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HANDLI

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G APPLES

U. S$. DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C.

Iscmenpnucush 1942 22° | sRRevised October 1951 |

Historic, archived document

Do not assume content reflects current
scientific knowledge, policies, or practices.

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cae

aly:

Circular No. 659

Issued mxgust 1942) Wachinecon 1 C.
Revised October 1951

UNITED STATES DEPARTMENT OF AGRICULTURE

Handling Apples From Tree to Table

By D. F. Fisuerr, formerly principal horticulturist,! and Epwin Smita, senior horticul-
turist, Division of Handling, Transportation, and Storage of Horticultural Crops,
Bureau of Plant Industry, Soils, and Agricultural Engineering, Agricultural Re-
search Administration

CONTENTS

Page Page

introductions 2h. oA Se 1| Factors affecting condition during

The grower’s responsibility ________- 2 storage—Continued

When to pick apples___*__-___- 2 Fungus diseases____________-_- 15

Criteniavof- maturity == 22222 - = 3 Bruising and other mechanical
Wihenato-pack appless === 30 iro 0. - 6 TURES 2 2 ec a ee Nee 18
Factors affecting condition during Physiological diseases______--_-_- 22
storage_--__---------------- © Wftects of packaging--.22-2.-< =-- 26
Maturity at harvest___---____- 8 Prepackaging for the consumer__ 33
Storage temperature ___-_-____- 9 | The shipper’s responsibility________- 35
(Hess SDE ea ST Sree a ear OE The dealer’s responsibility 37

Atmospheric humidity - - ------- aa ae Saas Soran
Storage with other products._.._ 15| Phe industry’s responsibility -__----- 41
ANTE PUTINCAMONS == 22-25-22 2= 2 i> Biterature cited xe sae sees = ee 42

INTRODUCTION

The condition of apples in retail markets is sometimes disappointing
to buyers. To the extent that it influences the demand for apples, such
disappointment affects the market price of the fruit and the returns to
the grower. Most important in this connection are the stage of ripeness
of the fruit and its freedom from decay, bruises, and other injuries.

Growers who invest a season’s work in pruning, fertilizing, spraying,
and cultivating their orchards, with all the care and expense necessary
to produce a clean crop of high-quality fruit, cannot help being dis-
turbed by the poor condition of apples offered by retailers. This also
constitutes one of the greatest handicaps to success of organizations
established by the apple industry to advertise and otherwise promote
the sale and use of apples.

1 Died September 18, 1949.

2 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

Growers are inclined to place the blame for the lack of quality-in the
apples offered in grocery stores and other outlets on the retailers and
other intermediaries in the merchandising chain. They feel that the
handlers of the fruit are not ‘‘apple-minded’’; that to them apples are
just so much perishable merchandise to be handled and priced according
to the risk attached; that, in the absence of knowledge on how to mini-
mize the risks, the retail price of the fruit is often pyramided to a point
at which sales are retarded and the whole industry suffers correspond-
ingly; and that, consequently, customers, unable to buy the kind of
apples that they would like, turn to competing fruits.

Market men, on the other hand, hold that frequently the fruit when
received has already deteriorated so much that its value is greatly re-
duced and the hazards of further deterioration while in process of sale
are greatly increased.. Most retailers are no more interested in apples
than in any other commodity that will yield the same profit; so, if there
are unusual risks in handling apples, this fruit naturally will not receive
the consideration that it otherwise would. 3

This circular gives the available information on how to handle apples
from the time of harvest so that they will reach the ultimate consumer in
prime condition, as well as the reasons for the reeommendations.. Need
for this information is greater today than it was a few years ago, because
of the increased production of apple varieties that are more susceptible
to injury and deterioration during storage, transportation, and market
distribution than many of the varieties formerly grown. Approximately
60 percent of the commercial apple production of the United States now
consists of varieties having relatively soft flesh. Such important varie-
ties as McIntosh, Golden Delicious, Cortland, Stayman Winesap, and
Delicious and its red strains all are much more tender and more subject
to injury in handling than are the hard-fleshed varieties like Winesap,
Yellow Newtown, Baldwin, and York Imperial. While all varieties
should be handled carefully, it is particularly important with the tender-
fleshed varieties. .

THE GROWER’S RESPONSIBILITY

In the business of placing good-quality fruit before the consumer it is
the responsibility of the producer to grow a crop of good apples, rather
than just a good crop of apples. It is axiomatic that the orchard must
be properly pruned, sprayed, and cultivated to produce a profitable
crop. Every successful orchardist, although alert for new ideas in apple
culture, is already familiar with good cultural practices and is producing
a certain proportion of good apples. Progressive growers constantly
strive to increase the proportion of good apples as well'as to increase the
- gize of the ercp.

WHEN TO Pick APPLES

One of the principal causes of the poor condition of apples as they
finally reach the consumer is failure to pick them at the proper stage of
maturity. When picked too soon, apples fail to develop good eating
quality ‘and are very susceptible to certain functional diseases that de-
velop later, particularly bitter pit and scald. When not picked soon
enough, they do not stand up well in storage and are subject to other
functional diseases that often cause serious losses in storage, especially

HANDLING APPLES FROM TREE TO TABLE S

soft scald and internal breakdown. The reason for the failures is that
the apple is a living organism with a more.or less definite potential
span of life. If it lives too fast, either before or after picking, its vitality
_ is exhausted prematurely, and the time it remains in good eating condi-
tion is shortened proportionately.

While attached. to the tree the apple is part of the tree and is in-
fluenced by any factors that affect the growth of the tree. When the
tree suffers from drought, for example, the apple responds by slowing
down its rate of growth; when the tree is so stimulated that it makes
abnormally fast growth, the fruit grows vigorously and may become
overgrown and punky. As the fruit grows it accumulates the constit-
uents which finally characterize a mature apple. Not all of the constituents
are accumulated at the same rate; only at maturity is the final balance
_reached. As the apple grows the fleshy part becomes essentially a reser-
voir for the materials upon which its potential storage life depends.
These are chiefly carbohydrates, malic acid, water, small amounts of
aromatic materials highly important in giving flavor, and vitamins and
minerals important for dietetic value. As the apple approaches maturity
it continues to increase in size but loses acidity and increases in sweet-
ness, with the conversion of starch into sugar. Ripening may occur
either before or after harvest and is accompanied by a softening of the
flesh and an increase in juiciness and aroma.

