usually killed by intravenous injections.
It is usually fatal to guinea-pigs when injected into the duodenum or the
peritoneal cavity or when introduced into the previously alkalized stomach.
Guinea-pigs are killed bp subcutaneous injections also. Abscesses are pro-
duced in dogs and rabbits by the same method of infection. It may pro-
duce abscesses in man. Cultures killed with chloroform or by heating for
one hour at 54 are fatal to guinea-pigs in doses of 3-4 m. g. per 100 g.
body weight.

Infection. Takes place commonly through the mouth by means of
water, food, soiled articles, etc. It may be transmitted through the air as
fine dust. Carried by flies and other insects.

[

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 185

Plate 61. Typhoid Bacillus Flagellated

Magnified 1000 diameters

Plate 62. Typhoid Bacillus, showing Agglutination

Magnified 500 diameters.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 187

been the cause of severe poisoning I have no doubt. Milk is a great
carrier of the disease and many epidemics have been traced to
it. The contamination is usually made through the water used in
rinsing the pails, especially if the water is obtained from wells or
springs where the bacilli have found entrance. Many farm wells
are close to closets and cesspools and become contaminated from
the faecal matter of typhoid patients. Epidemics have been traced
directly to this source and there are official records of a number. In
1870 Ballard investigated the epidemic in Islington, where 167 peo-
ple contracted the disease, and the investigation led to the discovery
that the milk used by these people was obtained from a farm where
the well was contaminated by rat holes connecting with the closet.
The farmer had a case of typhoid fever and the well water was
used to rinse the pails.

The fever broke out in the prisons at Strasburg in 1890, and
the disease was traced to the milk supply, \vhich came from a place
w r here the fever was epidemic. Rowland, in 1892, found the living
bacteria in what is known as "Dahi," which is an Indian milk
comestible.

Since milk is one of the principal ingredients of so many fine
food products, especially of the cream soups, it is perhaps wise to
advise the use of "'Pasteurized" milk, for this method destroys all
such germs as the Typhoid bacillus long before they have oppor-
tunity to multiply and form ptomaines. The great danger from
using raw milk lies in the possible contamination by disease germs,
and while these will be destroyed in the sterilizing process, the poi-
son still remains in certain quantities, and may cause sickness vary-
ing in violence according to the amount of poison present. Per-
haps the amount of poison will be so slight as to cause no appre-
hension, yet the food product will not give satisfaction.

POTATO CULTURE. A characteristic growth of the
typhoid bacillus when planted on sterilized potato; it is almost in-
visible and threads are formed which have a beautiful serpentine
motion. The potato is generally slightly acid and this is favorable
for a typical growth.

GELATIN PLATE CULTURE. The surface colonies are
at first small and yellowish, punctiformecl, becoming round and
slightly notched and shining. The periphery is clear and trans-
parent, slightly gray; the centers are opaque and slightly elevated.
When magnified about seventy-five times young colonies are color-
less and smooth bordered; later lines are visible like bands ex-
tending from the center; these gradually deepen like folds and
look like hen tracks. The colony has a golden yellow color and
is very pretty. The deep colonies are whetstone in shape and yel-
low, with smooth borders and slightly gray.

188 CANNING AND PRESERVING OF FOOD PRODUCTS.

AGAR CULTURE. The surface colonies are irregularly
round, smooth bordered, gray and shining, and when magnified ap-
pears bright yellow in color, becoming darker towards the center
with transparent edges. Dark irregular lines run out from the cen-
ter and give the colony a beautiful appearance. The deep colonies
are yellow and finely granular ; they are opaque, whetstone shaped,
looking something like an almond. The agar streak is even border-
ed, slightly elevated and slightly gray, with a lustrous appearance.
After a time the color changes to yellow.

The study of this bacillus in cultures is most interesting and
instructive and if care is exercised there need be no fear in cul-
tivating and handling it. . There are so many points of interest con-
nected with its life, its manner of growth and its behavior under
certain conditions, that the study of its biological characteristics
will enable the student to intelligently investigate any other or-
ganism.

Typhoid bacilli produce a poison which interferes with their
reproductive power, so that cultures will cease growing after a time
and the bacilli will not be as actively motile as when planted in
fresh nutrient media. When growing in the human body the poison
is carried away in the blood and it is possible to determine quite
early if the patient is attacked by the fever. The test is made
with the serum from the blood and is called the agglutination
test, which may be described as follows : A homogeneous sus-
pension of the bacilli is made first. This is done by taking a plati-
num loop full of the germs from a culture about one day old, which
has grown on hard agar; the germs are loosened from one an-
other by rubbing them against the side of a test tube containing
I c.c. of bouillon. When there is a perfect separation and even
distribution the mixture is termed a homogeneous suspension, and
a small quantity must be examined under the microscope with a
magnification of 500 diameters to make sure that there are no
clumps, and that all the bacilli are actively motile. This being
ascertained, different dilutions are made of the blood serum, and
each dilution is inoculated with typhoid bacilli. This is done on a
cover-glass which is then inverted over a cell in a hollow-ground
slide and sealed to avoid evaporation. The hanging drop is then
placed in the incubator for various lengths of time, and occasional-
ly removed and examined under the microscope to ascertain if
the bacilli have gathered in bunches. If the blood has been taken
from a typhoid patient, the agglutination is almost sure to take
place even in weak dilutions. A positive aggultination is fairly
conclusive evidence of enteric fever. See Plate 62.

Persons who have had typhoid fever remain immune for a
considerable time, and in some cases for life. Blood from such

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 189

persons sometimes gives a similar reaction as the blood from a
typhoid fever patient, but not quite so marked, especially in the
great dilutions.

The examination of water to determine the presence of typhoid
is quite difficult, because there is a class of bacteria called Coli
commune (of which there are a number of species), which closely
resemble the true typhoid bacilli. These species are found in the
faeces of healthy persons and water is usually condemned as unfit
for drinking purposes, when any of these are found, because it in-
dicates that it is contaminated with sewage.

The biological characteristics of the typhoid bacillus may be
thus summed up : It is aerobic and facultative anaerobic, clouds
bouillon, does not coagulate milk, and the reaction is amphoteric,
does not form spores, is not chromogenic, produces sulphuretted
hydrogen in abundance, ordinarily does not produce inclol, produces
some acid in grape-sugar-bouillon, produces no gas in sugar agar
and grows fairly well in an atmosphere of carbonic acid gas. It
produces a ptomaine which is a powerful poison. The study of this
organism is most interesting to the food chemist and investigator.

Typhoid is commonly epidemic, and it is no doubt carried
from one location to another in food and water, which gives it
a place in the catalog of dangerous bacteria associated with food
spoilage.

CHOLERA BACILLUS.

The germ which produces Asiatic cholera is called by the fol-
lowing names : Comma Bacillus, Vibrio cholera, Spirillum cholera
and "Bacille vir gule" (French). The name comma bacillus was
given to it on account of the bodies often seen at the end of the
germs, which are incorrectly described by Huppe as arthrospores.
The germination of these bodies has not been positively observed,
but they cause the germ to look like a comma (,) hence the name.

It is seldom that this terrible foe of man gets a strong hold
in America, yet there have been some severe epidemics which car-
ried whole families and communities out of existence in a few clays.
In various parts of Asia it is epidemic nearly all the time. It is
said that in Saigon, Asia, there are always a few cases, and at
times it spreads, carrying death to thousands.

Not until 1884 was it known positively just what was the
agent of this dreaded disease. Dr. Koch of Berlin made the dis-
covery of the germ and showed how it was carried in water and in
food from one place to another. Dr. Koch carried on his researches
in Egypt and India, and other eminent bacteriologists, both from
Europe and America, have made searching investigations of the
micro-organism and have studied its biological characteristics to

190 CANNING AND PRESERVING OF FOOD PRODUCTS.

such an extent that the disease is now combated with more success
than formerly when the true cause was shrouded in mystery.

The disease makes its appearance in every country occasional-
ly, the specific organism being carried from infected districts by
travelers, in articles of food and clothing, etc. The organism is
one of the few which produces several ptomaines and toxic poisons,
some of which are very dangerous. The specific action of these poi-
sons are varied, and violent sickness and even death may result
from them if taken in food which has been contaminated. Of
course there is danger only when the disease is rife in certain lo-
calities, and when food stuff is obtained from such places.

Plate 63

The Cholera spirillum is a curved rod measuring from 0.8 to
2p. in length and 0.3 to 0.4^ broad, the ends being rarely in the same
plane, so that when several are united they resemble a corkscrew.
When seen singly they resemble a comma and when seen in pairs
may form the letter (S) 'or the letter (O). The (S) forms are
quite common where the growth is rapid. The long corkscrew
forms are seen generally in hanging drop cultures growing in favor-
able temperatures or conditions. Old cultures assume varied forms,
bearing little resemblance to young cultures. Involution forms

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 191

with spherical bodies are produced, which are thought to be spores
belonging to the so-called anthrospore type of spore formation, but
no one has observed the germination of these bodies. It is a motile
organism having a single terminal flagellum; sometimes two flagella.

Milk is a good medium for growth and is coagulated with the
production of lactic acid.

Indol is formed abundantly in nutrient media containing pep-
tone or albumen. The presence of indol in cultures may be demon-
strated by adding a minute quantity of muriatic or sulphuric acid
to the medium, when a rose-red color will make its appearance and
is known as the nitrose indol reaction. In all cultures containing
albumen indol is formed first and then the nitrates are converted into
nitrites. This is also true of at least two other species of bacteria.
All cultures of the cholera have a disagreeable, sickening odor, but
these are not specially characteristic.

Plate 64. Bacillus Coli Communis, showing Flagella

Stained by the author. Magnified 1,000 diameters.

Media containing either milk-grape or cane sugar favor the
production of lactic acid, which is dextrorotatory.

A beautiful chemical reaction is seen when cholera is grown in
a test tube containing litmus milk ; a pale blue pellicle is formed on
the top, under which is a stratum of red, while the lower portion will
be entirely decolorized.

Sulphuretted hydrogen (H 2 S) is formed abundantly in peptone
bouillon and also in sterilized egg albumen. Cholera germs are
not very resistant to unfavorable conditions. They are killed in
water heated to 130 degrees F., and when frozen they die within a

192 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Coli Conuiiimis, Kscherich (1885)

BACTERIUM COLI COMMUNE; THE COLON BACILLUS/ EMMERICH'S BACILLUS/

B. NEAPOLITANUS.

Origin. Found in the intestinal contents of man and animals, es-
pecially in the colon; also occurs in the discharges of healthy infants and
in summer diarrhoea. It frequently accompanies the Comma Bacillus in
the discharges of Asiatic cholera. It resembles in many respects the ty-
phoid fever bacillus.

Form. Short, narrow rods, varying in length from coccus-like forms
to rods four to six times as long as wide. Usually found in pairs, may
form threads.

Motility. Depends upon the medium, age and temperature. It has
diffuse flagella and giant whips.

Speculation. Has not been observed.

Anilin Dyes. Stain readily. Grain's method will not stain. Bi-polar
stain frequently occurs; also plasmolytic changes, as in potato cultures.

Growth. More rapid than that of typhoid bacillus.

Plates. On gelatin plates dull-white surface colonies, with irregular
border and markings in the outer zone, are formed. These colonies are
fiat, spreading and aniso-diametric. The deep colonies are round or oval
in form and of a yellowish color ; they are frequently divided, forming
lobulated masses. The round colonies have usually a yellow granular cen-
ter surrounded by a colorless homogeneous ring. Does not liquefy.
Strong odor of indol and amine. Owing to the ammoniacal reaction, the
gelatin deposits a cloudy precipitate between the colonies and along any
scratches that may occur on the glass plate. These characteristics differ-
entiate it from the typhoid bacillus.

Stab culture. Along the line of iroculation the growth is rather en-
ergetic. On the surface a white film with wavy border is formed.

Streak Culture. On agar, a moist, white, spreading growth is formed ;
old cultures sometimes show needle-shaped crystals. On potato, an abund-
ant, yellowish, moist slowly spreading growth is formed.

Milk. Coagulates in one or two days ; sometimes a week or more may
be required.

Bouillon becomes very cloudy, with heavy sediment; at the. surface a
thick ring may adhere to the glass ; a broken pellicle may form. Marked
indol reaction.

Oxygen Requirements. It is a facultative anaerobe.

Temperature. Grows best at about 37 C, but will grow well at or-
dinary temperature.

Behavior to Gelatin. Gelatin is not liquefied.

Aero gene sis. When glucose is present carbonic acid and hydrogen
are produced abundantly. Acid and gas may be. formed in lactose media
unlike the typhoid bacillus.

Pathogcncsis. Guinea-pigs are very susceptible ; rabbits less suscep-
tible, and mice are insusceptible. Diarrhoea, collapse and death are pro-
duced in one to three days by small intravenous injections or injections
into the abdominal cavity. The small intestine is hyperemic, more or
less intensely inflamed ; serous exudates may be present. The bacilli are
abundant in the blood, in organs and on the peritoneum. Subcutaneous
injections produce only a local abscess usually; is not usually fatal.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

193

few days. Drying kills them in a few hours. Weak antiseptics
destroy them. They require frequent transplanting in favorable
nutrient media to keep them for any long period.

The bacterial poisons formed by the cholera germ are very
powerful. Old bouillon cultures, when filtered through the Cham-
berland filter has all germs removed, but the poison in solution kills
small animals, such as rabbits, mice, guinea pigs, etc.

Putrescin and cadaverin are two ptomaines extracted by Brie-
ger from cholera, but are not very poisonous. Methyl-guanidin is
another, but is very poisonous, causing muscular tremors and death.
"Toxopepton" was obtained by Petri as a poisonous proteid which
killed guinea pigs in a few hours in doses of 36 grams per kilogram
weight.

Plate 65. Bacillus Coli Communis

Magnified 1,000 diameters.

A substance insoluble in water and acids, but soluble in alkalis
and ether is obtained by a method discovered by Winter and Lesage.
When evaporated from the extract, it is oily and becomes yellow like
fat on cooling. Small doses are fatal in a short time when fed to
small animals.

BACILLUS COLI COMMUNIS OR COLON BACILLUS.

This very common bacillus is not a single species, but a family
comprising a number of species very closely resembling one another
and differentiated only by most careful study. It is a question
whether there are distinct species or whether the one species changes
in its morphological and biological character under certain condi-
tions, thus causing confusion. Various textbooks attempt a separa-
tion of species according to their different pathogenic power, but

194 CANNING AND PRESERVING OF FOOD PRODUCTS.

in my own researches I have been unable to make a clear distinction
between any germs of this family. The Coli communis is always
present in intestines of healthy man and various animals, and is
nearly always found associated with other bacteria in a number of
diseases, such as suppurative processes in the internal organs, in-
fectious enteritis, ulcerated liver, puerperal fever, meningitis, etc.

The bacillus resembles the typhoid bacillus so closely in its
form, size and its growth on various culture media as to make its
differentiation a nice bacteriological problem.

The differences may be stated as follows : It is not so actively
motile as typhoid, has fewer and shorter flagella, it develops more
luxuriantly on all media, and the growth on potato is visible, while
that of typhoid is not. It coagulates milk, giving marked acid
reaction, while typhoid does not and the acid reaction is only slight.
It forms considerable gas in media containing glucose, lactose and
saccharose. Colonies are pink on (alkaline) agar and gelatine
media containing lactose and litmus tincture, while those of Typhoid
are pale blue.

It produces indol (in peptone solutions) more freely than
typhoid. Typhoid as a rule does not produce indol, but it is some-
times formed in peptone solutions.

Agglutination test is generally negative. Pfeiffer's serum re-
action with typhoid blood serum as described under typhoid is nega-
tive with the Coli communis.

Tyrotoxicon is supposed to be a poison formed by this microbe,
although the evidence is not positive. In 1886 this poison was first
discovered in milk which had poisoned a number of persons at Long
Branch. The milk had been exposed to unusual conditions, favor-
ing the growth of the Colon bacillus probably. Vaughan reported
an interesting case of poison from tyrotoxicon, known as the Milan
case. The symptoms were rapid pulse, breathing rapid, burning
sensation in the throat and stomach, abdomen retracted and severe
throbbing in the abdomen. The contamination of milk from germs
which were present in decomposing matter under the floor was found
to be the cause. Vaughan and Novy found the poison in numerous
samples of poisonous ice cream and custard. Novy says that "Un-
doubtedly there are many forms of the Colon bacillus which fre-
quently find their way into milk and, on account of the toxins con-
tained within their cells, they render this and various other foods,
of which milk is a constituent, more or less poisonous." The potas-
sium compound of tyrotoxicon is not decomposed in a temperature
under 265 degrees F., so that foods containing milk and cheese
which have been exposed in any way to human or animal excreta or
to contaminated water are liable to have this poison formed by the
Bacillus coli communis. The poison is present in the human

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 195

faeces, but ordinarily passes away without any serious results, as it
is formed past the danger line.