A relatively small proportion of the sugar in the apple is used in res-
piration, being broken -down to carbon dioxide and water, which are
given off to the atmosphere. The acidity is, however, reduced to a much
greater extent during ripening than is the sugar; and, in addition, the
aromatic materials are gradually lost by volatilization. The taste be-
comes progressively more insipid and less desirable as the apple is held
beyond its normal storage season. Everyone knows that if an apple is
left on the tree or held in storage too long it becomes mealy, flavorless,
and soft. When the life processes of the fruit are carried so far that

pectic materials finally dissolve out of the cell walls, permitting the cells
to separate easily, the mealiness that characterizes overripe apples
is produced. What remains at the end is an apple in the last stages of
senility, entirely unsuitable for market and undesirable for either culi-
nary or dessert use. Therefore, although the fruit must become mature
before harvest to develop best quality, the ripening for the most part
should come after harvest to insure long storage and good market
quality.

CRITERIA OF MATURITY

Criteria of maturity for apples have included ease of separation of
the fruit from the spur, fruit color and appearance, period from full
bloom, firmness of the fruit, and certain tissue characteristics (9).?
None of these is entirely dependable under all conditions.

EASE OF SEPARATION FROM THE SPUR

When an apple is ready to pick, it can be separated from the spur
without breaking the stem merely by lifting it in the hand with or with-
out a slight rotating movement. As the attachment of the fruit to the

2 Italic numbers in parentheses refer to Literature Cited, p. 42.

= CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

spur is like a hinge, picking should be an unhinging process. Inexperi-
enced or careless pickers, however, often pull the fruit from its attach-
ment. This usually results in breaking the spurs, which cuts down the
bearing surface and reduces succeeding crops, or in pulling out the stem
of the apple and tearing the flesh, thus opening the way to decay.

Ease of separation is not a reliable index of maturity (10). Under
some conditions apples start to drop before they are properly mature.
Then they may be harvested before becoming sufficiently mature to
develop the best quality after ripening. Harvest sprays, such as naph-
thaleneacetic acid, which have come into rather general use to prevent
fruit drop in some sections (1), invalidate the ease of separation from
the spur as a criterion of maturity. Although these sprays make the
fruit stay on the tree longer, they do not interrupt the advance of ma- -
turity; and as a result of their use picking may be delayed until the
fruit is overmature.

FRUIT COLOR AND APPEARANCE

The blush, or red color, of an apple is not a reliable index of maturity.
The ground color (underlying green or yellow), however, can be used as
an index. The quality of a red apple can be judged ordinarily by the
proportion of red to green; the more red, the better the eating quality.
As most varieties of “apples become mature the ground color changes
from a green very much like that of the leaves to a lighter shade and
eventually to yellowish. The time to pick most varieties is when the
first signs of yellowing appear (9). This is not always true with some
varieties—Grimes Golden, Jonathan, and Yellow Newtown, for example
—when grown under certain conditions. The red sports of some varieties
usually become fully red before they are mature, with no underlying
ground color left for observation. As a result, they have frequently
been picked too soon and have suffered in popular esteem because they
were judged to have poorer quality than the parent variety. Although
ground color cannot be used as an index of maturity for red bud sports,
the ground color of the parent varieties growing in the same vicinity
can be so used, as their seasons of maturity are ordinarily about the
same.

As fruit matures on the tree it develops a waxy coating and the lenti-
cels, or pores in the skin, become sealed with cork. These changes,
however, are not sufficiently discernible with most varieties to make
them of muchevalue in determining when the fruit should be picked.

PERIOD FROM FULL BLOOM TO MATURITY

The number of days from full bloom to picking maturity has been
found to be rather constant over a wide range of climatic and cultural
conditions, hence very helpful in determining when the crop should be
picked (10). The method requires the keeping of records showing the
dates of full bloom of varieties in a given orchard. This is the date when
the first petals fall without the influence of strong wind, or when most
of the basal blossoms in a cluster have opened. W hen warm weather
that brings the center, or king, blossom into full bloom is followed by
cool weather that retards the opening and pollinating of the other blos-
soms for a week or more, establishing the date of full bloom for most

HANDLING APPLES FROM TREE TO TABLE 5

of tue fruit that sets is subject to error. The time of maturity of dif-
ferent fruits on the same tree may vary decidedly.

The number of days from full bloom to maturity for the varieties
- on which a long-time study has been made in different sections of the
United States (10) is shown in figure 1. The middle part of each bar

MATURITY
EARLY OPTIMUM LATE

VARIETY

WILLIAMS EARLY RED__ Sama

RACIINIGOS Heteme feces On ee oe ee ook

ATOINVAMIA Neer sc rosie oe tane o S oe eee ae
GRIMESHGOLLDEN sss see rs ot ee ee ee ees

DELICIOUSH. 222s. sd STS IE yee SOU te Da EEE ee

GOMDENBDEINICIOUSte ce et a ete DS 7 Ae OS ees oa secaaccoes ESE

ViEIMCOWENE Wal OWN unseat be 08 Nie ee ecko eee _ SSE
ROMEAB EA WIL Vien see os we renee See Se Seo esac o eel eel leak SSE)
GIAVITANEWINEGA Pimento ee he es eee ek _ Se
WINES A Piermont rey ere ts ne a le
VORIGIMEE RIA Ieee tena ea a ee eos See SS

70 80 90 100 10 120 130 140 150 160 170 180
ELAPSED TIME FROM BLOOM (DAYS)

Figure 1.—Days elapsing from bloom to maturity. For meaning of different parts of
bars, see text.

_represents the period when the fruit will be at optimum maturity for
best dessert and storage qualities. Variations from these periods
occurred during certain seasons in different regions; the most obvious
reasons for them being variations in the volume of the crop, such as
light crops that mature in fewer days and heavy crops that require a
greater number of days after full bloom. In certain instances an unu-
sually early blossoming season with cool weather during the first month
thereafter was followed by a longer than average period to time of
maturity, whereas a very late blossoming season with optimum growing
~conditions thereafter has been known to shorten the period to optimum
maturity by nearly a week.

FIRMNESS AS DETERMINED BY THE PRESSURE TEST

Firmness, as indicated by the pressure test, has not been found to be
a reliable index for determining when apples acquire satisfactory ma-
turity for picking (10). Measuring firmness with the pressure tester,
however, is useful in determining when apples are becoming overmature
and too soft for storage.

As apples approach maturity they become progressively less resistant
to pressure, a characteristic which makes it possible to utilize mechanical
means of measuring the rate of softening. Several types of pressure

6 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

testers have been devised. The one most commonly used is that de
veloped by Magness and Taylor (17), which measures the pressure re-
quired to force a plunger seven-sixteenths of an inch in diameter into
the flesh of the apple to a distance of five-sixteenths of an inch after
paring off the skin. Haller (7) has presented the results of a long series
of investigations on the use of the pressure test on apples and other
fruits. Pressure-test records have been transposed into the ordinarily
accepted commercial designations of “hard,” “firm,” “firm ripe,’ and
“ripe” by Haller, Lutz, and Mallison (8). The foregoing publications
give details on the application and limitations of the pressure test.

TISSUE CHARACTERISTICS

As apples mature and ripen starch and astringent constituents de-
crease. Tests for starch with an iodine and potassium iodide solu-
tion have proved unreliable because of the variability in starch among
individual fruits of practically the same degree of maturity and because
of variability due to heavy and light crops and seasonal growing condi-
tions. Familiarity with the astringent taste of apple tissue is a guide to
picking maturity of varieties like Delicious and its red bud sports; satis-
factory maturity is not acquired until sensations from astringency are
practically absent. This is usually associated with loss of toughness
in tissue texture. Water core in.the tissue is a very important considera-
tion in determining when to pick certain varieties. Investigations by
Brooks and Fisher (4) show that water core develops first in fruit ex-
posed to direct sunshine on the south and west sides of trees. Conse-
quently, apples from these parts and the tops of trees should be examined
for water core. As maturity advances water core increases; this gen-
erally is a signal that the fruit is passing the optimum state of picking
maturity and may become subject to internal breakdown early in
storage. ;

GENERAL RECOMMENDATIONS FOR PICKING

Because no single criterion is entirely dependable for determining
when to pick, the grower usually must base his decision on a number of
factors. A tentative date on which to start picking a variety should be
established on the basis of the number of days from full bloom. As this
date approaches the fruit should be watched closely. If the fruit shows
signs of advanced maturity, such as a break in the ground color, a tend-
ency of sound fruit to drop, water core, and loss of astringency and
bitterness, the picking date should be advanced. On the other hand,
if the apples are still green in color, hard, tough or woody in texture,
and astringent or bitter in taste, it may be advisable to delay picking
‘beyond the tentative date. The date of picking will probably need to |
be advanced with a light crop or exceptionally warm weather after
bloom; conversely, a heavy crop or cold weather after bloom is likely
to delay the date of picking.

WHEN. TO PACK APPLES

Ideally, apples should be packed and stored or shipped immediately
after being picked. Danger of blue mold infection is less if this can
be done because injury to the apples during the packing operations is
much less likely if the fruit is hard than if it has begun to soften. Scald

HANDLING APPLES FROM TREE TO TABLE | <

can also be controlled much more effectively if oiled paper is applied
soon after the apples are harvested. Unless the oiled paper is applied
within a month, or 6 weeks at the most, it is ineffective in controlling
~seald. Another advantage of prompt packing is that 1t gives an oppor-
tunity to sort out the culls, which not only may be sources of infection
by rot organisms but which also take up storage space that may be
needed for marketable fruit.

Practically, however, a large part of the crop is often kept from a few
days to several months before it is packed for market. Sometimes this
delay is due to lack of packing facilities that will take care of the fruit
as fast as it is picked, and sometimes packing is intentionally postponed
or spread out. If the apples are particularly susceptible to bitter pit,
it may be advisable to delay packing for a month or 6 weeks to give the
‘disease a chance to become manifest so that affected apples can be sorted
out. When the delay is for more than a few days, the fruit is ordinarily
placed in storage and packed at the convenience of the owner. Although
this has some advantages, especially from the standpoint of spreading
labor, these are outweighed by the disadvantages. When packing houses
are congested and cold-storage space is not available, it is ordinarily pre-
ferable to leave the picked fruit in the orchard in the shade of the trees;
the boxes should be spaced so that air can circulate freely about them,
and the stacks should be covered so as to protect the fruit from direct
sunlight and rain (fig. 2). The apples will ripen less rapidly than if
stacked in the open in unprotected large piles at the packing house, as
is sometimes done (fig. 3).

Figure 2.—Boxes of apples in the shade of a tree in an orchard. The boxes are covered
to protect the fruit from direct sunlight and rain, yet the air can circulate freely
about them.

8 CIRCULAR 659, U. 8. DEPARTMENT OF AGRICULTURE

Figure 3.—Holding apples in large compact stacks outside a packing house is not
recommended. In such piles, MEE Oeics from sunlight and rain, ripening is
accelerated.

FACTORS AFFECTING CONDITION DURING STORAGE

The sequence of changes in the harvested fruit is much the same as in
apples that are allowed to remain on the tree until they become overripe,
mealy, and insipid; that is, even fruit harvested at the proper stage of
maturity eventually becomes mealy and flavorless if held too long or
under improper storage conditions. In fact, unless the fruit is placed in
cold storage promptly, the approach of senility is more rapid after the
fruit is picked than when it is left on the tree. The length of time that
apples can be held in satisfactory condition in storage depends on three
factors: (1) Maturity at Pe eet 2) storage temperature; and (3) pres-
ence of diseases.

The ee AT HarvEST

Apples picked before they are sufficiently mature generally remain
sour and astringent, even after they have ripened, and, except for the
red bud sports, are poorly colored. They have a marked tendency to
wilt or shrivel and are susceptible to scald and bitter pit during storage.

The apples most often picked before they reach the proper stage of
maturity are the solid-color varieties, such as Grimes Golden and Yellow

Newtown among the green or yellow kinds and the red bud sports of the .

Delicious. When picked at the proper stage of maturity, all these rate
among the best for dessert quality; but when picked too soon, they are
suitable only for cooking, and the Delicious is not particularly good even
for that.

When the weather remains warm at harvesttime, particularly at night,
some varieties of red apples are slow to color and there is a tendency on
the part of growers to delay picking until the apples do color, with attend-
ant danger of loss from dropping and of the fruit’s becoming too mature
for storege. Because this is particularly true of Jonathan, Delicious,

HANDLING APPLES FROM TREE TO TABLE ; )

and Rome Beauty, red bud sports of these varieties have been eagerly
sought and largely substituted wherever possible. Many large plant-
ings of the original varieties will doubtless remain in heavy production,
_ however, and will continue to pose problems of color, dropping, and
overmaturity. Use of hormone sprays, which prevent dropping of the
fruit, meets the problem of slow coloring only in part, because of the
- danger that apples thus held on the tree to color may become too far
advanced in maturity or may be fully ripe at time of picking. An early
picking of the fruit of advanced maturity so that it does not become
overmature would then be desirable. Careful sorting during packing
may also be desirable in order to remove fruit of advanced maturity, thus
maintaining the storage quality of the pack. Overmature apples are
particularly susceptible to water core, soft scald, internal breakdown,
and Jonathan spot and are more subject to stem punctures, bruising,
and other mechanical injuries through which blue mold infection takes
place. Blue mold entering through lenticels is also more likely to infect
overmature apples than those picked at proper maturity.

STORAGE TEMPERATURE

The life processes of apples that have to be considered in the successful
storagé of the fruit after harvest are essentially chemical, and, as with
other chemical processes, the rate at which they proceed depends largely
upon the temperature at which they can be carried out, that is, upon the
temperature of the applés. Apples freeze at about 28.5° F. (27); hence,
it is necessary to keep them above this temperature. In practice, stor-
age temperatures of 30° to 32° have been found most satisfactory (22).