Tyrotoxicon may be formed by other agents, but the accurate
knowledge of its origin is not yet thoroughly investigated. It is
a powerful poison and many fatalities have followed where food
containing it has been eaten. It is generally found in milk, ice
cream and cheese, from which it derives its name.

TETANUS.

Tetanus or lockjaw is a disease produced in man and nearly all
domestic animals by a widespread germ found in garden soil, ma-
nure heaps and saltpeter beds. The horse is the most susceptible
domestic animal, but cows, sheep, pigs and goats are sometimes at-
tacked. Man is very susceptible to this disease, which is considered
to be one of the most dangerous and deadly.

The germ produces several very powerful ptomaines, which
have been isolated by Brieger in crystalline forms; Tetanine, which
decomposes in acid and remains unaltered in alkaline solutions, wilf
in itself produce lockjaw when injected into the tissues of animals;
tetanoxin, which produces tremors and paralysis, followed by con-
vulsions; tetanotoxin, which induces lockjaw, accompanied by a flow
of tears and saliva; and spasmotoxin, which produces spasms and
convulsions. Late investigators have formed the opinion that the
crystalline substances obtained by Brieger owed their poisonous
properties to the toxin of tetanus and that they were not of them-
selves poisons.

The flesh of animals suffering from disease is apt to contain
such elements, and if such flesh should be used in the preparation of
food products, either in soups, extracts or canned meats, the direful
results may be far reaching. Packers who use meats can thus un-
derstand how necessary it is to be careful in their selection ; any un-
natural appearances should be a sufficient reason for rejecting any
lot of meat which they may be using.

The poison of the tetanus germ has been used by natives of
the New Hebrides, according to Ledantec, on arrowheads made of
human bones, which they first cover with resin and smear with the
slime found in swamps; the slime no doubt contains the tetanus
bacilli in large numbers and even a slight wound from such weapons
of warfare would prove fatal.

The tetanus bacillus when magnified one thousand diameters is
seen to be slender, with a large spore in the end of the rod which
does not readily take a stain. In measures from 3 to 5 /^ in length
and 0.3 to 0.5 p in width. In cultures it is seen to grow in threads
and often appears without the spore, but usually the spore is present
in single rods and gives the germ the appearance of a nail, from

196 CANNING AND PRESERVING OF FOOD PRODUCTS.

Bacillus Tetani, Nicolaier (1884)

TETANUS, LOCK-JAW; WUNDSTARRKRAMPF (GERM.); TETANOS. (FR.)

Origin. It is found in animals that die of tetanus after inoculation
with earth ; in traumatic tetanus of man and animals ; in head tetanus ;
tetanus of new-born; is present in the intestines.

Form. Large, narrow rods, having rounded ends ; may form threads.

Motility. It is motile. Many curly flagella, also giant whips.

Sporulation. Spores are formed rapidly at 37. Terminal spores
are formed, with enlargement-drum-sticks.

Anilin Dyes. Stain readily. Gram's method may be used.

Growth. Slow.

Plates. Colonies develop in gelatin at ordinary temperature in four
to seven days; these resemble those of the Hay bacillus. The gelatin
slowly liquefies, and gas is produced. On agar plates the colonies have
the appearance of faint clouds ; when examined under the microscope these
are seen to be oval, partially surrounded by a whorl of extremely fine
threads.

Stab Culture. No growth at the upper part of the tube. In glucose
gelatin tubes cultures show a cloudy growth along the line of inoculation,
which radiates outward into the gelatin, resembling that of the Root ba-
cillus. The gelatin is eventually liquefied. Gas bubbles are present. In
glucose agar at 37 the growth is sometimes indistinct, showing radia-
tions.

Streak Culture. On glucose agar growth is rapid and practically in-
visible.

Bouillon. It becomes diffusely cloudy at 37, but after several days
the growth settles to the bottom in the form of a scarcely visible sediment.

Glucose Gelatin, colored with litmus. Becomes permanently lique-
fied at 37, a very small sediment is formed. The culture remains blue,
thus showing that there is no acid formation.

Milk. Grows well in milk, but produces no change. Starch is not
inverted. On potato, the growth is invisible.

Oxygen Requirements. It is an obligative anaerobe, growing in va-
cuum, hydrogen, carbonic acid and nitrogen.

Temperature. Grows best at about 38 C. Will not grow below 16 C.

Behavior to Gelatin. Liquefies.

Aerogenesis. Produces gas; has disagreeable odor; H 2 S.

Attenuation. There is a loss of virulence by culture.

Immunity. lodin trichlorid; thymus bouillon cultures; injection of
filtered cultures ; of purified toxin ; milk of immunized goat ; blood-serum
of rabbits, dogs, sheep, horses, which have been artificially immunized.
The tetanus toxin is destroyed by the nucleohiston from the thymus gland.

Patho gene sis. Man, horse, sheep, young cattle, goats, guinea-pigs,
white rats and white mice, are susceptible. Dogs and rabbits are less
susceptible. Chickens and ducks, immune. It is not present in the blood,
but occurs in small numbers at the point of inoculation; may be absent
entirely at times. Products are intensely poisonous. A guinea-pig may
be killed by 0.002 c. c. of a filtered bouillon culture and a dose of 0.0002 c.
c. may kill a mouse. Disease cannot be produced by pure tetanus spores.
Mixed infection.

Infection. Occurs through wounds. The poisoned arrows of the
New Hebrides contain tetanus and malignant edema spores.

Diagnosis. On account of its scarcity and the presence of other ae-
robic and anaerobic bacteria, the bacillus is hard to detect. The pus should
be taken from the wound by means of a sterile drawn-out glass tube
pipette and transferred to glucose litmus gelatin. A loopful of this dilu-
tion should then be transferred to each of eight or ten tubes of liquefied
glucose agar. These should be poured into Petri dishes and developed in
hydrogen. The characteristic colony is oval, surrounded on one end by a
whorl of threads.

The original glucose litmus gelatin is developed at 35 ; a portion of
this is injected under the skin of a white mouse or a guinea-pig.

A portion of the pus should be stained direct, then examined for
tetanus bacilli and for the terminal spores (drum-sticks). (From Novy.)

DECOMPOSITION CAUSED BY MICRO-ORGANISMS.

197

:/* . r

m % J *%

^% m

Plate 66 Bacillus Tetanus Flagellated

Magnified 1,200 diameters.

Plate 67. Bacillus Tetanus

Magnified X 1,000. Photomicrogrash from Slide Prepared by Author from Bouillon. Stained with Carbol
Fuchsin. Large Terminal Spares are shown, which give to the Bacilli the Appearance of Nails or Pins. It is
sometimes called the "Nail Head Germ."

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 199

whence it received the name of "the nail-head germ." The spore
is much greater in diameter than the width of the bacillus and gives
it the appearance of a pin or a clove or an eyescrew. Spores may
be seen in the long threads at times.

The spores remain alive and virulent in culture media for more
than a year (in a dark place), but are not able to live through a boil-
ing temperature of 212 degrees F., applied for ten minutes. Five
per cent, phenol solution kills them in one day, but if muriatic acid
is added the spores perish within a couple of hours. The vitality
may be tested by transplanting after exposures to heat and antisep-
tics. Bichloride of mercury i-iooo destroys them within three
hours, but when muriatic acid is added to the mercury they perish in
less than an hour.

The young bacilli may be stained for flagella and the number is
surprisingly large and it is difficult to count them. Votteler claims
to have counted 50 to 100 growing out from the entire surface.
The bacilli are not actively, motile which is more surprising from
the fact that other germs with one-fifth the number of flagella are
very active. There is, however, a distinct spontaneous motion
which may be seen in the hanging drop cultures.

Tetanus bacillus is strongly anaerobic, even small quantities of
oxygen interfere with its growth, especially if it is cultivated from
the animal body or wounds which have become infected. After
transplanting a number of times in nutrient media the tetanus germs
become less susceptible to oxygen and have been cultivated quite suc-
cessfully in the presence of other organisms belonging to the class of
aerobes. When grown as an aerobe, pure cultures lose much of
their virulence. This is also true of other anaerobic bacteria be-
longing to the pathogenic classification.

Bacillus tetanus grows well at 98 to 100 degrees F. and slowly
at room temperature. At 50 degrees F. there is no growth. When
the germs are very virulent there is only a moderate growth, even
at 98 degrees F., but cultures that have been frequently transplanted
grow most luxuriantly. Many pathogenic bacteria seem to change
in their nature and develop the characteristics of the putrefactive
species and lose much of their virulence after repeated transplanting.
These germs when inoculated into susceptible animals become high-
ly virulent again.

The cultivation of tetanus in artificial media is made regular
anaerobic culture apparatus by using hydrogen as an atmosphere af-
ter driving out all oxygen, but the least expensive method is the ab-
sorption of oxygen by pyrogalic acid in the presence of potassium
hydroxid, enough to make the acid alkaline, when it will darken,
first brown and then black.

200 CANNING AND PRESERVING OF FOOD PRODUCTS.

Animals which have tetanus will have the active poison
throughout the circulating system. The blood and gland secretions
contain it in sufficient quantities to set up the disease in other ani-
mals which are inoculated with the blood or pleural exudes. Strange
to say, the tissue of diseased animals seems to have to be devoid of
the poison, except at the point where the germs had gained entrance
i e., the wound or seat of inoculation. The poison becomes inert if
subjected to temperatures varying from 150 to 212 P., but if it is
dried at ordinary temperature first it retains its virulence and with-
stands much higher temperatures.

When the germs gain entrance into a living animal or man
through a wound the point of entrance will heal over and appear to
be getting well. This places the tetanus bacilli in an anaerobic and
they soon begin to multiply, the period of incubation being from
one to twenty-five days. If lockjaw results after one day there are
probably a number of pus germs in the wound, which use up the
oxygen from the surface and place the tetanus bacilli in their favor-
able anaerobic condition, in which case the sufferer has small chance
of recovery. The longer the period of incubation the greater is the
chance for recovery, because the system becomes more or less armed
against the poison by gradually accommodating itself to its influence.

The anti-tetanic serum is prepared from the blood of inoculated
animals and has been injected into the blood of victims of tetanus
with satisfactory results. The serum is known to produce im-
munity, and hundreds of positive cures are recorded from its use.

There is no doubt but that the flesh of animals suffering with
lockjaw contains large quantities of the toxin in the juices, and if
used as food either in manufacture of canned meats or soup stock,
Witt cause severe sickness and possibly death. It is certainly a
dangerous malady, from the fact that an animal may have the di-
' sease during the period of incubation and show no outward sign of
its presence. There is always an exceedingly abundant production
of H 2 S (sulphuretted hydrogen) where the germs are grow-
ing and indol is produced, so that infected food products will show
signs of contamination if care is exercised in inspection.

BACILLUS DIPHTHERIA!} COI^UMBARUM.

This is a non-motile organism, about 2/* in length and 0.5^
broad, having rounded ends. There is no spore formation, and it
is aerobic and does not liquefy gelatin. The flesh of chickens suf-
fering with this disease presents a flabby appearance and is usually
somewhat discolored. Chickens, game birds and pigeons are sus-
ceptile, and it is very contagious among them.

There are numerous cases of ptomaine poisoning on record due
to bacteria which have produced the poison in chicken ; indeed, this

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 201

is quite common. One case happened three years ago in Aspin-
wall, Pa., at a chicken and waffle supper. Fully twenty persons
were made violently ill from eating the chicken. One case of
poisoning from chicken soup came under my notice during a visit to
San Francisco. In this case the soup had been canned and was
perfectly sterilized, yet the ptomaine remained. Just what organ-
ism caused the trouble I do not know, because I was not in a position
to make a thorough examination, but part of the soup when fed to a
clog caused the animal to become violently sick. There is no doubt
but that Bacillus Diptheriae Columbarum is one organism which
produces a powerful toxic poison and that chickens suffering with
diptheria have the poison in sufficient quantities to produce severe
cramps and nervous prostration with symptoms of paralysis in per-
sons who partake of the cooked flesh. There is no doubt that such
diseased poultry is sometimes sold on the market, and packers of
potted chicken, chicken soup and canned chicken should be extreme-
ly careful in selection. If careful inspection is made, evidence, of
disease will almost invariably be indicated by general appearance
and color.

Bacillus Diptheria Vitulorum is another organism affecting
calves and is found in the mouth, lungs and intestines. It is usual-
ly in filaments, and is several times as long as it measures in breadth.
It is non-liquefying on calf blood serum, which seems to be the only
medium on which a culture can be obtained.

The flesh of a calf suffering from diptheria is not sound in
color, nor is it firm, and the usual precautions will suffice to aid the
inspector in judgingjt.

There are a number of diseases affecting animals and poultry
which are due to pathogenic bacteria, but I will merely mention a
few of them, as our readers are pretty familiar with the subject by
this time. Vibrio Metschnikovii, which is the organism producing
one kind of chicken cholera. Bacillus of Chicken Cholera, Hog
Cholera Bacillus, Anthrax Bacillus, and various organisms which
produce blood poisoning.

It must not be supposed by our readers that meats and albumi-
nous food materials, which contain poisons due to the organisms we
have been describing, are constantly put on the market and sold to
unsuspecting packers. It happens only rarely that such material is
used, and our object has been to furnish complete information on
this subject to teach packers the necessity of careful inspection, both
macroscopically and microscopically. Ptomaine poisonig from
canned goods is extremely rare in comparison with such complica-
tions from other sources, but we hope to decrease these by fully de-
scribing the various organisms known to produce poisons and by
pointing out the danger in using unsound material.

202 CANNING AND PRESERVING OF FOOD PRODUCTS.

Every packer should take a lively interest in this subject, be-
cause cases of Ptomaine poisoning, although rare, are a source of
considerable annoyance to the whole industry. Unreasonable bills
are introduced in the legislatures of various states which cause the
packers trouble. I have referred in former pages to the "Canned
Goods Dating Bills."

PTOMAINES AND TOXINS.

Ptomaine Poisoning and Its Bearing on the Food Industry.

The word ptomaine springs from the Greek word (ptoma)
ptoma, which is pronounced (toma) and means a dead body. This
name was given to a group of poisons obtained from cadavers by
Selmi, a noted Italian chemist and toxicoligist. For many years
the term was applied to all bases which combined with acids and
formed salts as a result of bacterial activity, and these bases were
regarded as poisons, but later investigations have demonstrated that
ptomaines are not all poisons, in fact only a few of them may be
considered as dangerous. Many of the ptomaines owe their poison-
ous properties to a more powerful poison, which is termed a toxin,
and this is a product of the putrefactive and pathogenic bacteria,
many of which we have described. Novy describes a ptomaine as,
"an organic chemical compound, basic in character, and formed by
the action of bacteria on nitrogenous matter. On account of their
basic properties, in which they resemble the vegetable alkaloids,
ptomaines may be called putrefactive alkaloids."

They are formed in the putrefactive processes on both vege-
table and animal matter of albuminous nature by the agency of bac-
teria. When such matter is attacked by bacteria, the various mole-
cules containing carbon, nitrogen, oxygen and hydrogen, are upset
and new atomical relations are formed by the cleavage, in the vari-
ous steps of total dissolution. The final results of bacterial activity
is the fomation of carbon clioxid, ammonia, and water, and it is be-
tween the first and last stages that the alkaloids are formed.

In some cases of food poisonings, toxins have been isolated as
well as ptomaines, so we will include both in the discussion of this
subject.

The increase of food poisoning in recent years has been de-
clared by some eminent authorities to the increased consumption of
preserved foods, the claim being made that inferior stuff, which
would not be purchased in the raw state on account of its appearance
and partial decomposition is easily made to look well by skillful
chefs and manufacturers of canned foods, and that these contain the
poisons elaborated by harmful bacteria, and that these poisonous
alkaloids do not lose their potency in the cooking and sterilizing

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 203

processes. Canners have been accused of using partially decom-
posed materials, both knowingly and ignorantly, and the responsi-
bility for a large number of food poisoning cases, has been charged
against them. For the most part ignorance has been charged be-
cause they are not familiar with the scientific principles of their busi-
ness, and do not realize the dangers lurking in decomposing ma-
terial, due to vital activity of bacteria.

While there may be extremely little truth in these statements
and while we must admit that the canners and preservers of food
products have been guilty of gross ignorance, and are not even today
well informed on these matters, we cannot help making the state-
ment that the charges are very much overdrawn and that the ignor-
ance displayed by the canners could hardly surpass that displayed by
the list of physicians, who are for the most part to blame for the
charges of ptomaine poisoning against canned goods. In order to
write intelligently on this subject, I have made it a point to question
a number of physicians concerning ptomaines and toxic poisons, and
their answers showed that they were as a rule ignorant of their
names and origin.