Magness and others (16) found that the rate of respiration largely
governs the rate of ripening and softening of apples in storage. They
found that at 40° F. this rate is approximately twice as rapid as at 32°;
at 50° it is almost double that at 40°; and at 70° it is about twice as fast
as at 50°. At 30°, on the other hand, 25 percent more time is required
for apples to ripen than at 32°. These results emphasize the importance
of quickly cooling apples to the minimum safe temperature for storage;
the apples will ripen as much in 1 day at 70° as they will in 10 days at 30°,
Holding apples at 70° for only 3 days after harvest thus will cut off about
a month of their potential storage life at 30°. If 30° storage is not im-
mediately available, every opportunity should be taken to cool the fruit,
such as stacking it in the shade and providing good ventilation, especially
at night (fig. 2). The same principle applies after storage. It is therefore
inadvisable to remove from cold storage at one time more apples than
‘can be used or marketed before they deteriorate seriously. It must also
be remembered that after storage the span of life remaining for the
fruit is much shortened, and, as the end point is uncertain, the gamble
in holding at. warm temperatures is much greater.

Cooling the fruit means the transfer of heat from the fruit to the sur-
rounding air. The effectiveness of the cooling depends on the difference
between the temperature of the air and that of the fruit and the rate at
which the air moves over the fruit. In common storage, cooling is
accomplished by transferring heat from the fruit to the outside air.
_A good ventilating system intelligently operated is necessary to make
this method efficient; the vents should be opened when the outside air
temperature is lower than that of the fruit and closed when conditions

10 CIRCULAR 659, U. 8. DEPARTMENT OF AGRICULTURE

are reversed. In cold storage the heat is transferred from the air sur-
rounding the fruit to refrigerated pipes or other artificially cooled sur-
faces and eventually is transferred to the outside air by the refrigeration
system (/1).

Cooling fruit ordinarily is not a rapid process, nor is ripening checked
instantaneously when fruit is placed in cold storage. Time is needed to
remove the heat from the fruit; the rate of cooling is affected not only
by the temperature but also by the type of package, the method of pack-
ing, the quantity of warm fruit placed in the room, the manner in which
the packages are stacked, and the rate of air circulation around the fruit.
Tests were conducted at the cold-storage laboratory of the Bureau of
Plant Industry, Soils, and Agricultural Engineering, Beltsville, Md.,
to determine the influence of the type of package on the rate of cooling.
The temperature records were taken at the core of an apple at the center
of each package. The packages were not stacked and,, being freely ex-
posed on all sides, cooled faster than they would under commercial
storage. ,

The results (table 1) show that the use of liners, cushions, and paper
for packing slows the rate of cooling. Apples in an open bushel basket
just as they came from the orchard, without liners, wraps, or shredded
oiled paper, cooled from 63° to 32° F. in 18 hours, whereas fruit packed
in lined baskets with a pad under the lid and shredded oiled paper well
distributed throughout required about 10 days to cool from 70° to 32.5°.
The relative thickness of the containers doubtless had an effect on the
rate of cooling, but the size of the package, or the mass of fruit enclosed,
and the tightness of closure apparently were important factors also, as
shown by a comparison of the results for apples packed in the barrel
with those for apples in the open bushel basket. It took only 18 hours
to cool the fruit in the middle of the bushel basket from 63° to 32°, but
it took 10 days to cool that in the middle of the 3-bushel barrel from 66°
to 36°. Similar results were obtained with the apples packed in the
standard box and in the 1)s-bushel eastern crate; the packing in both

TaBLE 1.—Influence of method of packing and storing apples in unstacked
individual packages on their rate of cooling at 32° F. in still air

Temperature at core of apple in center
of package—

Package Packing material
Wh After | After | After | After | After
fee fea Sere 7 10
stored
hours | hours | hours | days | days
or °F SG ok elt Hi
Bushel-basket-2=2|9Nonete= =2. se o™ 63 AD BD a s.5 =e ee | ee
DotA ee Liner, cushion, shred-| 70 59 | 44.5 Al 33254 S220
ded oiled paper.
Barrelees 2 ssa’ None 2 ok ee ee 66 64 | 59 55 | 41 36
Standard box____| Liner, cushion, oiled 7fil 67 | 60 5ANITAT coe oe
wraps.
11%-bushel east- Linere cashiers shred-| 66 63 | 61 o9 | 54 44

ern crate. ded oiled paper.

HANDLING APPLES FROM TREE TO TABLE ell

of these containers, however, included liners and pads, as well as oiled

wraps or shredded oiled paper. The eastern crate contained 20 percent
more apples and was the tighter package; after 10 days the fruit in its
- center had cooled only 22°, while that in the standard box had cooled
34°.

The results of the tests should not be interpreted to mean that use of
pads, liners, and other packing material is undesirable, but rather that
these materials insulate the fruit and increase the requirement for re-
frigeration if properly packed apples are to be cooled as quickly as is
desirable.

In precooling apples, air at a temperature below 32° F. is used to
rapidly lower the temperature of the fruit. The greater the difference
between the temperature of the apples and that of the air, and the more
_rapid the rate of air movement, the more rapid the rate of cooling will be.
However, as the temperature of the fruit approaches that of the cooling
medium the rate drops (fig. 4).

70 :

STILL AIR; LINER, PAD, AND SHREDDED eee PAPER
STILL AIR; WITHOUT LINER, PAD, OR SHREDDED OILED PAPER

o
{o)

ta. MOVING AIR; LINER, PAD, AND SHREDDED OILED PAPER
=> = “MOVING AIR; WITHOUT LINER, PAD, OR SHREDDED OILED PAPER

TEMPERATURE (°F.)
on
(@)

0 12 24 36 48 60 72 84 96 108 120 132 144 156 168
ELAPSED TIME (HOURS)

Figure 4.—Rates of cooling of apples packed in bushel baskets and stored at 32° F.
in still and in moving air. Velocity of the moving air was approximately 200 feet
per minute. The thermometer was placed in centermost fruit in each container.

Some persons believe that when apples are cooled too rapidly the

quick change in temperature may produce shock to the fruit, with con-

- sequent ill effects. Only varieties that are susceptible to soft scald are
likely to be injured by fast cooling in storage. With other varieties
the more rapidly fruit can be cooled to the proper storage temperature,
the more quickly will deteriorating processes of ripening be arrested
and the longer the fruit can be kept in good condition.

While apples are not commercially precooled to the same extent
as are peaches, pears, plums, and certain other fruits, in many cases it
would undoubtedly be beneficial to precool them, Delicious in particular
because this variety 1s so prone to become mealy and overripe. Records

of fruit temperatures, if taken in many storages, would disclose that
most of the fruit is not cooled to 32° for several weeks after harvest. Mean-
while, the rate of ripening is being arrested only in proportion to the rate
of cooling. The slow cooling is often due to lack of sufficient refrigerating
capacity of the cold-storage plant, but it may also be due to faulty stow-
age in the room, particularly failure to leave space for air circulation
through the stacks and to spread out large receipts of warm fruit.
Records taken in packages held at 32° F. and stowed as they would
_ be in commercial practice showed that the rate of cooling was faster in
the top layers of the stacks because the air could circulate more freely
there. The apples cooled more in the first 12 hours than in the next 12
and the rate of cooling fell off progressively thereafter as the temperature

1 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

of the fruit approached that of the air in the storage room. The insulat-
ing effect of the liners, pads, and shredded oiled paper ordinarily used
is brought out in these results as well as in those in table 1. The effect
of air movement in increasing the rate of cooling is also brought out
clearly. When the rate of air movement was about 200 feet per minute,
the apples without packing material cooled to 32° in 36 hours, while
in still air they required more than 96 hours to reach this temperature.
In the baskets with lmers, pads, and shredded oiled paper similarly
packed apples required 57 hours in the air moving at 200 feet a minute
and more than 156 hours in still air.

In stacking packages in storage, adequate provision for the cold air
to reach all packages in the room is essential, not only for the rapid re-
moval of field heat but also for the continuous removal of the heat of
respiration, thereby preventing the accumulation of heat and develop-
ment of warm pockets in the storage room. ‘This is not so serious a
problem when apples are packed in bushel baskets (fig. 5) as when they
are packed in crates, boxes, and cartons. Crates, boxes, and cartons
should be spaced with from 2 to3 inches between rows of stacks, and the
rows should run in the direction of the air currents across the room.
It is especially important to provide spacing when tight, close-fitting
packages like cartons are stored; lath or other CERES strips should be
used to separate the packages in each stack.

cone §.—Method of Havin: bushel baskets of apples and staggering them by
placing each basket on the edges of those beneath to keep pressure away from cen-
ters of lids. Stacking baskets this way, instead of putting alternate baskets upside
down as is sometimes done, permits better air circulation. Workmen should never
stand or walk on the baskets.

HANDLING APPLES FROM TREE TO TABLE een be

Gas STORAGE

In England, some varieties of apples, particularly the leading cooking
variety, Bramley’s Seedling, in ordinary cold storage develop low-tem-
perature breakdown. . The same is true to a limited extent in cer-
tain parts of the United States, particularly with Yellow Newtown
apples in the Pajaro Valley, Calif., and with McIntosh in New York
State, in which brown core may develop excessively during storage at
32° F. The gas-storage method was developed by Kidd and West (12)
in England to meet this problem. The method calls for an airtight
storage chamber, in which the carbon dioxide produced in the respira-
tion of the apples is allowed to build up to the desired concentration
while the oxygen content of the storage air is reduced. The temperature
of the storage room is usually held at 40°; so refrigeration is required in
addition to the gas treatment. Because varieties differ in their response
to different. ratios of carbon dioxide to oxygen, separate chambers may
be required for different varieties. The desired ratio is obtained either
by pumping the storage air through a lye solution to absorb the excess
carbon dioxide or by ventilating the chamber periodically to admit fresh
air and build up the oxygen. As the vast bulk of the American apple
crop can be held satisfactorily in cold storage and most varieties are not
benefited by the gas treatment, it is not likely that this method of stor-
age will have wide application in this country because of the added cost
and extra work that it entails. However, for special situations it may
be utilized profitably despite the extra cost. Several gas storage rooms
have been put into operation in New York for the storage of McIntosh
apples in accordance with the recommendations of Smock and Van
Doren (26).

ATMOSPHERIC HUMIDITY

Keeping the apples from wilting and shriveling is as important as
keeping them from getting overripe. It can be done by controlling the
humidity in the storage space. A certain amount of moisture is con-
tinuously lost by the apples through the process of transpiration (evap-
oration).

Although evaporation can be cut down by reducing the temperature,
it is particularly serious in apples which are not properly matured and on
which lenticels are not normally corked over and the wax coating is not
_ sufficiently developed. The natural barrier to loss through evaporation
is the waxy skin of the fruit. Any injury to the skin or the removal of
the wax, as in some washing processes, facilitates moisture loss and in-
creases the severity of wilting. Careful handling to avoid bruising and
injury of the skin and the use of proper washing processes are important
therefore in preventing excessive wilting or shrinkage in storage, as well
as blue mold rot and other types of decay. The drier the air the greater
is the degree of wilting. If the relative humidity of the storage is main-
tained at 85 percent or higher, which is the approximate water content
of apples, the pull on the fruit for moisture, or the evaporating power
of the air, will be slight and shrinkage of the fruit will be correspondingly
lessened. Where the relative humidity of the storage air is below opti-
mum, the faster the air is moved over apples the more moisture will be

14 CIRCULAR 659, U. 8. DEPARTMENT OF AGRICULTURE

removed from the fruit; therefore, it is especially important to maintain
an optimum relative humidity in cold storages with air-circulating sys-
tems, especially when fruit is stored in orchard crates or boxes. Observa-
tions in commercial cold-storage plants have shown that the relative
humidity in the apple-storage rooms is frequently less than 85 percent,

sometimes as low as 70 percent.

To maintain desirable humidity conditions so as to reduce wilting,
it is well to fill the storage rooms, thus reducing as much as possible the
ratio of air to fruit.

In designing a cold-storage plant it must be remembered that most of
the moisture producing frost on the coils or diluting the brine used in a
brine-spray chamber during the storage period comes from the fruit.
The greater the temperature difference between the air and the cooling ~
medium, whether it be coil surface or brine spray, the more rapid the
condensation of moisture and the greater the drying effect on the at-
mosphere, thus increasing the pull on the fruit and causing wilting.
Use of a brine spray in an air-circulating system is no insurance against
low relative humidity; it will have the reverse effect if the temperature
of the brine is greatly below that of the air. Consequently, it is essential
that there be enough coil capacity, or enough coil capacity plus volume
of brine spray, to provide the desired refrigeration without the cooling
medium being more than 7° or 8° F. below the air temperature of the
room (11). The adequacy of thé building’s insulation may play an im-
portant part in preventing shrivel in fruit, because the better the insula-
tion the less difference there will be between the temperature of the air
and that of the cooling medium.