I do not mean to cast reflections upon physicians in general;
many of them are conscientious in their diagnoses and would not
place the blame on canned goods without investigating the cause
carefully. There are others, however, who jump at conclusions and
furnish the press with information which may be absolutely untrue.
Inlhis manner false statements have been circulated throughout the
civilized world and the preserving industry has had to bear the
brunt in many cases.

It is not true that canners and preservers are in the habit of
using partially decomposed material. It is impossible to make fine
goods from anything but the very best raw material, and all reput-
able firms are extremely careful in selecting the very best, and their
contracts with farmers are strict.

We must admit, however, that there are some packers who are
ignorant of the dangers of which we are writing and there may be
some who are unscrupulous, but the goods turned out by these
manufacturers are very inferior, often highly colored to cover up
imperfections, and the quality is very poor. There have been, and
probably are today, a few packers who come under these two classes.
A good Natural Pure Food Law will be a great blessing to the
whole industry, and will eliminate all goods artificially colored, and
unnecessarily preserved with antiseptics. When this law is made
effective, the honest and well informed food preservers will enjoy
a ready market for all their goods, and will not be embarrassed by
persecutions.

204 CANNING AND PRESERVING OP FOOD PRODUCTS.

When all, or nearly all, goods of inferior quality are elimin-
ated, there will be renewed confidence in manufactured food pro-
ducts, and the worry of putting up goods at home will form a part
of past history. The superiority of manufactured food products
over home made goods is conceded by the intelligent consumers, for
the reason that only men of great skill are employed to produce
goods of fine quality, and by the use of improved machinery the
little imperfections seen in the home goods are overcome.

The progress now being made in the science of bacteriology,
and the research work in physiological chemistry, are furnishing
considerable literary material, which is being published to en-
lighten manufacturers on these subjects. The problems of spoilage
are now taken up carefully, and the various ptomaines and toxins
are becoming known, also the bacteria which are responsible.

The isolation of ptomaines and toxins requires great skill and
patience, and there are only a very few men who are far enough
advanced to make these analyses, and our readers will be able to
judge of this from the examples we will give as illustrations.

We will not attempt in a work of this kind to give a complete
list of all these poisons (and methods of extracting them), but if
anyone desires to enter into the study in a comprehensive manner
we will be glad to furnish material for such research. Manufac-
turers who have suits brought against them on account of reported
ptomaine poison found in their goods need some direct information
on the methods employed by chemists in isolating these poisons, in
order to supply their lawyers with the necessary questions to be
asked the physicians who testify in such cases. The methods de-
scribed here will show how complicated the analyses are and it is
safe to say that they will be sufficiently advanced to enable a good
attorney to overthrow mere guesswork of many physicians who
testify in these cases. Not long ago a certain well-known firm was
called upon to make defense in suit for damages ; the parties claim-
ing ptomaine poisoning where canned goods were used at a meal,
after which one member of the family was taken violently ill.
Three doctors were called in, and worked all night to save the wo-
man, and succeeded, but the family being poor, and the doctor's bills
large, a suit for damages seemed to be a good way to even up. \Vhen
the case came up, and the attorney, (armed with the chemical meth-
ods for extracting ptomaines) asked the doctors the various ques-
tions, the case seemed ridiculous and was thrown out of court. In
July, 1903, when the writer was in St. Paul attending the Conven-
tion of State Food Commissioners and Chemists, an article ap-
peared in the papers stating that a family had been poisoned with
food containing a ptomaine, and the physician who attended the pa-
tients was quoted as authority for the statement. Samples of the

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 205

food and some of stomach contents were sent to the bacteriologist
of St. Paul and the analysis proved it to be a common mineral
poison and not a ptomaine. The cooked beefsteak was found to
contain this poison. Hbw the poison happened to be there no one
was able to learn, but the point I wish to make is that ptomaine
poisons are not always responsible.

These cases demonstrate the hasty conclusions often reached
by doctors. To be sure they furnish sensational reading, but the
manufacturer of foodstuffs is put to considerable worry and ex-
pense to defend himself when suits are entered against him for
damages.

In making examinations of suspected food, the samples should
be brought to the laboratory without delay to lessen the change of
other germs gaining entrance. The germs present on the inside
of the material are probably the cause, and cultures are prepared
according to the well-known plate methods. Some of the plates
are incubated in the anaerobic, and others in the ordinary way, so
that all the bacteria present may come under the eye of the analyst.
There is hardly ever enough of the suspected food to make a chemi-
cal test for a ptomaine or toxin, because it is impossible to extract
the minute quantities of these powerful poisons except from large
quantities of material. If any appreciable amount of poison of
bacterial origin could be isolated from a small quantity of material,
it would be so powerful as to kill in a short time all the affected
persons. One gram of tetanotoxin is calculated to be sufficient to
kill 4,500 people.

After the germs have been isolated, those of poisonous char-!
acter are easily identified, and each species is then tested on such
animals as mice, rats, kittens, puppies, rabbits and guinea-pigs by
feeding, by subcutaneous, inoculation, by ultra-peritoneal inocula-
tion and by intravenous inoculation. Various animals are so
treated, because some may not be susceptible. The inoculating fluid
is generally a bouillon culture of the germs, twenty-four hours old,
and the amount used is from one to ten cubic centimeters. Some-
times the inoculation is made with the filtrate of a bouillon culture,
from which all living germs are held back by filtering through por-
celain. After making these tests the analysis for the ptomaines
and toxins are conducted as follows :

Only absolutely pure chemicals can successfully be employed
in this work and this must be ascertained beforehand by evaporat-
ing the ether used and analyzing the residue for poisonous bodies.

The Stas-Otto Method. (Vaughan and Novy.) .

This method depends upon the following facts : ( I ) The salts
of the alkaloids are soluble in water and alcohol and generally in-
soluble in ether, and (2) the free alkaloids are soluble in ether and

206 CANNING AND PRESERVING OF FOOD PRODUCTS.

'are removed from alkaline fluids by agitation with ether. These
principles are capable of great variations in their application. The
usual directions are as follows : Treat the mass under examination
with about twice its weight of 90 per cent alcohol, and from ten
to thirty grains. of tartaric or oxalic acid; digest the whole for some
time at about I58F. and filter. Evaporate the filtrate at a tem-
perature not exceeding 95 F., either in a strong current of air or
in vacuo over sulphuric acid. Take up the residue with absolute
alcohol, filter, and again evaporate at a low temperature. Dissolve
this residue in water, render alkaline with sodium carbonate, and
agitate with ether. After separation remove ether with a pipette, or
by means of a separator, and allow it to evaporate spontaneously.
The residue may be further purified by redissolving in water and
again extracting with ether. Chloroform, amylic alcohol and ben-
zene are used as solvents after extraction with ether.

Brieger's Method. The substance under examination is di-
vided as fine as possible, and then heated with water slightly acidi-
fied with hydrochloric acid. During the heating care must be taken
that the feebly acid reaction is maintained and the heat should con-
tinue for only a few minutes. The liquid is then filtered and con-
centrated, at first on a plate, and then on the water-bath, to a syrup.
An extraction of the syrup is made with 96 per cent, alcohol and
the filtered extract is treated with a warm alcoholic solution of lead
acetate. The lead precipitate is removed by filtration, the filtrate
evaporated to a syrup and again extracted with 96 per cent alcohol.
The alcohol is driven off; the residue taken up with water; traces
of lead removed with hydrogen sulphid; and the filtrate acidified
with hydrochloric acid, evaporated to a syrup, which is extracted
with alcohol, and the filtrate precipitated with an alcoholic solution
of mercuric chlorid. The mercury precipitate is boiled with water,
and on account of the differences in solubility of the double com-
pounds with mercury, one ptomaine may be separated from others
at this stage of the process.

The mercury filtrate is freed from mercury, evaporated, and
the excess of hydrochloric acid carefully neutralized with soda (the
reaction is kept feebly acid) ; then it is again taken up with alcohol
to free it from inorganic salts. The alcohol is evaporated, the resi-
due taken up with water, the remaining traces of hydrochloric acid
neutralized with soda, the whole acidified with nitric acid and treated
with phosphomolybdic acid. The phosphomolybdate double com-
pound is separated by filtration and decomposed with neutral ace-
tate of lead. This is hastened by heating on the water bath. The
lead is removed by hydrogen sulphid, the filtrate is evaporated to a
syrup and taken up with alcohol, from which many ptomaines are
deposited as chlorids, or double salts may be formed in the alcoholic
solution.

DECOMPOSITION CAUSED BY MICRO-ORGANISMS. 207

The chlorids deposited from the alcoholic solution are seldom
pure and may be isolated by precipitation with gold chlorid, plat-
inum chlorid, or picric acid, and on account of the differences in
solubility of these salts, the purification is rendered more easy.
The chlorid of the base is obtained by removing the metal with
hydrogen sulphid, while the picrate is taken up with water, acidified
with hydrochloric acid, and repeatedly extracted with ether, in order
to remove the picric acid.

These remarkable methods are not the only ones used in ex-
tracting bacterial poisons, but they are sufficiently complicated to
test the skill of even first-class chemists and may be used as a means
of defense against falsely reported discoveries of ptomaines in food
products.

We will conclude this subject by naming some of the poisonous
ptomaines which have been isolated by some of the most eminent
chemists in the world. (Tetanotoxin CgH^N) (Amylanim C 5
H 13 N) -Hexylamin C 6 H 15 N) Trimethylenediamm C 3 H 8 N 2 )-
(Susotoxin C 10 H 26 N 9 ). (Methyl guanidin C 2 H 7 N 3 ) (Asellin
C 25 H 32 N 4 )-(NeurhT C 5 H 18 NO) (Cholin C 5 H 15 NO 2 ) G (My-
datoxin C 6 H 13 NO 2 ) (Mytilotoxin C 5 H 15 NO 2 ) (Gadinin C~H 1T
NO 2 ) (Typhotoxin C 7 H 17 NO 2 ) (Muscarin C 5 H 15 NO 3 ) (Te-
tanin C 13 H 30 N 2 O 4 ). (Tyrotoxicon, Mydalein, Spasmotoxin,
Adiamin, Peptotoxin and many others unnamed.)

208 CANNING AND PRESERVING OF FOOD PRODUCTS.

CHAPTER VI.
Sterilization

Nature of Spores. Cleanliness in Manufacturing 1 . Disposition of
Waste Material. The Venting Process. Vacuum Machinery.
Discontinuous Sterilization. Preservatives Formed in Sterili-
zation.

STERILIZATION.

Its Application in Canning and Preserving

To sterilize any material is to make it barren, or to destroy the
bacteria present, or render them incapable of reproduction. In
its broad meaning, it might embrace the use of any chemical or phys-
ical force, capable of destroying reproductive powers, but in its re-
' stricted sense it means to apply heat to destroy micro-organisms
or to hinder their vegetating power.

The large number of bacteria which do not produce spores
are easily destroyed at temperatures ranging from 140 to 180 de-
grees F., moist heat, and to this class belong nearly all pathogenic,
lactic and acetic bacteria, and also yeast and molds, although these
are more resistant to heat than the bacteria mentioned. To the
other class which produce spores belong the butyric, subtilis and
mesenteric families, and a few to the Pathogenic. There are a
great number of species belonging to these families, some of which
produce spores of great vitality, and these spores are able to resist
boiling for hours, owing to a thick membrane which protects the vi-
tal power within. They resemble dry beans, peas, corn, etc., and
the older they are, the closer do their heat-resisting membranes
enclose their life. I have seen beans so hard after several years
drying, that they refused to absorb water for two* weeks and then
very slowly, so when spores become old it is reasonable to suppose
that they shrink, and the pores of their membranes become im-
pervious to moisture, so that they require very high temperature
to deprive them of vitality. So small do these spores become, that
even the microscope fails often to reveal their presence in fluids,
and one writer has conceived the idea that they might not become
wet, if air containing them should be forced through sulphuric acid.
This might seem ridiculous on first thought, but when we consider
their minuteness and the repellant force of certain substances
against moisture, it does not seem so unreasonable. If we fill a

STERILIZATION. 209

glass graduate with water, so that the surface is not disturbed,
there will be a distinct difference between the height of the water
at the center from that at the edge of the glass ; the glass holds the
rising fluid down below the service level, unless it be first moist-
ened. A thin cover-glass will float on a fluid, although its specific
gravity is much greater; the repellant force will bank up the fluid
all around it, so that it will float below the surrounding surface of
the fluid, which has no power to wet the upper surface of the glass.
The same phenomenon may be observed if a small needle be gently
laid on the surface of the fluid. To my mind it seems reasonable
to suppose that some spores are so constructed that they will repel
the surrounding fluid and do* not become wet until certain changes
are produced in that fluid, either by increased temperature or
nutritive power, or by chemicals which may attack the cell mem-
brane.

For general sterilizing purposes, the packers of hermetically
sealed goods use moist heat. This kind of heat is far better than
dry heat, because of the character of the cell membrane of bacteria ;
and spores. It is by the absoqDtion of moisture that bacteria are
able to grow and vegetate, and their spores are enabled to send
forth young rods. Steam heat therefore exerts a violent action
against life and destroys it much quicker than the same tempera-
ture of dry heat. The action of the cell membrane against dry heat
might be likened to that of asbestos. For sterilizing canned goods,
the packers use several devices which are all good, but the thermal
death point of the bacteria present in the cans is a problem.

There are a number of bacteria closely resembling one another,
which produce spores greatly varying in heat-resisting power; the
most resistant species known was discovered by Globig, which is
found on potatoes, and is called the "Potato bacillus." This or-
ganism produces spores able to live through six to ten hours
or more of boiling temperature. Almost all the bacteria having
great heat-resisting power are found in cultivated soil, and are
present on the stems, leaves and edible portions of all vegetables.
If the juices of these plants become infested with spores of these
various species, the problem of sterilization is a deep one ; too much
heat destroys the flavor of the canned product, and as a rule cannot
be fixed broad enough to take in the thermal death point of all heat-
resisting germs, since nearly all speices are able to grow on most
of the vegetables used for canning, excepting tomatoes ; for instance,
the juice of peas nlay be used to cultivate in pure culture the "Potato
bacillus," and we all know that a process sufficientlv high to destroy
the spores of this microbe would cook the peas to pieces and destroy
the flavor. When decomposition of vegetables sets in, especially while
yet in .the field, or when they are piled up with the pods, leaves or

210 CANNING AND PRESERVING OF FOOD PRODUCTS.

vines still present among them, the way is made easy for the devel-
opment of numerous spore-bearing bacteria, which find a suitable
nutritive material in the exposed juices, to multiply and produce
spores. When cultures are made of the bacteria found on the stems,
leaves, pods or husks, the varieties of spore-bearing bacteria found
are numerous. As we have stated before, the most hardy bacteria
are found in the. soil, and they are growing rapidly on all dead
matter which nature carries down to them ; their spores are formed
and under the warm summer sunshine they become dry and light,
and are carried by currents of air to all parts of the field, rinding lodg-
ment on the growing plants, they lie dormant until they gain entrance
to nutrient juices, when they begin a new life cycle and form the
same hardy spores which are often found in cans of spoiled goods.

Now, to make the point clear, if packers use raw material which
is bruised or partially decomposed, they have much to contend with,
because they must process this material long enough to destroy all
manner of bacteria, which gain entrance to the deep portions.

The value of a blanching bath for peas, string beans, asparagus,
etc., is twofold; it arrests decomposition and it washes away many
resistant forms of germs, but if the deepest tissues and fibres are
penetrated, the washing does not carry away the destroying agents.

There are some points worthy of consideration here, and we
refer to the nature of certain vegetables, and their nutritive value
for various bacteria. Every kind of fruit and vegetable has a chem-
ical composition peculiar to itself; some are strongly acid, while
others are nearly neutral, some have considerable starch and al-
bumen, while others are rich in sugar or carbohydrates ; some have
antiseptic compounds, such as benzoic acid, phenol, salicylic acid,
creosote, formaldehyde, etc., but the amount is only small, yet suffi-
cient to prevent the growth of many species of bacteria. There
are certain species of bacteria which are always found associated
with a given kind of vegetable or fruit, which furnish the germs
with all their vital requirement; other species may be present, but
are checked in their growth by the greater multiplication of the reg-
ular species. Certain bacteria peculiar to peas may be able to force
entrance to the juices, while others would find nutrition only on ex-
posed surfaces. This accounts for prevalence of certain species
on a particular^ kind of vegetable.

The processor becomes familiar with a certain temperature,
prolonged for a given time, which seems to sterilize the same veg-
etables, fruits, etc., year after year, without very much spoilage,
but suddenly the old rule fails and whole batches of canned goods
spoil because of a new species of bacteria having taken the field;
the old process is not sufficient to destroy the spores of the new
variety. How necessary it is to know the reason for this ! Only
a knowledge of bacteria can help him.

STERILIZATION.

211

Plate 68. Globig's Potato Bacillus, Flagellated

Photomicrograph of Globig's Potato bacillus, showing numerous flagella. Magnified 1,200 diameters.

Plate 69. Globig's Potato Bacillus

Photomicrograph showiug Numerous Spores which are larger than the Rods in Diameter. Culture from
Agar, isolated from Spoiled Corn. Stained with Fuchsin. Slide preparation by Author. Magnified X 1,000.

STERILIZATION. 213

There are some natural causes for the presence of new vari-
eties of bacteria which suddenly make their appearance in canned
goods. The^veather often has an influence on the chemical com-
position of raw material; during some seasons there may be more
sugar and less starch, or there may be less sugar and increased
acidity, due to rains or drought. We have all noticed that it is
sometimes the very finest looking corn which spoils. We have seen
tomatoes crack open by sunshine after rains, and later have heard
the popping of the corks from the catsup bottles, or seen the cans
swell in various piles.

The nature of the soil may ha re an influence. The farmers
have been growing for us the same products year after year in
ground cared for and manured regularly; suddenly it becomes nec-
essary to procure a certain fertilizer and a number go in together
and buy fertilizer which changes the chemical composition of the
truck raised on the ground.

Now when changes take place in the chemical composition of
raw material, it may not be just suited to the same varieties of bac-
teria formerly found associated with it, but the changed constit-
uents form the nutritive elements necessary for the luxuriant growth
of more formidable species.

The problem of sterilization becomes a scientific study, when
such changes as we have mentioned take place in the composition
of the raw material. To be sure, anyone may be able to sterilize
any kind of product by giving it a high temperature for a long time,
more than is actually necessary; but to know just how much is suffi-
cient, and to be sure that the goods will keep well, is where good
judgment is required. If the packers would supply themselves
with a good microscope, with one-twelfth oil immersion ob-
jective and an incubator, it would be a verv easy matter to
know positively if a given process was sufficient. A can or
a number of cans from each day's work could be placed in the incu-
bator, and if the sterilization was not complete the bacteria would
develop at a blood temperature within twenty-four to forty-eight
hours; juice from these cans could be made into a hanging drop,
and if any bacteria happen to be present, the microscope would re-
veal them. Most of the spore-bearing bacteria are motile, and
there would be some present, even in small quantities of the juice,
long before the formation of sufficient gas to swell the cans. A
number of tests could be made with juice of these cans, and the
packer could keep close watch on the sterilizing process, and in
many cases could reduce the time, which would insure a better
flavor.

The exhaust process, or the filling of cans with hot material,
prior to the final process, is a good plan for two reasons : The hot

214 CANNING AND PRESERVING OF FOOD PRODUCTS.

material is expanded by the heat, which produces a vacuum after
the cans are sterilized ; the heat thus given the material will shorten
the final process. The temperature given in the final process varies
according to the material and size of the cans. A thermal death
point for the bacteria present is first determined, then, to this must
be added the time required for that heat to reach thfe center of the
cans; for this purpose the manufacturers of thermometers have
made a device, with a self-registering thermometer to indicate the
temperature at the center of the can; by repeated experiments the
time required for penetration may be known. The mercury tube
has a constriction which prevents the return of the metal to the
bulb, and when it is removed will show the exact maximum heat
at the center of the can. These-little devices are inexpensive and
should be used by every packer.

We have referred to the vacuum produced by the exhaust pro-
cess, or filling of cans with hot material prior to the final or steril-
izing process ; the vacuum is convenient for drawing the tin back
to normal shape after it has been swelled at both ends in the ster-
ilization. There was a strong belief among packers that a vac-
uum was absolutely necessary for preserving canned goods, and
there still exists a belief of this kind, not only among some packers,
but machinery men as well. The vacuum has no value as a means
ofjpreventing decomposition by bacteria. Even if a very power-
ful vacuum could be produced, it would not prevent the hardy spore-
bearing bacteria from developing in cans under-processed. Even
if the oxygen remaining in the partial vacuum could be replaced by
hydrogen or carbonic acid gas, these bacteria would still be able to
grow and multiply. Nearly all of the species identified with spoil-
age of canned goods grow well in the presence or absence of oxy-
sgen, and though aerobes, generally are also facultative anaerobes.

The temperature and time required for sterilization, depends
upon the nature of the bacteria present, and the character of the
material. Different fruits ami vegetables vary in their chemical
composition. There are also {narked differences in the same vege-
tables and fruits grown in different parts of the world. Tomatoes
grown in the Northern States, Michigan, Wisconsin and Minne-
sota, have less acid and more sugar than those grown in Iowa, In-
diana, New Jersey, and Delaware. The different varieties of fruits
and vegetables vary in their composition, so that the conditions are
different in one locality from those in another. Even in the same
locality two kinds of peas or corn, etc.. may require different steril-
izing processes, owing to the presence on one of a particularly
hardy spore bearing baccillus, which may not be growing on the
other variety.

STERILIZATION. 215

It is not possible, therefore, to make a bacteriological investiga-
tion of spoilage in one locality and make the conclusions fit the
conditions in all cases. One or two bacteriologists have made care-
ful study of sour corn, and isolated a number of bacteria found in
the cans, but these bacteria are not always in sour corn; some of
them may be found, and even other species entirely different in an-
other location. The same thing applies to peas, beans, asparagus,
tomatoes and all kinds of fruits, but these fruits do not vary so
much in all their germ flora as do vegetables.

The difference of time and temperature required for sterilizing
different kinds of vegetables has been a perplexing problem for
canners. It is not generally understood why peas should keep
at a temperature below that of corn fully twenty minutes less in
time, or why peaches should keep when processed several minutes
less than tomatoes.

The difference is due to two facts there are different species
of micro-organisms and there are chemical differences in composi-
tion which render the juice of one antiseptic to germs found in the
juice of another. As a rule bacteria do not grow in juices which
have a marked acid reaction, although there are notable exceptions
to this, but generally speaking the more acid the juice contains, the
fewer the species of bacteria. The hardy spore bearing bacteria,
as a rule, do not thrive well- on acid media, even small quantities
being detrimental to their growth. The slight addition of sugar
however, overcomes the antiseptic properties of some juices, and
the spore-bearing bacilli are able to grow to some extent. The
writer has often been surprised on opening cans of under processed
goods, which were bulged at both ends from the enormous pressure
of gases within, to find how few bacteria the juices actually con-
tained. The spores had developed and some reproduction had re-
sulted, until the amount of acid formed had acted as an antiseptic,
and multiplication had apparently ceased.

It often happens that the can springs a leak from the pressure,
and the gas is liberated, then the bacteria from the air gain entrance
and the acids are attacked and reduced to fatty or volatile acids, the
original agents having gone into a resting state, or formed spores.

The climatic conditions of certain localities have something to
do with the varieties of bacteria found associated with spoilage. In
some of the Central and Southern States there are much hardier
varieties prevalent than in Northern States, or the New England
States, consequently a process that is giving satisfaction in Maine
may not be sufficient for sterilizing the same product in Ohio.

Cleanliness^ and proper disposition of waste material, are prom-
inent factors in sterilization. There are times during the canning-
season when the raw products, or material only partially cooked,

216 CANNING AND PRESERVING OF FOOD PRODUCTS.

are exposed to the ravages of bacteria floating- on dust, and matter
held in suspension by the atmosphere. This is the case when break-
downs occur in the machinery, or when the work is not carried on
systematically, or when the receipts of raw material are greater than
the canning capacity. The danger is greatest where partially
cooked material is exposed to the air. The spore bearing bacteria
and the putritive anaerobes are liable to set up unperceived decompo-
sition, and elaborate foul substances such as indol and skatol, or
may produce bitterness or disagreeable acidity. The partially
cooked material offers a more suitable nutrition for these true sca-
vengers, because die cellulose or fibre is softened and the juices are
richer in albuminous compounds, which furnish them with all their
vital requirements. The danger from these bacteria is not so great
where absolute cleanliness is exercised and proper disposition is
made of waste material. If the waste material such as cobs, hulls,
husks, vines, stems, peelings, seeds and trimmings, are dumped in
heaps in the vicinity, the air will be found teeming with the spores
of these micro-organisms, ever ready to fall into nutrient material,
and there begin their work assigned by nature, the tearing down
process of fermentation or putrefaction. If accumulations are al-
lowed to stand from one year to another, the spores of these bac-
teria may become so dry and hard that the old and tried sterilizing
process will fail to be effective. There is great truth in these state-
| ments, viz., that age will toughen the spore membrane and that the
spore protoplasm will dry and shrink and be more impervious to the
action of heat, and require longer time to absorb moisture so nec-
essary for rapid sterilization. Thus the ordinary sterilizing pro-
cess becomes ineffective. The same danger may lurk in the dirt and
dust of the factory; if the floors and machines are not kept clean,
by the liberal use of soap, hot water and steam, the harmful bacteria
will be present in all parts of the building, in such numbers as to
produce chemical changes where least suspected. The evil of un-
cleanliness is not confined to the breeding of bacteria alone, but flies,
insects, rats, mice, etc., are drawn by the opportunities of getting
food, and the whole factory will soon be in a very bad condition.

How is it possible to produce fine goods where the entire es-
tablishment gives the impression of careless, neglectful methods!
Unclean methods breed carelessness in employees, and this becomes
evident in the character and quality of the goods turned out. The
sterilization is accomplished only at a time and temperature beyond
that actually required in a clean, well-regulated factory, and the
product has lost the color and flavor which we might suppose once
existed.

\Vhen Isaac Winslow began to pack corn in tin cans, he used
only an open batli process at first. . He boiled the cans for several

STERILIZATION. 217

hours and succeeded, strange to say, in keeping a large per cent, of
his goods. Our readers are familiar with the history of his after
failures, and his final adoption of the steam retort. That he was
ever able to sterilize corn by simply boiling the cans has been a
source of wonder to the writer; certainly none of the well-known
heat resisting bacteria were present, or if so they had not become ac-
customed to corn. This theory seems to have some foundation, be-
cause bacteria are known to accommodate themselves to certain ma-
terial when forced to grow in it; for instance, the Bacillus Diph-
theria grows very scantily upon ordinary agar, when planted fresh
from the false membrane of a diphtheria patient, yet after trans-
planting upon the same medium a number of times, it grows quite
well and if kept in a cool place, loses its virulence to a certain extent.
The Typhoid Bacillus becomes less virulent after repeated trans-
planting, and the same characteristic has been demonstrated in
various species. So it may be when corn was first grown in this
country that the hardy spore bearing bacteria did not at first find
suitable nourishment, except in some cases. Now it is fair to pre-
sume that when once started the bacilli became accustomed to corn,
and their nature having changed through that nourishment their
spores more easily attacked the corn in following years. The open
bath process suddenly failed and Winslow and his contemporaries
lost almost their entire pack.

It is well remembered that corn w r as sterilized a few years
ago by a certain process which is not now effective in all cases, so w r e
cannot but hold to the theory that the most hardy species of bacteria
are gradually becoming accustomed to corn, and perhaps other vege-
tables. Xo one can say that new r species are being created, but
such may be the case; if so, then we may be able to' explain the
necessitated increase of temperature for sterilization. There are,
however (found on vegetables), so many species closely resembling
each other, differing only in one or two characteristics, that we are
strengthened in our first theory, and we may ascribe those differ-
ences to the changes in the materials upon wh ; .ch they have habit-
uated themselves.

By increased temperature in the sterilizing process, certainly
the color and flavor suffered to some extent, the color particularly,
and the demand made by the trade for nearly natural colors in
canned goods, forced evil practices upon the packers, corn was
bleached and peas were colored with copper, and tomatoes received
the "sunshine" from aniline dyes. In some cases the sterilization
was reduced, and antiseptics added. This helped to preserve the
color, but the quality suffered even more than by increased tempera-
ture. In the course of time these methods passed the limit, and
some of the goods put upon the market were unsightly, and the

218

CANNING AND PRESERVING OF FOOD PRODUCTS.

flavor was completely lost. Tomatoes and catsup were colored
beautiful carmines, and looked more like red paints than articles of
food.

By the excessive use of chemicals and colors to shorten the
sterilization, the public turned away from canned goods of this na-
ture, and it is well remembered how the prices dropped to almost
nothing (several years ago). The people were getting liberal
doses of all kinds of chemicals and colors, in nearly every manu-

Fig. 31

factured food product brought to the table, so they clamored for
pure food laws, elected State Food Commissioners, aided by skilled
chemists, and the tide has turned the other way. There is no
doubt that these abuses will have settled the lawful right to use cer-
tain colors and preservatives, there may be some condiments ex-
cepted, but certainly none will be permitted in canned goods, nor
are they necessary.

STERILIZATION. 219

The apparatus for sterilizing canned goods is simple, consist-
ing of retorts with lids which may be sealed; into these live steam
is conducted and used either dry or with water and the retorts are
exhausted to keep up the circulation, while the temperature is main-
tained by a thermometer and steam gauge.

For all vegetables, meats, soups and foods of albuminous na-
ture, which furnish all the elements of nutrition for spore bearing
bacteria, a temperature of 250 F. is better than any lower degree,
f ( >r the reason that spores perish at that degree of heat quickly ; the
time required is variable owing to the numerous complications we
have described, viz., the various species of bacteria to be destroyed,
the character of the material, and its heat penetrability. Our ex-
perience leads us to believe that dry live steam is more reliable
than water, because circulation is more thorough, but there is al-
ways some danger of discoloration, which may be avoided as fol-
lows. A water connection is made with the water line by means of
steam hose, to the lid of the retort, and a large overflow is made near
the top of retort, so that a considerable volume of water may be let
into it. just as the temperature drops to about 220 F. after the
cans have received a full process. The sudden rush of cold water
chills the goods, and stops the cooking which is still going on within
the cans. Otherwise when the cans are thus cooking, and the lid is
opened suddenly, the air striking the cans will cause discoloration,
but if the retort is completely filled with cold water (before opening
the lid), the color will remain good, and there will be no scorched
taste unless the sterilization has been unnecessarily prolonged.
250 F. is equal to about fifteen pounds pressure and may weaken
the seams of the cans unless the chilling is done (with water) before
their exposure to the atmospheric influences.

Another method of sterilization coming into favor is the cal-
cium process, which in some measure seems like a return to ancient
methods, yet improved as it is, has some advantage over the ordin-
ary steam retort system. The principle of obtaining a higher de-
gree of heat than boiling water in a fluid, is based on the specific
gravit^ ^ the fluid. By adding calcium to water the specific
gravity is increased until temperatures of 240 and even 250 F.
may be obtained, without ebullition, consequently there is little or
no escaping steam, and the temperature may be maintained at a
very small expense, when compared to the cost of generating steam
for retorts.

The latest device consists of a long tank filled to a certain depth
with calcium water, through which the crates containing the cans
are dragged on a carrier, which is slowly speeded to give the re-
quired time for sterilization. After the cans are sterilized, they are
carried through running water to cleanse them, and this also stops

220 CANNING AND PRESERVING OF FOOD PRODUCTS.

the cooking which is going on inside the cans after they have passed
through the calcium bath. This process has the advantages men-
tioned above, being a fuel and labor-saving method, but it cannot
be used successfully for sterilizing glass goods, which require high
temperatures. Glass goods are difficult to sterilize, owing to the
breakage and the small expansive properties of glass. Glass goods
of all kinds may be sterilized with dry steam at any temperature up
to 250 F., if the precautions are taken to raise and lower the tem-
perature very slowly. The successful sterilization of glass goods
depends largely upon the quality and thickness of the glass, also the
method of sealing*. The French have been importing all kinds of
fruits and vegetables put up in glass, but nearly all such goods are
preserved with antiseptics of one kind or another, and while they
look well, are not to be compared to the goods packed by many Am-
erican canncrs. Glass seems to have the advantage over tin, in the
opinion of many persons, because there is a mistaken and widespread
belief that there is some danger of metallic poisoning from tin
and the solder and flux used in sealing. It is a question, however,
if there be more metal in tin goods than in some of the highly-
colored French glass goods sold on the market.

The writer has made a number of analyses of various canned
goods for tin, lead and zinc, and the quantity of the first two are
almost incalculably small. The most definite amount of tin and
lead were obtained from canned pineapple and California fruits, but
no appreciable amount was obtained from these. Some samples
showed the presence of more or less zinc, due to careless use of
soldering solution. The old method of brushing the caps with an
ordinary paste brush dipped in zinc chlorid has given way to the
beautiful little machines which carry the solution on pencil brushes
around the crease of each can, allowing none to be sucked in through
the vent hole.

Of course, glass goods, if packed with care and without the use
of preserving agents and metallic colors, are entirely free from
metals, excepting where they are found in composition. Some
vegetables have iron and copper in composition. Tomatoes grown
in Western Pennsylvania contain some copper.