It is difficult to raise the humidity in a cold-storage room kept within
the most desirable temperature range for apples, 30° to 32° F., because
the moisture 1s so quickly condensed and frozen. However, if it be-
comes necessary to raise the humidity, it can be done best by using a
humidifying apparatus that introduces steam into the air of the storage
room. A simple humidifier of this type can be made by placing a shallow
pan of water on some strip heaters, operation of which is controlled
through a humidistat. An electric fan should be arranged to blow over
the surface of the water. The efficiency of the apparatus can be in-
creased somewhat if absorbent toweling is looped into the water from a
series of parallel supports placed 8 to 10 inches above the surface of the
water. In this arrangement the air current from the fan should pass
through the loops of the wicking. Adding moisture to raise the humidity
by any method is only an expedient, not the most satisfactory method
of controlling wilting and shrinkage. All that can be accomplished by
evaporating moisture into the storage air is to meet some of the moisture
" requirement of the air rather than to permit it all to be taken from the
apples. The moisture requirement of the air cannot be satisfied so long
as the temperature of the cooling surfaces remains markedly below that
of the air.

Other measures used to some extent to avoid the wilting effects of
dry atmospheres are the coating of apples with wax or packing them in
packages having moistureproof liners. These expedients have to be used
with a degree of caution, as there is danger of sealing the apples too well.
in which case the oxygen within the fruit is reduced to a point where the
fruit cannot respire normally; this results in development of undesirable

HANDLING APPLES FROM TREE TO TABLE Sama 3)

flavors, sometimes in tissue breakdown. In apple waxing care must be
taken to see that the wax used, or the thickness of its application, will
not greatly interfere with normal respiration. If the apples are packed
in consumer units of Pliofilm or similar transparent film, provision for
gas exchange is necessary. If the package is sealed by heat or stapling,
perforation of the film is essential to allow sufficient oxygen to reach the
fruit. Such perforations are not necessary if incomplete closures, such
as the “‘snap sack,”’ are used. Such openings do not seriously reduce the
effectiveness of the film in protecting the fruit against moisture loss.

STORAGE WITH OTHER PRODUCTS

Apples absorb odors very readily; it is therefore undesirable to store
- them with other products that have pronounced odors. This is particu-
larly true of potatoes and other root crops, which often give apples an
earthy flavor. As apples give off ethylene, a gas that stimulates respira-
tion and ripening, the potential keeping quality of other products stored
with apples may be adversely affected. This is particularly true of cut
flowers, which may be made to shed their petals or are otherwise injured
by ethylene (28).

AiR PURIFICATION

Recirculation of storage air through activated coconut shell charcoal
has been suggested as a means of removing odors and the products of
fruit respiration from the atmosphere in apple storages (25). This is an
effective means of adsorbing odors until the adsorptive capacity of the
charcoal filters is reached, whereupon it is necessary to replace the char-
coal with a fresh charge. It has been found (6) that, although this ma-
terial removes odors, it is relatively ineffective in removing ethylene, a
product given off by ripening apples that stimulates the ripening proc-
esses in fruits. Air purification with activated charcoal removes volatile
- products other than ethylene sufficiently to reduce the intensity of apple
scald, but it does not prevent scald as effectively as oiled paper. Ozone
in apple storage removes odors and controls surface molds on packages
and walls, but does not reduce decay or control scald (22a).

FuNcGus DISEASES

Many fungus diseases of apples can cause serious losses under certain
_ conditions. Fortunately, however, most of them are primarily orchard
diseases and are controlled on the harvested fruit by the sprays that
growers apply to control them in the orchard. However, if they are
present on the stored fruit, they respond to storage temperatures about
the same as do the physiological processes of the fruit (p. 9). All
develop rapidly and are most destructive at higher temperatures; at 30°
to 32° F. many will not develop at all, or at the most very slowly, particu-
larly if the apples are not ripe. The spores of most rot organisms will
not germinate at 30° to 32°, but if infection is already present when
apples reach this temperature, most of the rots will persist during stor-
age and the causal organism will resume growth after the fruit is re-
moved toa warm place. Detailed information on the diseases of apples
in storage is given in other publications of the United States Department
947960—-51—3

16 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

of Agriculture (3, 20). Discussion here is limited to a relatively few
diseases that are especially influenced by harvesting, handling, and
storage operations; most of them are not due to fungi but are functional
or physiological in nature. —
The storage disease responsible for most of the decay in apples afte

harvest is blue mold rot, caused by the fungus Penicillium expansum
Link. It is primarily a wound parasite and ordinarily some kind of
mechanical injury must be present before the fungus can infect an apple.
This rot is very soft and watery and has a pronounced musty odor. . It”
gets its name from the bluish masses of spores that appear on the surface
of affected areas (fig. 6, A). This fungus is omnipresent wherever apples
are grown, and its spores are found in large numbers on the surfaces
of apples as they are picked and brought in for packing. As the fungus
is ordinarily incapable of penetrating the sound, uninjured skin of the
apple, careful handling of the fruit at all times is a prime requisite in

a eens pas pocorn a

ae =

Ficure 6.—A, Blue mold rot, which is soft and watery, has a pronounced musty odor
and frequently is covered with bluish masses or spores. B, Very slight bruises,
which Show prominently on a peeled apple, emphasize need for careful handling
at all times to keep the apples from being bruised. C, Bitter pit, which appears as
brownish spongy or corky spots or pits in the flesh just under the skin and usually
is most prevalent on the blossom end. D, Jonathan spot, a superficial skin disease
that gives the apple a freckled appearance.

HANDLING APPLES FROM TREE TO TABLE 7

preventing infection. Bruising and other mechanical injuries lead to
blue mold infection.

Although blue mold enters apples most often through mechanical
injuries, it sometimes enters through open lenticels in the skin; through
the stem, especially when this is enlarged or fleshy and has been broken
or injured; and also through dead calyx lobes resulting from spray in-
jury, washing injury, or other causes. Infection is more likely to occur
in ripe apples than in those that are still hard; also it is most likely to
occur at points of contact with other apples. When apples are washed
the spores of decay organisms, especially blue mold, accumulate in the
washing solutions and infection through both mechanical injuries and
open lenticels is increased. ‘The spore load of the washing solution
should be kept as low as possible by sorting out rotten apples before
washing, by careful handling to avoid injuries, by periodic renewal of
the washing solution, and, where possible, by the use of a copious fresh
water rinse. English (5) found sodium chlororthophenylphenate could
be used effectively in washing tanks to kill the spores of blue and gray
molds and greatly reduce rots caused by these organisms. This chemical
is used extensively in the Pacific Northwest in washing apples and
pears, and suggestions for its use have been published by the Oregon
Agricultural Experiment Station (73).

In cutting down the loss from blue mold rot good sanitation in and
around the packing house and storage rooms is important. As culls
are potential sources of-infection for other fruit, they should be stacked
outside the packing house and disposed of to byproduct plants or other-
wise at frequent intervals (fig. 7). Storage rooms should be kept clean
and sanitary at all times, and before each season’s use, they should be
whitewashed, well disinfected, or otherwise thoroughly cleaned and
aired. Whitewashing is simpler and generally preferable to other meas-
ures that can be taken. Adding copper sulfate increases somewhat the

Figure 7.—Hauling cull apples from the packing house. Frequent disposal of culls
reduces sources of infection by decay fungi.