The sterilization of goods in glass imparts a slightly scorched
taste, because it is impossible to chill with water. The cooking
goes on until the temperature drops below the boiling point.

Another method of sterilizing canned goods has found favor
among the packers of canned meats and special food products. The
apparatus is a monstrous affair requiring a great deal of room.
The cans are placed in the carriers and allowed to pass through
oil. which is heated to a certain temperature. This apparatus is
used by the Armour Packing Co. of Chicago, and the results are

STERILIZATION. 221

very satisfactory. After the cans pass through the oil, they are
drained and then carried through an alkaline solution, and then
through running water.

There are several methods employed now to avoid the old
"venting" process and even in the canning of meats this is entirely
obviated. The object of the venting process was two-fold, viz., to
heat the contents of the can to obtain a vacuum, and to drive off
unpleasant gases. Outside of tomatoes, there are hardly any pro-
ducts cold packed unless special apparatus is employed. For or-
dinary canning all that is necessary is to heat the syrup or liquid
which is used to cover the fruits and vegetables, or to heat the vege-
tables before filling into the cans; corn is thus heated before the
filling.

There are several devices used to pack certain goods without
previous heating or "venting" ; all these are modifications of- the
vacuum process. The cans are passed into a machine which ex-
hausts the air by a vacuum pump, and while in vacuo are sealed.
The machine used in packing meats is interesting, because the "tip-
ping" or "dotting" is done in vacuo. The machine is round and
carries the cans in 15 pounds vacuum, under a glass window; the
inside is illuminated by incandescent light, and a small round disc of
solder is melted by a copper, which is heated by electricity. The
operator can look clown through the window and melt the solder
over each hole as the cans pass ; when all have been "tipped," the
vacuum is released and the cans pass out, when they are inspected
for leaks.

The old method of venting canned meats was difficult, costly
and uncleanly. The cans were filled cold, and a piece of tin was
bent and soldered onto the under side of each cap to prevent the
meat from coming up into the hole, which was made with an awl
after the cans were heated the first time. The juice and' grease
would squirt all over everything when the cans were punctured and
the closing of the holes was quite difficult, requiring skilled help.

There are several kinds of vacuum machines on the market,,
but they require special cans. The lids of these cans are prepared
with patent cement. The cans are put into the vacuum machine
with the lids loosely placed, and when the air is exhausted the lids
are forced down into place and the cement holds the vacuum in the
cans. The cans are made without soldering, except the body seam,
the sealing being completed by crimping the flanges of the body
together with the rims of both tops and bottoms. The cement com-
ing between the two edges prevents leakage.

These machines are used in European canneries and give good
satisfaction. Recently, improved machines have been built in Am-
erica for making these cans. These cans are also coated with a

222 CANNING AND PRESERVING OF FOOD PRODUCTS.

substance which is not attacked by fruit acids. The inside coated
cans are preferable for goods of delicate color. The ordinary cans
are thus coated also.

There is another method of sterilization used largely in bac-
teriological work to destroy the bacteria in culture media, which
become altered by high temperatures. It is called "Discontinuous
Sterilization" and was discovered by Prof. Tyndall during his ex-
periments and efforts to overthrow the theory of "spontaneous
generation," advanced by Von Liebig and his contemporaries.

Prof. Tyndall experimented with all kinds of infusions made
from meats, vegetables and grains, trying various degrees of heat
from 212 to 300 P., and prolonging the time for hours. These
experiments are recorded in Tyndall's "Floating Matter of the Air."
There is no question but that his experiments at 300 F. were faulty
wherever he failed to sterilize his infusions in an oil bath. We have
conducted numerous experiments, using various temperatures, and
up to this time have never discovered any species of bacteria whose
spores could withstand 250 F. moist heat for more than a few
minutes. This statement must not be applied to the sterilization of
canned goods, nor any material which is impervious to heat ; it ap-
plies only to that temperature directly upon the spores, which are in
solutions or materials easily penetrated by heat.

Tyndall's infusions were sterilized in glass flasks having a thin
tube for escaping steam, which w-as sealed by melting the glass to-
gether while the steam was escaping. This would not be reliable,
since the temperature must be lowered to melt the glass together,
or else there would be a fine hole in the glass, which would be an en-
trance for bacteria from the air. If the infusions were cooled to
allow the perfect sealing of the glass, a vacuum would form in the
interval and spores from the air could find entrance.

There is no question but that 250 F. moist heat for twenty
minutes will destroy all known spores, if the necessary precau-
tions are taken to avoid contamination from the air. It is mar-
velous how a small hole in the soldering of a can will be the means
of spoiling the contents. Holes which are as small as a needle
point, are wide open doors for such infinitely small vital powers as
spores, and it is often difficult to find some of these leaks in spoiled
cans. Through a hole the size of a period (.) 50,000 spores could
pass side by side into a can without touching the metal.

Discontinuous sterilization is conducted as follows : Moist
heat, usually 212 F., is applied to the material in water bath, for
a time ranging from twenty minutes to one hour, after which it is
placed in a cool place for one day, and the same process is then ap-
plied a second time, and this is continued for three days, so that
the material receives four processes, which render it sterile.

STERILIZATION. 223

The scientific principle is based on the time required for spores
to vegetate. As we have stated in previous pages, the vegetating
cells are easily destroyed; very few, indeed, are able to withstand
180 F., and almost all perish at 165 F. Xow the spores, being
very resistant to heat, are simply softened during the first one or
two processes, and readily perish when they begin to vegetate.
Probably most of them are destroyed in two heating, but a few of
the drier forms may require a day or two longer to swell up and
vegetate, so that the four heatings will as a rule destroy all.

As we have stated, there are certain materials which are chem-
ically altered by high temperatures, and it is necessary to resort to
the discontinuous method in order to prevent undesirable changes.
Gelatin loses its solidifying properties if heated to 230 F. Milk
is very much altered when heated even to boiling temperature, there
being formed such substances as formaldehyde, dioxygen and cal-
cium citrate, the latter being thrown down as a precipitate. Milk
is therefore sterilized at about 165 F. for one hour, on five consecu-
tive days, to avoid these alterations.

There are constantly made improvements on all methods of
work and we believe that the discontinuous sterilization of canned
goods by practical means offers a good field for experiment and
study. On a small scale in laboratory work it is successful. All
kinds of infusions of meats and vegetables are easily sterilized (in
test tubes and flasks) by simply plugging the necks with cotton and
heating in the manner just described. The color and flavor of such
vegetables as corn, peas, string beans, asparagus, cauliflower, lima
beans, etc. (when sterilized discontinuously), are very much su-
perior to those of the regular canned goods, which have received
240 or 250 F. The writer has made a number of such experi-
ments and the results are gratifying.

Sterilization by electricity, such as a direct current or an al-
ternating current or the X-rays is not reliable, and by the first two
certain chemical changes are produced which are undesirable. It
was hoped and claimed that the X-rays would accomplish steriliza-
tion by causing paralysis of the bacterial cells, but repeated experi-
ments have demonstrated only failures.

Sterilization by heat is the only method of value for the can-
ning industry. There are some special products which are pre-
served by chemicals, but these will no doubt be regulated by pure
food laws in such a manner that only a minimum quantity of pre-
servatives will be permitted, or perhaps none.

One fact must not be lost sight of, however, and that is that
various fruits and vegetables contain within themselves certain
acids and salts which make them easy to sterilize by heat; these ele-
ments of composition act as antiseptics and in some cases as disin-
fectants for many of the spore-bearing species of bacteria.

224 CANNING AND PRESERVING OF FOOD PRODUCTS.

It must not, therefore, be inferred that a certain process by
heat actually destroys all life, but that all bacteria are prevented
from multiplying through the destruction of some (by heat) and
the antiseptic power of the juices. This may hold good so long as
perfect fruits and vegetables are used and the complete elimination
of all foreign matter is observed, but should unsound material be
used or adulterations find favor, or should dirt or foreign matter
get mixed in with good material through carelessness, the condi-
tions w r ill be changed, and the regular heating may not prevent de-
composition. By avoiding adulterations and observing the strictest
rules of cleanliness losses will be minimized.

Certain fruits contain antiseptics, as we have stated, and cer-
tain antiseptic compounds are formed by oxidation of sugars and
fats, by the influence of light and at 250 degrees F. These antisep-
tics play a very important part, as we have shown in sterilization,
and it is our purpose to study the various compounds found in
canned goods, and also the various antiseptics which are used to
accomplish sterilization in special food products.

PRESERVATIVES. 225

CHAPTER VII.
Preservatives

What are Preservatives? Preservatives are not Ordinarily Used
in Canned Goods. Some Food Products Require Them. Nat-
ural Origin of Preservatives in Food Products. Statements
made by Various Authorities Analyzed and Criticised. Sterilized
Catsups, Preserves and Fruit Butters not Satisfactory to the
Trade. Some Opposing Arguments Answered.

It is well known that certain chemicals when added to food
have a restraining influence upon the bacteria, yeasts and molds
which are associated with its decomposition. Some chemicals pre-
vent, the multiplication of bacteria and are called antiseptics, while
others will kill the germs and also the spores and are classed as
disinfectants. It is difficult, however, to draw the line between
antiseptics and disinfectants, for the reason that large quantities of
the chemicals known as antiseptics, may also prove to be germicidal
and therefore disinfectants, and, on the other hand, small quantities
of chemicals known to be germicidal, may not destroy the life of
bacteria and therefore only antiseptic. Some antiseptics when
used in limited quantities favor the growth of certain bacteria and
are used in obtaining pure cultures ; the chemical will prevent the
growth of some varieties which ordinarily overrun the culture plates.
The term antiseptic is applied to a number of chemicals which are
used to some extent in the preparation of foodstuffs, principally
catsups, sauces, preserves, etc. They have been found in canned
goods in some cases, no doubt, purposely added by the packers to
shorten their sterilizing process, but more commonly due to natural
causes.

The harmful nature of the various chemicals has been argued
pro and con by the best exponents of science, but their effect upon
the human body is disputed, and the actual effect of some is not
known. They may be harmful or they may not be. but they are con-
sidered (by the authorities) as unnecessary, and "the burden of
proof, therefore, rests upon those who employ them." If they are
not harmful, then they may be classed as adulterants (if used in
canned goods) from the fact that they are largely unnecessary and
do not add any nutritive value to the food. If they are harmful,
there is sufficient ground for prohibiting their use. There can be
no possible argument for the employment of chemicals as antiseptics
in canned goods;

226 CANNING AND PRESERVING OF FOOD PRODUCTS.

I do not find that they are used to any great extent in canned
goods, the methods of former years having been superseded by the
more reliable and less expensive sterilization by heat only. There
may be some packers who use chemicals for preserving canned
goods, but they are very ignorant of their business. The best
houses sterilize all canned goods by steam heat either directly or in-
directly, and do not increase the cost by adding expensive antisep-
tics.

Some of the published reports of antiseptics found in various
brands of canned goods are absurd and misleading. There have
appeared reports indicating that as many as three different chemi-
cals were found in a single can. On the face of it, it is most unlikely,
because no packer would be so foolish as to waste his money in this
manner, and even if he should use the chemical method he would
hardly use more than one as an antiseptic.

Antiseptics have been too freely used in some kinds of food in
the past and adulterants have been added to so many varieties of
food that the public has rebelled and food commissioners have been
employed to fix the responsibility upon guilty manufacturers and
laws have been passed to prevent such products from being exposed
for sale. Some of the reports made by analytical chemists will
show to what extent this has been practiced, and while they may be
overdrawn in cases, yet there is no doubt that such practices have
gone beyond the limit of tolerance.

It was claimed by one very radical food commissioner that it
was no uncommon occurrence for a person to sit down .to a meal
having the following list of chemicals included in his diet : "Ham
containing saltpeter ; canned corn containing saccharin, salicylic acid
and hyposulphite of soda ; canned peas containing copper and alum ;
tomato catsup containing benzoate of sodium and coal tar dye;
wheat cakes containing ammonia or alum ; maple syrup made from
cane sugar syrup and glucose ; mustard containing tumeric ; milk
containing formaldehyde; coffee artificially prepared from various
substances; pepper containing ground cocoanut shell, and butter
containing borax. Verily one would have an internal drug house
if this were continued day after day." It is hardly likely that a
person would be so unfortunate as to meet with all these compounds
in a single meal, yet it might happen that he would be confronted by
a few of them at least. The claim is made that such combinations
must in time cause trouble in the human stomach, because the juices
which enter into the digestive processes were never intended to per-
form the work of an analytical chemist three times each day. If
such conditions actually existed there would be some ground for
complaint, but canned goods packers are not responsible for these
adulterations. There are some points worthy of consideration

PRESERVATIVES. 227

when dealing with the question as to whether antiseptics shall be
prohibited in all food products. It is well known that bacteria are
scavengers and more readily attack food which has been cooked,
than food in the raw state ; the cooking seems to soften those foods
containing fibre and releases the nutrient juices and fluids upon
which the bacteria find suitable elements for growth. Bacteria
which produce ptomaines and toxins and disease parasites also flour-
ish upon cooked food, and if that food is not consumed as soon as
it is exposed, it may prove more dangerous than if it contained an
antiseptic. There are many food products which are not eaten
alone, but are used to give flavor and relish to other articles of pre-
pared food. Such products may not be entirely consumed at a sin-
gle meal and may be regarded as luxuries. Now, if any of this
class is subject to decomposition it would seem wise to use a certain
per cent of antiseptic to preserve it. Under this head might be '
mentioned such articles of food as butter, cheese, tomato catsup,
Chili-sauce, apple-butter, peach-butter, and other sauces and relishes.
The argument has been advanced that such foods may be prepared
in small size packages, and thus avoid the necessity of carrying
over from one meal to another, but the expense would be heavy, and
in many cases would not be practical, especially for hotels and res-
taurants. This is a question worthy of careful consideration and
we believe that the manufacturer has a shade the better of the argu-
ment.

The great mass of our people do not care to waste money on
glass or tin packages of small size. They want as much as possible
of the contents, and as little as possible of the package in their in-
vestments, and we believe rhat if a strict ruling were made against
the employment of preservatives, it might prove to be a burden on
the people or else would bar the masses from using these luxuries.
It is difficult to draw the line, however, and a thorough test should
be made of all modern preservatives to determine positively their
effect upon human beings in the quantities ordinarily employed in
food products. The honest manufacturer is ready to comply with
any good national pure food law, so long as he is protected by that
law.

There are some facts concerning antiseptics which are quite
necessary to be known, and it was the author's privilege to bring
them out at the convention of state food commissioners and chem-
ists at St. Paul, Minn., in July, 1903. Various antiseptics are
formed naturally in fruits and vegetable. Various antiseptics are
formed during the processes of manufacture, especially where fer-
mentation is employed, and where sterilization is accomplished at
high temperatures. Antiseptics are formed where certain food pro-
ducts are exposed to strong sunligjr^^,

f^ OFT HE A

| UNIVERSITY J

228 CANNING AND PRESERVING OF FOOD PRODUCTS.

Prior to this convention there appeared published reports of
analyses made by 'different state chemists who claimed to have found
various antiseptics in canned goods. Knowing that certain brands
of goods had been packed absolutely without the employment of
these antiseptics, we began a series of analyses to determine their
origin. We found that the chemists' reports were true in only a
few cases, but we also found that antiseptics were formed in the
manner stated above. The chemists who had been conducting the
analyses for the people were pleased to learn the results of our in-
vestigations, which placed the canner in a far better light than ever
before. We believe that much good was accomplished at the con-
vention and that the chemists and manufacturers understand each
other better; both sides were fair and willingly heard the arguments
pro and con.

There are various fruits and vegetables which contain certain
antiseptics. Whortleberries contain 0.6 to 0.8 gram of benzoic
acid per liter (Lafar's Technical Mycology, Section 80) . ; raspber-
ries contain salicylic acid or phenol, as also does horseradish, which
will prevent the acetification of cider in one part to three hundred
and fifty. Currants contain benzoic acid and salicylic acid. Cher-
ries, plums, crabapples, grapes, strawberries, apricots and peaches,
contain salicylic acid in appreciable quantities. An analysis of
cranberries was made by the author to determine the quantity of
benzoic acid present naturally in them. From 125 grams of cran-
berries we obtained 60 milligrams of the preservative. This is
equivalent to one part to 2080, and we are quite sure that there was
still more which could not be extracted. This is a very large
amount of preservative to be found naturally in one of our finest
fruits. In Ohio or Pennsylvania any one who sells cranberries is
liable to be arrested and fined for selling an article of food contain-
ing a substance which is poisonous or injurious to health, according
to the rulings of the pure food commissioners, and the decisions of
the courts. Some of the jams, preserves, fruit butters and jellies
do not have any more of this preservative than occurs naturally in
L cranberries. Why are cranberries so valuable and so much relished
with turkey dinners? Is it not because the benzoic acid assists di-
gestion, and also prevents any decomposition of the food which the
stomach cannot quickly take care of? The benzoic acid prevents
the bacteria from multiplying until the stomach catches up with the
unusual amount of work forced upon it.

Analyses were made of two lots of green gages to determine
the presence of benzoic acid. These two lots were obtained from
different places, which makes us reasonably sure that no benzoic acid
had been added artificially. 500 grams were used, or about one
pound for each extraction, and the seeds were broken. After pre-
paring the fruit for the chloroform, several c. c. of 25 per cent sul-

PRESERVATIVES. 229

phuric acid was added, although this is not necessary. The fruit
was then placed in a separatory funnel and 125 c, c. of chloroform
was added and it was shaken up well several times. After a time
the chloroform was drawn off before the formation of an emulsion.
The extract was divided into three parts and after spontaneous
evaporation tested for benzoic acid with the Ferric chlorid test, and
benzoic acicl was found. Mohler's test w r as then used, converting'
the benzoic acid into metadiamidobenzoic acid, which confirmed the
first test. Both samples of green gages gave the reaction. Salicy-
lic acid has been found in many different fruits as shown by the

REPORT FROM MONTANA EXPERIMENT STATION.

" Among the fruits from which we have obtained the salicylic
acicl reaction are the following: Strawberries, raspberries (both
red and black), blackberries, currants, plums, black cherries, apri-
cots, peaches, Concord grapes, crabapples, standard apples and
oranges. In a few instances we have this work quantitative with
the following results :

Currants, 0.57 mg. acid per kilo of fruit.
Cherries, 0.40 mg. acid per kilo of fruit.
Plums, 0.28 mg. acid per kilo of fruit.
Crabapples, 0.24 mg. acid per kilo of fruit.
Grapes, 0.32 mg. acid per kilo of fruit.

These values, however, are not absolute, but only comparative,
and represent the amount which we succeeded in extracting in each
case. We distilled the fruit with phosphoric acicl, extracted the dis-
tillate with ether, took up with small amount of water, and applied
the ferric chloride test after the ether had evaporated. Check analy-
ses made with known amounts of salicylic acid showed that nearly
all of the acid was extracted by this method. We have also found
the salicylic acid reaction to be given by tomatoes, cauliflower and
string beans.

It seems to us that the bearing of this work is very important,
particularly as regards the investigations of food chemists. While
these very small quantities may not react to the test for salicylic
acid as usually applied, especially in view of the small amount of
material generally worked upon (25 grams), yet a knowledge of
its wide distribution may save reporting, on occasions, materials as
adulterated to which salicylic acicl has not been added. Knowing
that salicylic acid may occur in many of the substances, either a
quantitative determination will be necessary in each case, or it will
be well to report only on strong reactions.

We were led to this investigation by the protest of a well
known reputable firm, in whose currant jelly we reported salicylic

230 CANNING AND PRESERVING OF FOOD PRODUCTS.

acid, but which was present in no greater quantity than we have
since found in fresh currants. A similar experience was lately had
in one of the state laboratories for food control.

In addition to the above work we are studying the distribution
of benzoic acid in fruits and vegetables, and hope to be able to pub-
lish our results within the year."

Signed,

, F. W. TRAPHAGEN,

EDMUND BURKE."
Journal American Chemical Society.
March, 1903.

Tomatoes and acid fruits contain antiseptic properties in their
juices. Formaldehyde is present in minute quantities in almost all
foodstuff, which is exposed to the action of micro-organisms even
for a short time, and the official sulphuric acid test will show it
often I have seen milk drawn from the cow's udder and tested for
formaldehyde, which gave a positive chemical reaction. There are a
number of raw materials which undergo partial fermentation before
they are worked into finished food products. During that fermenta-
tion there are formed various chemicals which are elaborated by bac-
teria: such as phenol, formic acid, sulphites and nitrates, and enough
of these substances may be present in the finished goods to give
the reaction in the official tests. Among the products which under-
go fermentation as a part of the manufacturer's process are pickles,
olives, onions, sauerkraut, tomatoes for catsup, cauliflower, herbs,
garlic, soaked goods such as navy beans ; pickled meats and various
other raw materials.

There are formed in some canned goods during sterilization at
250 F., such compounds as formic acid, formaldehyde and dioxy-
gen, \vhich are due to the oxidation of fats and sugars. Some of
these are formed always in canned corn, principally formaldehyde.
In the presence of sunlight also certain raw materials and even fin-
ished goods will form chemicals having strong antiseptic proper-
ties, dioxygen being the most common (Novy's Laboratory Bac-
teriology, page 70). Milk, when heated only to 212 F., will show
the presence of formic acid and formaldehyde, and at 250 F. these
give a very marked reaction, and the milk undergoes chemcial
changes, such as the precipitation of calcium citrate and the forma-
tion of dark fission compounds having an empyreumatic flavor.
(Attested by numerous authorities.)

Xow we must not understand by all these statements that
enough of these antiseptic compounds are formed to arrest decom-
position ; indeed, such is the case only with a very few, and even in
those, decomposition will eventually take place, but these facts are

PRESERVATIVES. 231

brought out to show that there may be some ground for the chem-
ists' report on certain goods when they state that these antiseptics
are present. On the other hand, these facts will serve the chem-
ists and should enable them to make allowances for products formed
during the process of manufacture, or those which have a natural
origin in raw material, used in making up the finished food product.
By conducting control tests and making a careful study of raw ma-
terial, the chemist will be in a position to state positively if antisep-
tics are purposely added, or whether they are of natural origin.

From the very fact that nature produces so many examples of
the natural formation of compounds with marked antiseptic prop-
erties, it would seem that the manufacturer might be allowed to
follow nature's example in some cases.

So much has been written and said on the harmfulness of pre-
servatives in food within the last ten years that any further discus-
sion might seem unwarranted. However, the subject is one of
such vital importance to manufacturers of certain Food Products
and Table Condiments, that any information of importance cannot
fail to be interesting. A few years ago the warfare waged against
the employment of salicylic acid became so strong, that laws were
rapidly passed to stop its use in every article intended for food and
drink. After the passage of these laws, the writer was one who
strongly urged the manufacturers to cease using the chemical. At
that time the question was one of obedience to State authority, how-
ever dictatorial it might seem. In the absence of means and data
to refute the charges made by famous medical and scientific author-
ities, the manufacturers saw the measures presented and passed
against them without being able to oppose them. I have always
stood for strict obedience to the laws governing the employment of
preservatives in Canned Goods, and so far as possible in other food
products, but we need a thorough test of the statements made by
the authorities who were responsible for the measures set against
preservatives.

Personally, / believe that salicylic acid one part in one thou-
sand is not only non-infnrions when employed in foods and drinks,
which arc necessarily exposed to the action of bacteria, but is posi-
tively beneficial, having a tendency to ward off intestinal diseases,
such ns typhoid fever and cholera.

I do not wish to be misunderstood in this discussion of preser-
vatives. So long as the laws prohibit the sale of or exposing for
sale of goods preserved by means of salicylic acid, let us as manu-
facturers, by all means live in obedience to them, and if we desire
a change in the statutes, let us go about it in a way that will over-
throw the statements made by those authorities who are responsible
for the enactment of such laws. Our first step therefore will be to

232 CANNING AND PRESERVING OF FOOD PRODUCTS.

analyze the statement of these authorities and present facts which
shall overthrow any theories, and if not entirely successful, to at
least throw some shadows of doubt on them, it is an old saying
that a statement never loses anything by repetition ; on the contrary,
it gathers force and volume as it is repeated, so that a simple doubt-
ful statement is sometimes expanded by frequent misquotation into
an apparently positive fact. In the world of science we find that
much of the literature is merely a copy of a true investigator's work,
and we are mystified frequently by statements directly opposite com-
ing from supposed authorities. Much of the scientific literature
of the time should probably never have seen the light of day. be-
cause the statements made are sometimes not borne out by facts.
We find this state of affairs existing in the field of science, where
a writer presumes to quote some other writer as an authority. Prob-
ably the preceding writer misquoted an investigator, and a positive
error is put down in a text-book under the authorship of one, whose
titles protect him from vulgar criticism, when the fact is he was per-
haps too preoccupied to make the investigation for himself.

Dr. J. Dixon Mann is one of the most bitter opponents of sali-
cylic acid in food and drink, and his evidence was accepted by the
British Parliamentary Inquiry Commission, and is a sample of much
similar evidence also accepted. I make the quotation in full so that
no mistake may be made in the discussion : ''Last year in the sum-
mer, at lunch in the club, I took to drinking. cider and continued
taking it for many weeks. I began to feel a peculiar tendency to
looseness in the bowels; furthermore, I felt never, as it were,
thoroughly relieved after motions. This went on for a time and I
could not understand how it was. I thought it was accidental in
the first place, but it kept going on week after week. I did not
care to take any medicine and I began to cast about for what possi-
bly could be the cause of it. I went over the things I had been
in the habit of taking, and the things I was taking at the time. I
could not think of anything until it struck me about this cider; so
I got a bottle of the same sort from the steward of the club, took
it to my laboratory, and found salicylic acid in it, and, needless to
say, I have not taken cider since." I want to call particular atten-
tion to the last few clauses of this testimony : "And found salicy-
lic acid," etc. Why did he not look for malic acid, succinic acid or
some other substance? No, he found salicylic acid and jumped to
the conclusion that it was the cause of his particular complaint. If
he had shown a true scientific spirit, is it not reasonable to suppose
that he would have made a qualitative analysis of the salicylic acid
contained in the usual amount of cider which he was in the habit
of drinking- each day? After a time, when he was in perfect health,
he could have taken the same amount of the acid mixed with other
food, and then obtained more direct evidence.

PRESERVATIVES. 233

It is a source of wonder to me that such an eminent body of
men as composed the Parliamentary Inquiry Commission should
accept such evidence.

The demand for preservatives to prevent fermentative and put-
refactive processes in certain kinds of perishable food is so great,
and the interests involved are so enormous, that snap judgment
should not be taken against them.

I have always written against the unnecessary employment of
preservatives in canned goods or other foods which may be steril-
ized by heat only, for the reason that it is expensive, unnecessary,
and it is not wise to overdo the thing. It would not be wise to pre-
serve every thing with salt, it would not agree with us to have too
much of it harmless and necessary as it is, but we are quite satis-
fied to have our hams, sausage, pickles, etc., so preserved. It would
not be wise for us to preserve all our food with sugar, it would soon
make us all sick, but we are satisfied to preserve our fruits, jellies,
jams, etc., with it, because at times we relish the change of diet. .
It would not be wise for us to preserve all our food by smoke (which
is an application of creosote, phenol, etc.) ., but we are satisfied to
have some of our meat put up in this fashion. It would not be wise
to preserve all our food by sterilization in hermetically sealed pack-
ages, because we want a change, yet we are satisfied to have a great
variety so put up for winter use. Therefore an indiscriminate use
of salicylic acid would be unwise, but when restricted to such foods
as are subject to chemical changes by bacteria, it. would be the part
of wisdom to permit its use, provided it is not injurious to health.

It has been so declared by a number of authorities on the fol- -
lowing grounds :

1. "It is an antiseptic and anti-fermentative, and is therefore
liable to interfere with the digestive processes by destroying the
digestive ferments."

2. "After absorption it is apt to injure the general health, and
to interfere with nutrition."

3. "It is an irritant, and is therefore apt to injure the mucous
membrane of the stomach and intestinal canal."

In the report of the Department Committee appointed to in-
quire into the Use of Preservatives, etc., presented to both Houses
by command of His Majesty, London. 1901 (page 96), is the testi-
mony of Dr. Robert Bell, Fellow of the Faculty of Physicians and
Surgeons of Glasgow, and Fellow of the Royal College of Surgeons
of Eclinburg. He stated that he and his family had knowingly and
regularly taken food containing antiseptics for eighteen years and
without a sign of harm to any of them. "During the whole of that
period we have never had a single case of illness in the house; when
scarlet fever, measles, whooping-cough and other ailments were

2U CANNING AND PRESERVING OP FOOD PRODUCTS.

rampant, there was not a single one of our children ill. There is
another family that I know very much in the same position as our-
selves."

In papers read before the Liverpool Medical Institution on
November 20, 1902, by Dr. C. J. MacAlister, of Edinburgh, and
Dr. T. R. Bradshaw, of Dublin, they gave their experiments with
salicylic acid on digestive processes, and the digestive ferments.
Quoting their report fully they said : "In this inquiry we have no-
thing to do with the organized living ferments (bacteria, yeasts,
molds, etc.). ; these are certainly killed by salicylic acid, and its
efficacy as a food preservative depends upon that very fact ; but we
have found that the digestive processes will proceed in the presence
of the acid even in a solution of i to 500, which is practically satur-
ated.

Our first experiment was made with pepsin which, if active,
should dissolve 2,500 times its weight of hard-boiled egg, and the
Pharmacopoea provides the following test for its activity: "If 12.5
grams of coagulated and firm white of egg, 125 c. c. of acidulated
water containing 0.2 per cent muriatic acid, 0.005 gramme of pepsin
be digested together at 105 Fahr. for six hours and shaken fre-
quently, the coagulated white of egg should dissolve, leaving some
flakes in solution. Having ascertained the activity of a specimen
of pepsin by this experiment, we repeated it in two flasks each con-
taining the above specified ingredients in their proper proportions,
but to one of the flasks 0.250 gram of pure salicylic acid (which
had previously been dissolved in eight c. c. of boiling water) was
added, and at the end of six hours it was found that in the flask con-
taining salicylic acid, there was only a small amount of white of
egg left, none being left in the other flask." They go on to say,
however, that the addition of salt to a tube containing pepsin and
white of egg gave practically the same results, then they sum up
the results of their experiments in words as follows : "We have
found that salicylic acid exerts about the same retarding influence
on the digestive processes, as do many articles, such as kitchen salt,
which are always present in a mixed diet. . . . the question therefore
is not whether salicylic acid delays digestion at all, but whether it
does so to a greater extent than other bodies, such as kitchen salt,
which form part of an ordinary diet."

The experiments of these two eminent authorities bring out the
fact that salicylic acid does not interfere with natural digestion, and
makes a clear distinction between organized or living ferments, such
as bacteria, yeasts and molds, and the unorganized ferments or di-
gestive enzymes, pepsin being most prominent. The opponents of
salicylic acid have never shown the proper spirit of investigation.

PRESERVATIVES. 235

but rather a kind of theoretic deduction, jumping from one hypothe-
sis to a conclusion without the solution somewhat after this style.

HYPOTHESIS Salicylic acid destroys bacteria which are
ferments.

CONCLUSION Therefore digestive processes are impeded
because they depend upon ferments.

"\Ye can readily see, therefore, how false the conclusion must
be if it is made to depend upon the hypothesis, where the bacteria
are called ferments without differentiation from unorganized fer-
ments such as pepsin. We know that the living ferments are de-
stroyed by the change produced in the cell protoplasm, resulting in
plasmolysis, but in the unorganized ferment there is no cell proto-
plasm and the action of the preservative cannot therefore be the
same.

It should also be borne in mind that the opponents of salicylic
acid have generally taken abnormally strong solutions of salicylic
acid, to maintain their claims. Xo person ever takes this acid at
meal time as strong as a cold water solution, yet this is a favorite
(amount employed in experiments,) by those who would convince
the people that they are dying of slow poisoning.

An official of the Department of Agriculture recently stated
that "The burden of proof, that preservatives are harmless to man,
rests with the manufacturers who use them.'* Such a statement,
when closely analyzed, is a deduction drawn from the testimony of
various medical authorities which have declared that preservatives
are poisons and injurious to man. It implies that since preserva-
tives have been so declared by those who ought to know, direct evi-
dence to the contrary must be produced by manufacturers who use
them. Therefore, some of them stand condemned as harmful, be-
cause many authorities have stated that in their opinion such was the
case.

The task of proving the fallacy of many statements advanced
by the opposition is no easy one. The public mind is already to
some extent prejudiced against preservatives in food, simply be-
cause some authorities have made the assertion that they were harm-
ful. There are a number of condiments which are commonly pre-
served with such chemicals as salicylic acid, benzoate of sodium,
and borax, the last two particularly. The condiments so preserved
may be sterilized by heat only and they will remain pure and unfer-
mented as long as the container is hermetically sealed. As a rule
these condiments have a very delicate flavor which is greatly injured
by .1 sterilizing process sufficiently prolonged to destroy the yeasts,
molds and spores of bacteria present in them. I have been con-
ducting a series of experiments with such goods for the past six
years. Many carloads of condiments put up in glass and sterilized

236 CANNING AND PRESERVING OF FOOD PRODUCTS.

by heat only have been sent out to the trade. It is a remarkable
fact that such goods have failed to give general satisfaction for
three reasons. They have a slightly scorched taste, or a pasteurized
taste and odor. The natural color is somewhat darkened and the
goods soon spoil after the containers are opened. We have found
that tomato catsup which has been sterilized by heat only is greatly
injured in flavor and will not keep for more than five clays after the
bottles are opened. Frequently fermentation sets in about the third
or fourth day and mold will be visible to the eye in four or five days.
Another remarkable fact brought out in these experiments was
the preference shown by the consumers for condiments prepared
with preservatives over the same goods sterilized by heat only. In
many cases the facts were made clear to the consumer. The conse-
quence was that much of the pure goods still remains unsold on
the grocer's shelves, while those prepared with preservatives are
selling rapidly.