18 CIRCULAR 659, U. 8S. DEPARTMENT OF AGRICULTURE

disinfectant properties of whitewash, but from a practical standpoint
this is of questionable value. It is especially desirable, however, to
clean and disinfect the floor, which is not whitewashed. Thorough
scrubbing with water containing about 0.5 percent sodium hypochlorite
and a suitable wetting agent is recommended. A number of commercial
preparations on the market are suitable for the purpose.

For disinfection, sulfur dioxide, the gas produced by burning sulfur,
can be used. The proportion ordinarily used is 1 pound of sulfur to
1,000 cubic feet of space. It should be burned in a metal vessel placed
on bricks or otherwise held off the floor. All openings should be kept
tightly closed for an hour or so.in order to permit utilization of the maxi-
mum concentration of sulfur dioxide. Sulfur dioxide is most effective
when floors are sprinkled to create a moist atmosphere; as this increases
its corrosive effect on metals it is reeommended that motors within the
room be tightly wrapped with waterproof paper to prevent possible
injury. Ordinarily formaldehyde candles can likewise be burned as in
household disinfection, but formaldehyde is less satisfactory than sulfur
dioxide because of the persistence of the odor, and thorough airing out
for a considerable period afterward is required. .

Caution.—Both sulfur dioxide and formaldehyde are toxic and in-
jurious to apples, and no fruit should be placed in the rooms until all
traces of gas have disappeared. They are likewise strong irritants to
eyes and mucous membranes. Care must be exercised to avoid contact
with the fumes during or after fumigation. Doors or windows should be
opened to air the rooms thoroughly after fumigation and before they are
entered by workmen. It is feasible therefore to fumigate only during
the season when the storage space is not in use. |

BRUISING AND OTHER MECHANICAL INJURIES |

The importance of bruising and other mechanical injuries in blue
mold infection emphasizes the need for preventing such injuries.
Pickers, sorters, and packers should wear gloves or trim their fingernails
closely to prevent fingernail punctures. All sand, splinters, and pro-
jecting nails in the fruit boxes or baskets should be removed. Pickers
should be provided with containers having rigid sides, rather than with
picking bags (fig. 8), to prevent bruising the apples when the picker leans
against the container, as he often does in picking from a ladder or in the
tree. Pickers should empty the fruit carefully into the field boxes. They
should never drop apples more than an inch or two. Field boxes should
be filled less than level full, in order to prevent bruising the fruit when
stacked (fig. 9), and care should be exercised in lidding the market pack-
ages to prevent cuts or bruises in the fruit. Use of adequate grading and
sizing machinery, which moves the fruit gently on belts or rollers, is an
important factor in the reduction of bruising damage (fig. 10). Bad
bruising often results from lack of adequate precautions in handling the
fruit in the packing house, particularly when the fruit is dumped into
the washing or sizing machinery. If it is poured out of the field crates
and allawed to drop or if it is poured or rolled around in large piles, it is
likely to be bruised and stem-punctured. Unless the apple-handling
machinery is properly adjusted bruising may also occur.

A certain amount of bruising during packing and handling probably is
inevitable, but most of the serious damage can be eliminated by careful

HANDLING APPLES FROM TREE TO TABLE 19

Ficure 8.—Buckets are preferable to picking bags, because they afford more protec-

~ tion against bruising and stem punctures. In emptying, the containers should be
lowered to bottom of the field box so that the apples will slip out gently. The boxes
should not be filled so full that they cannot be stacked without injuring the apples,
as would happen with the improperly filled box shown here.

handling, which, in turn, can ordinarily be obtained only by adequate
supervision and the use of proper equipment.

In a study of picking bruises made in Washington orchards (24) the
number of punctures, bruises, and pulled stems was recorded
periodically. It was shown that where an orchardist adequately super-
vised the work of his pickers, there were 37 bruises per 100 apples, of

20 CIRCULAR 659, U. 8. DEPARTMENT OF AGRICULTURE

FicurE 9.—Field boxes properly filled and stacked to prevent damage to the fruit
and to facilitate cooling on the receiving platform of a packing house.

which only 2 were severe; and where the work of pickers was not care-
fully supervised, there were 398 bruises per 100 apples, of which 14 were
severe. One cooperative association employed a man full time to in-
spect samples of every load received; his reports on injuries found were
promptly sent back to the orchard. As a result, the orchardist’s atten-
tion was called to bad workmanship, and picking bruises became notice-
ably low. _ Examinations of picking bruises in several orchards where
metal picking buckets with canvas bottoms were used showed (23) an
average of 1 severe bruise per 100 fruits; whereas in orchards where can-
vas bags were used there was an average of 3.75.

The use of pallets and fork-lift trucks for hauling and handling ae
before packing is being adopted in some growing sections to save time
and labor in receiving, stacking, and handling at the packing house.
Studies conducted in Washington orchards (23) show that the more
gentle and fewer handlings resulting from use of this method produce
substantially fewer bruises (table 2). In these studies a severe bruise
was considered to be a marked blemish to the appearance of the fruit
and wa’ generally at least one-half inch in diameter. The slight bruises
recorded would not be discriminated against on the market, but they
show up rather prominently when an apple is peeled. Slight bruises
are also a decay hazard when caused before the washing process; even a

HANDLING APPLES FROM TREE TO TABLE 21

PiGURE 10.~Use of adequate grading and sizing machinery, an important factor in
the reduction of bruising. All the sorters should wear gloves.

slight bruise may disorganize the cell structure at the base of lenticels
sufficiently to provide a microscopic opening for entrance of decay
organisms during washing and packing. Skin-punctured apples are
generally regarded as culls, because it is well known that they are likely

TABLE 2.—Comparison of injuries incurred by two methods of handling
unpacked apples }

|
Injuries caused per 100 fruits

. Fruits ea cepae
Handling method enna Bruises

Skin

punctures

Severe | Slight | Total

Number | Number | Number | Number | Number
Hauling from orchard:

By individual boxes__-_------ 9 ,309 jee Bee: 37.4 40.7

Onzpalletsessis ee ot ve 9,278 Al Y 6.8 lll
Storing prior to packing:

By indivadual boxes. == _—__- 3,972 0 8.8 43.4 52.2

Omnppallets eee fet 3,152 0 5.9 26.3 32.2

1 From 1948 studies with Delicious apples in Washington.
2 Careless handling with fork-lift trucks.

D2? CIRCULAR 659, U. 8S. DEPARTMENT OF AGRICULTURE

to become infected with blue mold and in consequence are only suitable
for immediate consumption. It is not so commonly recognized that
apples with severe bruises should be culled out. Bad bruises not only
detract from the sales appeal of the fruit but are also potential avenues
of blue mold infection to almost the same extent as are skin punctures.