Catsup both with and without preservatives, has been placed
throughout Kentucky, Minnesota and the Dakotas, and a large
per cent of that sterilized by heat only remains unsold, and the trade
has been greatly injured owing to the loss of flavor.

Now let us examine the reasons for this difference in flavor.
Why is it that the flavor is injured more by heat than by preserva-
tives. It is well known that preservatives destroy flavor, especially
if used in excess, and we know that heat will not injure the flavor
very much unless it is prolonged.

In preparing table condiments with preservatives, the manu-
facturer does not plan to destroy the organized ferments such as
molds, yeasts and bacteria, but to prevent their multiplication or
growth. The chemical changes caused by fermentation are pro-
duced during the multiplication of the organized ferments. The
elements necessary for the multiplication of ferments are obtained
from the carbohydrates and other complex substances, and there are
formed new chemical compounds greatly differing in taste and odor
from the original substance. Therefore preservatives are added in
just sufficient amounts to prevent the multiplication of these fer-
ments. No attempt is made to destroy them, because, as a rule,
they are non-pathogenic and are not harmful to the human organ-
ism in small numbers. Very few of the preservatives ordinarily
used in preserves, apple-butter, tomato catsup. Chili-sauce, etc., are
antiseptic, strictly speaking, and certainly they are not germicidal
in the quantities used. This accounts for the spoilage of such con-
diments after a time, because ordinary preservatives finally lose
their preventative power.

Sterilization by heat only is a far different problem. All spores
of yeasts, molds and bacteria must be destroyed absolutely. One

PRESERVATIVES. 237

or two spores are just as dangerous as millions, if they remain alive.
From one spore there will spring into existence many millions of
the same species within a very short time, where the temperature
and other conditions are favorable. In order to completely sterilize
table condiments considerable heat is necessary, owing to the density
of the goods and the size of the container. Goods of this kind are
usually sold in glass, because tin is not suitable for them, owing to
their high acidity which attacks the tin plate vigorously. Steriliza-
tion requires boiling for perhaps thirty or forty minutes to destroy
all spores. The organisms near the outside, of course, perish
quickly, but those in the center do not get the required temperature
for a considerable time, varying with the diameter of the container
and the density or penetrability of the goods. Certain portions of
such packages, therefore, receive more heat than is necessary for
the destruction of ferments, and of course, the flavor suffers ac-
cordingly. If such goods could be heated uniformly, the loss of
flavor would still be greater than in the same goods containing pre-
servatives sufficient to inhibit bacterial growth, because complete
destruction is necessary in the one, while inhibition only is necessary
in the other.

Our claim for the necessity of preservatives in food of slow
consumption is a good one, because it has been demonstrated that
the people prefer such goods with as near the natural flavor as it
is possible to make them, and sterilization by heat does destroy much
of the original flavor. Our conclusions are thus summed up :

J. The ordinary preservatives employed for preserving goods
of slow consumption are valuable and necessary, because in no
other way can the original flavor of such goods be retained.

2. The consumer prefers this class of goods even when he
knows that preservatives have been used to keep them in an unfer-
mented state.

This does not dispose of the question, "Are such preservatives
harmful to the human organism ?" but it is encouraging to note that
the consumer is better pleased with table condiments so preserved.

The testimony offered before the Parliamentary Committee
by a large number of physicians and professional men is interesting,
and is remarkable for its utter lack of evidence based on experi-
mental investigation. One physician after another is called before
the committee, and nearly all evidence is founded on mere opinion
or the result obtained by abnormal quantities of preservatives. True
investigation had not been made by many, and those who had done
any experimental work did not produce the notes and data to prove
their claims. The following testimony was offered as evidence be-
fore the Parliamentary Committee. From the Blue Book, No.
5745-46.

238 CANNING AND PRESERVING OF FOOD PRODUCTS.

MR. HENRY DROOP RICHMOND.

Question. "With regard to the action of salicylic acid on
enzymes, is your opinion of that subject based upon what you have
read or upon what you have done ? You say that salicylic acid has
an action on the enzymes."

Answer. "I think it is chiefly based upon what I have read.
I have also found that the action of certain enzymes, diastase for
instance, is stopped by salicylic acid.''

The first part of this testimony is indeed very like that of many
others. Nearly every opposed authority, when called upon to ex-
press his opinion as to the action of salicylic acid on enzymes, al-
most unhesitatingly states that it is his opinion that this preserva-
tive retards, or prevents the digestion of food in the stomach and
when pressed as to the basis of his opinion, like every one of his
predecessors, he states that he has read it. Probably the author of
the book also read it as a quotation from some author in the middle
of the last century.

Digestive processes were unknown up to the time when Theo-
dore Schwann in 1836 discovered that the gastric juice contained
pepsin, and it was only three years previous that Payen and Perzos
discovered diastase in malt extract. All literature previous to the
discovery of enzymes and organized ferments made no distinction
between them.

This idea has been carried down in various scientific works ever
since, and it is no very uncommon thing to read extracts (which
contain the essence of this fallacy), published within the last few
years by authorities who have never given this subject any inves-
tigation.

Fermentation is a term very greatly misinterpreted; it is re-
peatedly treated as a process which is brought about by bacteria,
yeasts, and molds, and likewise by the enzymes of digestion. This
is a great error, and finds expression in such productions as the fol-
lowing :

North Dakota Agricultural Experiment Station. Bulletin 53.
Page 119. In the Minnesota Dairy and Food Commissioner's Re-
port for 1901 this statement appears preservatives "are used solely
to prevent fermentation and since the processes of digestion are
fermentation processes, the chemical preservatives must work an
injury." And also,

In Bulletin 100 of the Kentucky Agricultural Experiment Sta-
tion, a well-known officer of the State Food Commissioners' Associ-
ation says : "The strong paralyzant power claimed for antiseptics
is sufficient to condemn their use in foods, for a substance which
can preserve perishable foods under any conditions, and for any

PRESERVATIVES. 239

length of time, will also affect the delicate digestive ferments of the
stomach," and he quotes a government authority in these words :
"There is no preservative which paralyzes the ferments which cre-
ate decay, that does not at the same time paralyze to the same ex-
tent, the ferments that produce digestion. . . . The very fact that
any substance preserves food from decay shows that it is not fit to
enter the stomach."

I was much surprised that the authority mentioned in Bulletin
100 by the writer of that article should have made such a statement,
so when in Xew York later I asked the gentlemen, who is a mem-
ber of the Committee on Food Standards, if he had been quoted
correctly, and he stated that he had never authorized that state-
ment. It is, therefore, up to our Kentucky friend to verify his quo-
tation.

So far as I am aware this statement did not appear in print
until Bulletin 100 brought it out, and it has been copied and changed
to fit any argument opposed to preservatives by the daily press and
the authorities in many states. In the light of modern research it
is ridiculous. Any investigator could prove its falsity in a few
hours' experiment. Every physiologist knows that hydrochloric
acid is present in the stomach and is absolutely necessary in the
digestive process. Every one knows that it is an antiseptic, and it
is frequently combined with such disinfectants as bichlorid of mer-
cury to increase their antiseptic properties, which it does, from 50
to 100 per cent. It will absolutely prevent the multiplication of
bacteria in 0.2 per cent solutions, which is the amount found, in
the normal stomach during digestion. Yet if we were to accept the
statement quoted in Bulletin 100, we would expect to have our di-
gestive apparatus completely paralyzed after every meal.

The bile acids are antiseptics, principally taurocholic acid,
which is nearly as powerful as salicylic acid, so affirmed by the
following authorities: Lindenberger (Bulletin de la Societe imp.
des naturalistes de Moscow, 1884) ; also Bunge's Physiological and
Pathological Chemistry, second edition, pages 184 and 185, quotes
as authority Maly and Enrich Monatshefte (Chemistry, Vol. IV,
page 89) ; also Gley and Lambling (Revised biology du Nord de la
France, Vol. I, 1886.)

After every meal, when the food reaches the duodenum, the
bile flows into it carrying the antiseptic taurocholic acid, and not-
withstanding the statement that antiseptics paralyze the ferments,
the digestion is stimulated instead. We are almost ready to turn
the argument quoted by our Kentucky writer and make it apply in
the opposite way, thus, "the ferments that produce digestion are
stimulated by antiseptics in the same proportion that the organisms
which produce decay are paralyzed."

240 CANNING AND PRESERVING OF FOOD PRODUCTS.

Prof. Prescott, of the University of Michigan, is quoted in
Bulletin No. 53, page 118, of the North Dakota Agricultural Sta-
tion, as follows : "A food that is braced against decomposition may
be found to be braced against digestion." I am quite sure that the
author never intended this to be garbled in this manner by anyone,
because the statement has an element of truth in it. Antiseptics are
not used to completely brace foods against decomposition ; indeed
it may be truly said that manufacturers of table condiments such
as catsup, Chili-sauce, apple-butter, peach-butter, preserves, jam,
jellies, etc., do not use preservatives to completely retard decom-
position, but to assist the sugar and the container to arrest fer-
mentation until such foods are consumed. It is well known that
any of these manufactured products will spoil within a certain time
after the original package is opened. Then again, some foods are
chemically changed by high temperatures so that they become in-
digestible. Even the dark brown crust of bread is thus changed by
heat in the baking process. Milk is changed to some extent in pas-
teurization and complete sterilization. Then again the author
quoted uses the words "may be'' because he undoubtedly recognized
the fact that his statement could not apply in all cases and be made
to do duty as an argument against preservatives in general.

In the report of 1892, of the Committee on Interstate and For-
eign Commerce of the House of Representatives, on the pure food
bills, page 395, it is stated that "Prof. Mitchell, of Wisconsin, con-
siders any active antiseptic necessarily deleterious to health. It
retards the processes of the stomach, stopping the working of the
normal enzymes or ferments/'

In the light of our experiments with salicylic acid and pepsin,
and from what we know of hydrochloric acid and taurocholic acid,
such statements as that of Prof. Mitchell are ridiculous. Here
again we have an opinion given with no data or experiments to
prove it true, and that opinion is on record to be quoted as an es-
tablished fact for years to come. Now here is another opinion
which is directly opposite to the statement made by Prof. Mitchell.
The professor of Physiological Chemistry at Yale University de-
clares that "Antiseptics do not interfere with digestion" (page 396
of the same report). This opinion, coming as it does, from such
high authority, and based upon personal investigation, as we know
it to be, throws a shadow on the professor from Wisconsin. Here
is another opposing opinion by Dr. E. H. Starling, Fellow of the
Royal College of Physicians and a Fellow of the Royal Society.
(Blue Book Report of the Parliamentary Committee No. 6941, page
2 43-)

Question. "What have you to tell us as regards salicylic
acid?"

PRESERVATIVES. 241

Answer. "Salicylic acid is certainly harmful, less, however,
than formalin. In an acid medium, that is to say, the medium in
which the stomach digestion goes on, it acts as an antiseptic, but in
the stomach where it is acting as an antiseptic, it also prevents the
action of the gastric juice and stops digestion in the stomach.
Clinically, of course, one knows that the use of salicylic acid, especi-
ally in the free state, is apt to cause symptoms of gastric dyspepsia,
pain in the stomach, and stoppage of gastric digestion, etc."

This authority states in the beginning of his testimony, that
he had made physiological experiments with salicylic acid, but he
does not state what they were, nor how they were made. He does
not state whether he used small doses or whether he administered
abnormal quantities. We know that his testimony as to the stop-
page of digestive processes in the stomach is absolutely false, if he
used less than one part to 500, because we have demonstrated by
actual experiment that digestive processes are a little delayed but not
entirely stopped, as he stated the case. In quantities less than one
to 500 the delay is not noticeable and in either case the delay is no
greater than that caused by many substances, such as common salt,
coffee, tea, etc., which enter the stomach in a mixed diet.

Clinically, salicylic acid is a fine remedy for fermentation,
caused by living organisms in the stomach. It not only destroys the
bacteria, but actually assists the gastric juices in the digestion. Two
cases of this nature have come under my personal notice, so this
would indicate that the testimony of Dr. Starling was not as sci-
entific as it should have been. He goes on to say, "When the food
gets down to the intestines, where the medium is alkaline, and where
it is attacked by the pancreatic juice, salicylic acid does not disturb
digestion, and there, of course, it does not act as an antiseptic/'
Late investigation has shown that salicylic acid is decomposed in
the stomach into carbonic acid and phenol, which are carried off
by the urine.

Prof. William Henry Cornfield was called before the com-
mittee and testified as follows : "I have had very little practical ex-
perience on the results of the internal administration of salicylic
acid, but I have studied the effects of it as they have been observed
and published by others." This statement was all right, and he
probably said just what all the other witnesses should have said,
but he goes on with his testimony just as if he had made a deep
physiological and chemical research. Note his answer to question
5067 (page 177). "Suppose a person were taking a small quantity
of salicylic acid day by day, is it certain he could get rid of the
whole of that quantity in each day?" Answer "I do not think it
is." Question No. 5077 (page 177) : "Might there be a tendency

242 CANNING AND PRESERVING OF FOOD PRODUCTS.

to accumulation?" "Yes; I think there is evidence that there is
a tendency to accumulation with that drug."

As we stated before, there is no evidence to show anything of
the sort, and it is well known that salicylic acid and some other
preservatives are almost entirely excreted in the urine and perspira-
tion. Like all chemical work this test -shows a very slight amount
which cannot be accounted for, but when the decrepancies are taken
into consideration in other analytical work, it is a fair presumption
that the unaccounted per cent, is a chemical decrepancy due to in-
accuracy in analysis.

I have been impressed while reading over a large amount of
testimony offered on various preservatives, that only rarely is
a specific quantity named. We have all along presumed that no
greater amount of preservative should be used for physiological
research work than it is possible for anyone to actually consume
daily in food. This is not more than one part in 500 in some few
articles, and not more than one part in 2000 in others. It is hardly
likely that anyone would eat as much as one part of salicylic acid to
1000 parts of general food and fluids. This proportion would be very
high indeed, and I do not believe that such an amount of preserva-
tives is ever used continuously by anyone.

Any physician could say that certain amount of preservatives
would prove harmful, and the same thing could be said of fire
a certain amount of heat is absolutely necessary, but we cannot
reason that because a certain amount of heat will burn us that we
should not use heat such reasoning would be absurd. Heat is
good, but too much of it must certainly stop digestion ; sugar, salt,
coffee, tea, etc., are all good in certain amounts, but too much of any
will stop digestion, therefore any testimony which does not specify
a fixed amount of preservative that is harmful has no value as evi-
dence, except in Pennsylvania.

We have gathered considerable evidence, as our readers have
found, to show that the statements by various authorities on the
harmful action of salicylic acid on gastric digestion are not strictly
in accordance with facts. We have yet to speak of the argument
advanced by several investigators to the effect that the diastatic
enzyme, ptyalin of the saliva, is stopped by such preservatives as
salicylic acid and benzoic acid.

In order to answer this argument, put up by Prof. H. A.
Weber and others, we must outline the whole digestive process and
consider the nature of each enzyme, and then learn how wisely Na-
ture has planned the whole apparatus so that disturbances in one
quarter do not necessarily disturb the whole process.

The ptyalin or diastatic enzyme of the saliva is secreted in an
alkaline fluid, and its process is carried on in an alkaline fluid.

PRESERVATIVES. 243

(Gamgee's Physiological Chemistry of the Animal Body 1893,
pages 23-27).

The pepsin or albumen digesting enzyme is acid and requires
the presence of an acid ; even small quantities of alkaline solution
render it inert. (Langley, Journal of Physiology, III. page 246).

The trypsin or albumen digesting enzyme of the pancreas
"works best in a weak alkaline solution.'' (Ferments and Their
Action, page 39, Oppenheimer.) Weak acid solutions do not great-
ly interfere with it, but any solution containing as much acid as the
gastric juice (estimated at 0.2 per cent.) would stop this enzyme.

Now this is certain, therefore, that any acid or alkaline taken
either as a food or in food, must have some influence on one or more
of these enzymes. It is the acid in such preservatives as salicylic and
benzoic acids that has a retarding influence on the diastatic enzyme
of the saliva. If this action is to be considered harmful by the op-
ponents of preservatives, and if this is to be considered as a reason
for prohibiting preservatives, then the same objection must be filed
against every acid food. Lemonade, phosphated drinks, acid fruits
of all kinds, have a far greater influence on the ptyalin than all the
added preservatives one could take in food, as it is now prepared.

The pepsin of the gastric juice is retarded by all alcoholic
drinks, beer, wine, etc. "Beer, even when containing less than three
per cent, of alcohol, has a strong restrictive action, and this is not
to be ascribed to the hops, since wine has the same effect." (Fer-
ments and Their Action, page 96; also Buchner, Arch. f. klin. Med.,
XXIV. 537.)

Tea and coffee also retard the action of the pepsin on coagu-
lated egg albumen, demonstrated in National Canners' Laboratory,
June "Index," 1904. Frazer also authorizes this conclusion.
(Journal of Anatomy and Physiology, XXXL, page 469.)

The amount of salt usually taken in a single meal retards peptic
digestion as much, if not more, than all the preservatives taken in
food during the same meal. (National Canners' Laboratory Re-
port for May "Index," 1904.

Now note the following: "The gall normally precipitates the
pepsin, but when this function is absent e. g., in fistula the pep-
sin penetrates into the intestines and destroys the trypsin to a more
or less pronounced extent, and thereby the digestion of the albumen
is checked." (Ferments and Their action, page 109.)

The arguments based on the ground that preservatives should not
be used in food, because they restrict or retard the digesting enzymes,
grow very weak in the face of the facts presented here. If our
physical economy were so delicately constructed and so easily upset,
we would all be constant sufferers from indigestion. Nature has
provided a way to neutralize acids and salts and means of throwing
off unnecessarv and undesirable substances.

244 CANNING AND PRESERVING OF FOOD PRODUCTS.

Since it has become known among scientists that the preserv-
atives commonly used in food products are largely excreted by the
kidneys, a claim has been set up that the extra amount of work
which is forced upon these already over-worked (?) organs, will
necessarily lay the foundation for kidney diseases of various kinds.
In Bulletin No. 100 of the Kentucky Agricultural Experiment Sta-
tion, page 101, speaking of preservatives, the writer says that "they
are eliminated by the kidneys and that such elimination gives rise
to various forms of kidney trouble."

This statement is made without any quotation from medical
literature to sustain it, and the reason is obvious,- since no such
statement is thus made, so far as I am able to find. A question
was once asked of a noted physician, "Within the last few years
Bright' s disease has increased, and is it not possible that preserva-
tives in food products might be one of the principal causes?" He
answered that he did not think so, because there are several other
causes at work, which had such direct responsibility for kidney dis-
eases, that it was hardly likely that preservatives commonly used
in food products were in any way contributory; that more kidney
diseases were directly caused through invasion by micro-organ-
isms, such as the gonococcus and bacterium pyocyaneus, also
streptococcus and staphylococcus aureus et al; and since such
increase of gonorrhoeal infections has been reported by the var-
ious medical societies, kidney diseases may be traced in many cases
directly to this malady. It is reasonable to suppose that preserva-
tives would have an antiseptic influence on micro-organisms which
invade the kidneys, and as antiseptics they would prove beneficial,
as indeed they are, and are prescribed in medicinal doses for that
very purpose. There is a theory that antiseptics taken in food con-
tinuously must exert an irritating influence on the kidneys, and
eventually must cause abnormal changes, followed by the invasion
of micro-organisms.

The kidneys are endowed by nature with the power to dis-
solve all kinds of irritating and poisonous substances from the blood
stream, and afterwards to expel them through the urine, so it is not
a fair presumption to suppose that they are injured because certain
substances are supposed to have irritating properties. We should
naturally expect to find some evidence of irritation on the mucous
membrane of the stomach prior to any injury of the kidneys. In
cases of Bright' s and kindred diseases, the post mortems often re-
veal the fact that the stomach is normal in every way, and this
would seem to prove that hyperplastic processes were caused
through invasion by bacteria.

There is very little medical testimony to prove that diseases of
the kidneys are due to overwork in eliminating substances which

PRESERVATIVES. 245

pass unchanged through the body. One writer has mentioned salt
as a substance excreted by the kidneys. This chemical passes
through the body as sodium chlorid and does not cause any ab-
normal processes of kidney degeneration. Another writer speaks
of water as a substance which passes unchanged through the body
and is excreted by the kidneys without any injury to them; there-
fore, it is not a sound argument that because a substance passes
unchanged through the body, it must overwork the kidneys.

There are probably no organs of the human body more ad-
mirably capacitated for work than the kidneys. There are two
of them, and ordinarily there is very little more than enough work
for one ; the other is always ready, however, to assist in the elimina-
tion of foreign substances from the blood stream. Some experi-
ments have been made with animals to determine working capacity
of the kidneys, and it was proven that three-fourths of a kidney
could be cut away before any serious consequences could be detected.
(Albutt's System of Medicine, Vol. IV., p. 318.)

Americans consume large quantities of nitrogenous foods
and an unusual amount of work is forced upon the kidneys in order
to expel the nitrogen, but there are a number of cases on record
where human beings have lived for many years with only one kid-
ney, which had to do all the work devolving upon these organs.
This would indicate that any person having two normal kidneys
would not be seriously overworking them by allowing them to ex-
pel a very small quantity of such preservatives as salicylic or benzoic
acid.

The kidneys must excrete the uric acid from the body, and
salicylic acid is helpful in its removal, and for this reason the pre-
servative is given as a remedy for rheumatism. (Practical Thera-
peutics-Hare, page 341.)

Salicylic acid unites with glycin, forming salicyluric acid;
also, benzoic acid unites with glycin, forming hippuric acid, and both
of these antiseptics are, therefore, helpful in assisting the kidneys
to expel the glycin, or as it is commonly called glycocoll, or amido-
acetic acid. (Cushny-Pharmacology and Therapeutics, page 417.)

In the London Lancet of November 25, 1899, P a R e I A 2 7>
Cushny rather opposed salicylic acid, because it was excreted from
the body in a form unlike any product of normal urine, but he did
not oppose benzoic acid because it was excreted as hippuric acid,
which is found in normal urine.

Dr. R. G. Eccles has pointed out the false reasoning in this,
however, because:

Salicyluric acid is salicylic acid plus glycin.

Hippuric acid is benzoic acid plus glycin.

In other words, there is very little difference between the two,
salicylic acid being simply equivalent to hippuric acid plus water.

246 CANNING AND PRESERVING OF FOOD PRODUCTS.

"As glycin or glycocollic acid is a precursor of urea, its remov-
al by means of salicylic or benzoic acid, aids the body in getting
rid of its waste product." (American Text-book of Physiology,
page 981, also Foster's Text-book of Physiology, page 539.)

It would seem from this that preservatives such as these are
beneficial rather than detrimental. Normal kidneys cannot be in-
jured by them, and since they are antiseptic by nature, it is fair to
presume that any one who is suffering with kidneys diseased by
invading bacteria must be benefitted by the preservatives which have
inhibitory influence upon bacterial life, providing that such antisep-
tics are not taken in doses large enough to be irritating or to cause
cellular metabolism.

PRESERVATIVES. 247

CHAPTER VIII.
Preservatives Continued

Experiments With Preservatives and Other Substances to Deter-
mine Their Effect on Peptic Digestion. Physiological and Path-
ological Research Work With Animals Fed on Salicylic and
Benzoic Acids. Post Mortems. Conclusions.

EXPERIMENTS WITH PEPSIN.

A number of flasks were prepared, using the formula for test-
ing the activity of pepsin given in the Pharmacopoea. A series
of experiments were made as follows :

Flask No. I.

\2,y 2 grams hard boiled white of egg.
125 c. c. pure water.
0.2 per cent, hydrochloric acid.
0.005 gram of pepsin.

Flask No. II.

Just the same as No. i with the addition of Y^ gram of salicylic
acid dissolved in water.

Flask No. IIL-

Just the same as No. I with the addition of l /\ gram of com-
mon salt.

Flask No. IV.

Just the same as No. i with the addition of one loopful of
Bacillus Vulgaris and one loopful of a bacillus found in corn.

All these flasks were kept for six hours in the incubator at a
temperature of 150 F. and agitated frequently.

No. i showed only a few flakes, and all the rest had a small
quantity of egg still undigested. After two or more hours these
were just like No. i.

This proves that salicylic acid in very strong solutions does not
impede digestion more than other substances consumed in a mixed
diet, common salt retarding fully as much as the acid. Ordinary
bacteria taken at meal time have the same retarding influence, al-
though the amount of hydrochloric acid used prevented them from
propogating.

248 CANNING AND PRESERVING OF FOOD PRODUCTS.

In order to test the retarding influence of various substances in
comparison with preservatives, a number of flasks were prepared
as follows :

Flask No. I-

125 cubic centimeters of water.

12.5 grams of hard boiled white of egg, finely divided.

0.005 gram of pure pepsin.

0.2 per cent hydrochloric acid.

Flask No. II-

Just the same as No. I with the addition of 0.25 gram of pre-
servative commonly used in food products. Benzoic Acid.

Flask No. Ill-
Just the same as No. I with the addition of 0.25 gram of
ground coffee.

Flask No. IV-

Just the same as No. I with the addition of 0.25 gram of green
tea.

Flask No. V

Just the same as No. I with the addition of 0.25 c. c. of absolute
alcohol.

Flask No. VI-

Just the same as No. I with the addition of o.io gram of salicy-
lic acid, o.io gram of coffee and o.io gram of tea.

These were placed in the incubator and kept for six hours at
105 F. and frequently shaken. The results are most interesting.

In flask No. 5 the coagulated egg albumen dissolved first ; that
in No. I was second; No. VI was third with just a few flakes un-
dissolved; No. II was fourth; No. IV was not complete; and No.
Ill was decidedly retarded, fully half of the egg remained undi-
gested. No. VI was the most interesting from the fact that it con-
tained three substances which are claimed to retard digestion. This
flask contained coffee, tea and salicylic acid and complete digestion
of the egg albumen followed the typical experiment represented in
flask No. I. It can be explained in but one way i. e., that the
small quantity of salicylic acid used acted as a stimulant.

Flask No. V, containing the absolute alcohol, was the first to
complete the digestion of the egg albumen, and we must conclude
that a very small per cent of alcohol stimulates digestion, while we
know that when the per cent is increased to 3 it greatly retards di-
gestion. (Buchner, Arch. f. Klin. Mecl. XXIX-537.)

PRESERVATIVES. 249

We find that salicylic acid in minute quantities stimulates di-
gestion. This is true of all acids. (Oppenheimer Ferments and
Their Action, page 97.)

In the proportion of I to 500 it retards digestion slightly, just
about as much as common salt, and in larger amounts it will pos-
sibly interfere with digestion. The conclusion to be drawn is that
the amount of any substance is a very important factor in deter-
mining its action on digestive processes. Certain quantities may
be positively beneficial, while increased amounts may be injurious.

FEEDING PRESERVATIVES TO ANIMALS, POST MORTEM, AND PATHO-
LOGICAL ANALYSES OF INTERNAL ORGANS.

One of the arguments advanced by the opponents of food pre-
servatives is the opinion of many eminent physicians that the deli-
cate mucous membrane of the stomach will become irritated and
inflamed, and thereby be injured to a greater or less degree, if pre-
servatives, and particularly salicylic acid, be taken continuously in
food and drink. This objection, although founded as we believe
on nothing but mere speculation, would seem to be a very strong
one indeed. We all know how easily the stomach responds to the
action of chemicals and even to the influence of the mind. The
cells of the mucous membrane are very sensitive to any influence
not exactly in accord with normal conditions. Even the state of
the nerves of the body has an influence ; nauseating odors and dis-
gusting sights are influences which completely upset the stomach.
Anger, passion, joy, sorrow and other influences of the mind act
upon the cells of the mucous membrane, and for a time the stomach
cannot perform its work normally. We all know that certain
drugs, medicines and improper food will cause stomach derange-
ment for a certain time; some medicines completely upset the nor-
mal condition, others stimulate the action of the enzymes, and still
others cause inflammation of the stomach. Some physicians say,
then, it is a very probable conclusion that preservatives will irritate
the stomach, and this argument above all others is made to do duty
as a strong reason why these chemicals should not be permitted in
foods. There are a number of cases on record where persons have
purposely taken various quantities of one preservative or another
in daily doses, and we have very favorable testimony to the effect
that no evil results followed, although in many cases abnormal
amounts were taken. When abnormal quantities of salicylic acid
are taken the warning is sounded by a ringing or buzzing sensation
in the ears, similar to the effects felt after taking quinine in large
doses. It is a remarkable fact that no discomfort has been felt from
taking stated quantities of salicylic acid below the amount which
will cause a ringing sensation in the ears.

250

CANNING AND PRESERVING OF FOOD PRODUCTS.

Diligent search has been made for the names of any persons
who would give evidence that they had experienced any ill effects
from stated doses of salicylic acid under the amount that will cause
the ringing sensation or fullness in the head. No such amount of
this preservative is ever used in food products. There are only
three or four products which require more than i.iooo of any pre-
servative, and this amount is very small in proportion to the full
meal. Such condiments as require a preservative are used only
sparingly at meal time; as a rule they are used to improve other
food or make it more palatable. No one would make an entire meal

Plate 70. Four Guinea Pigs selected as controls.

Plate 71. Six Guinea Pigs and Two Rabbits.

Whose food was saturated with salicylic acid.

of tomato catsup or chili-sauce; only a small quantity is taken on
cold meat, on oysters or in soup. Very few persons would use
these condiments at more than one, possibly two meals per day, con-
sequently the amount of such preservative as is used to keep them
in an unfermented condition would be very small indeed.

We have heard several authorities say that if preservatives
were used only in such food as we have specified there would pos-
sibly be very little objection to them, but the claim is made that per-
haps nearly all the prepared food of various kinds contained pre-

PRESERVATIVES. 251

servatives, and in such amounts would prove dangerous and poison-
ous to the human organism; also that if preservatives were per-
mitted in one kind of food it would be difficult to draw the line and
prevent their employment in all foods. Then the argument fol-
lows that in such amounts they would injure the mucous membrane
of the stomach and other internal organs.

It is easy to assume that certain effects will follow certain
causes, but it is a very difficult matter to disprove the assumption,
so when a large number of physicians assert positively that the muc-
ous membrane of the stomach will be injured by salicylic acid in
the amounts ordinarily used in food products, the amount of work
required to overthrow such an assumption is large, and the technique
employed in conducting the experiments is difficult, requiring special
skill and a thorough knowledge of pathology. To this end a series
of experiments were conducted with animals, and Dr. W. H. In-
gram, professor of pathology in the West Penn Medical College,
and Dr. R. G. Burns, pathologist and bacteriologist for the City of
Allegheny, Pa., undertook the pathological part of the work. A
number of guinea pigs were fed a weighed amount of salicylic acid
daily. The acid used was the synthetical product, that which has
been used so extensively in food. 7^2 milligrams of the acid were
mixed in a breakfast cereal with milk, which amount was fed daily
to each pig. This amount was found too large because the ani-
mals would not eat it unless forced to do so by hunger, so the
amount was cut down to 5 milligrams. The only food taken by
the pigs outside of the prescribed diet was grass, which was fed to
them liberally. Comparing the weight of a guinea pig with that
of an average man, which is as i to 100 or i to 150, the same pro-
portion of acid would be from 7J4 to 10 grains daily for a man, and
this amount of preservative would be sufficient to inhibit the growth
of micro-organisms in 16 to 24 ounces of solid food in proportion of
i to 1000. This amount of preservative is far in excess of the
amount taken in food daily by any person, but it represents an ex-
treme case, but nevertheless one which might be possible. It is
possible that in rare cases a person might consume such a quantity
of certain foods and drinks that he would take as much as 10 grains
or more in a single day, but this would not be continued daily.
Physicians prescribe sodium salicylate in 30 grain doses three times
daily for rheumatism. In this there would be about 22 grains of
pure salicylic acid in each dose, consequently 60 grains daily for a
limited time would not endanger a person. Therefore, if any per-
son should happen to take more than 10 grains at a single meal or
in one day, he would not suffer any special inconvenience.

We are certain that the experiment conducted with the guinea
pigs on a basis of 5 milligrams of salicylic acid daily is sufficiently
broad to cover all cases.

252 CANNING AND PRESERVING OF FOOD PRODUCTS.

The experiments were conducted with guinea pigs in prefer-
ence to any other animals for several reasons. There are no ani-
mals which live on a diet exactly the same as a human, and in select-
ing animals we must not select any such as the dog or cat which eat
food partially decomposed, because the stomachs of such animals
are not as sensative to poisons as the human. The stomach of the
guinea pig is sensitive to poisons and cannot tolerate certain foods.
Even milk is not properly digested unless mixe