PHYSIOLOGICAL DISEASES

BITTER PUT

Bitter pit, Baldwin spot, or stippin, as it is variously called, is a
physiological disease found all over the world where apples are grown.
It appears as brownish spongy or corky spots or pits in the flesh just
under the skin and usually is most prevalent at the blossom end (fig. 6,
C). Occasionally the pits are deep-seated and are not evident without
cutting the apple. The affected part often has a somewhat bitter taste,
which accounts for the name. Bitter pit does not impair the keeping
quality of the apples, but, because the affected parts have to be pared
away, it reduces the value of the fruit, and, of course, detracts from its
appearance. 3

No variety is entirely immune, but bitter pit is particularly prevalent
in Baldwin, Gravenstein, Arkansas (Mammoth Black Twig), Delicious,
Yellow Newtown, Rhode Island Greening, and Northern Spy. The
disease is most likely to occur in light-crop years, and apples grown on
young trees are particularly susceptible. Susceptibility to the disease
is also increased when late-season growth is stimulated by heavy irriga-
tion or rains, fertilization, heavy pruning, or other means. Bitter pit
may begin to appear before the apples are picked and seems to develop
to the greatest extent if they are picked before they reach proper ma-
turity, but as the disease is seldom fully manifested by the time of har-
vest it is impossible at that time to sort out all of the apples which will
show the pitting. Ordinarily, however, the diseased apples can be de-
tected within a month or 6 weeks after they are picked, and if susceptible
crops are held until then before sorting and packing the pitted fruit can
be eliminated. If this procedure were more generally followed, there
would be less likelihood of having to repack affected lots or suffer heavy
market losses because of bitter pit.

JONATHAN SPOT

Jonathan spot is a superficial skin disease characterized by small
black or brown spots resembling freckles scattered over the apple, par-
ticularly on the well-colored part (fig. 6, D). In later stages these spots
may become sunken and the flesh immediately beneath becomes brown
and spongy as the tissue dries out. The disease affects the appearance
and sales value of the fruit rather than its keeping quality. Jonathans
are very susceptible, but the disease occurs also on many other varieties.
The same kind of spot or one closely resembling it often seriously de-
tracts from the appearance of Rome Beauty apples. Jonathan spot is
only skin deep except in late stages, when underlying flesh tissue be-
comes brown and dried.

HANDLING APPLES FROM TREE TO TABLE e235

Jonathan spot is a physiological or functional trouble. It occurs to
some extent on highly colored apples left on the tree until they become
overripe, but primarily it is a storage disease that is most serious on
apples held in warm places. Ordinarily its presence is an indication that
the apples are ripe or well advanced toward full ripeness and that their
further storage life is not long. It can be prevented almost entirely by
picking the apples at the proper stage of maturity and storing them
promptly at a temperature of 30° to 32° F. The greater the delay in
reaching cold storage the more serious the disease. Storage at tempera-
tures higher than 30° to 32° tends to increase the severity of the disease.

WATER CORE

Water core is a functional disease that appears in the apples before
harvest and gives the flesh a water-soaked, or glassy, appearance, re-

Figure 11.—A, Water core, characterized by a glassy, or water-soaked, appearance
of the flesh around the core or main vascular bundles. Such affected apples are pre-
disposed to internal breakdown. 8B, Internal breakdown, characterized by a general
mealiness and brownish discoloration of the flesh. @ Soft scald, which makes apples
look as if they might have been rolled on a hot stove. D, Sogey breakdown, which
is brought about by causes similar to those which produce ‘soft scald.

947960—51—4

24 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

sulting from the gorging of the tissues and intercellular spaces with sap
(fig. 11, A). Because it usually becomes worse as the apples reach ma-
turity, its appearance sometimes causes growers to pick the fruit: earlier
than would otherwise be desirable. It is usually most severe on the
highly colored and most exposed apples in the tops of the trees; the
poorly colored, shaded fruit may be entirely free.

When water core extends to the skin of the apple it is easily detectable
and such fruit is seldom packed. However, it is often hard to detect
slight water core, especially if it does not extend to the skin. Conse-
quently affected apples sometimes are stored unintentionally. Growers
who are not aware of the hazard likewise may store water-cored crops.

As water core predisposes apples to internal breakdown (fig. 11, B),
storing affected fruit for late marketing is always hazardous. Slight
water core in the long-season, hard-textured varieties, Winesap and
Yellow Newtown particularly, may disappear in storage without leaving
any trace; but in the short-season, softer varieties, even slight water
core is usually followed by internal breakdown, and this almost always
happens with more severe water core in even the harder varieties.

INTERNAL BREAKDOWN

Internal breakdown is a senility disorder that marks the end of the
storage life of apples. It is characterized by brownish discoloration of
the flesh, development of mealiness, and loss of flavor. In advanced
stages the skin of the apple cracks as though from internal pressure and
one can easily press the thumb deep into the flesh. In earlier stages,
however, there may be no outward symptoms except possibly a dull
color of the skin, often confined to the affected area. Cutting the apple,
however, reveals a brown discoloration in the flesh (fig. 11, B), some-
times only in the core region, sometimes throughout the whole interior,
and sometimes localized on only one side of the fruit. Occasionally,
the breakdown will be found at severe bruises. In such eases it doubtless
is due to the localized stimulation of respiration, which follows the in-
jury. This is another reason for careful handling to avoid bad bruises
and for sorting out badly bruised apples.

As internal breakdown is a senility disease, its presence in a storage
lot can ordinarily be taken as an indication that the apples either were
overmature when picked or have become overripe in storage. Further
holding of such lots is hazardous. The best way to prevent internal
breakdown is to harvest the fruit at the proper stage of maturity and to
retard its life processes as much as possible thereafter by holding it at a
temperature of 30° to 32° F.

SOFT SCALD AND SOGGY BREAKDOWN

Some varieties of apples are particularly subject to soft scald or soggy
breakdown in cold storage. These diseases are very much alike in nature
and cause, but they differ in their manifestation.

Apples affected by soft scald look as if they might have been rolled
on a hot stove (fig. 11, C). Strips or large spots of the outer tissues
are affected; the skin is dead and brown but tightly stretched with a very
definite demarcation of the margin. The underlying flesh is brown and
discolored. Only in late stages, however, is it more or less dried out;

HANDLING APPLES FROM TREE TO TABLE ae)

earlier, it is soft and juicy. Frequently, rot fungi invade the fruit
through the dead skin. They make black or brown spots of decay and
soon destroy what is left of the apple. Blue mold and Alternaria are
the most common invaders of soft-scald tissue. Jonathan, Rome
Beauty, and McIntosh are the varieties most often affected with soft
scald, but other varieties are sometimes affected also.

Much experimental work has been done on this disease, but very little
has been discovered to explain its nature and cause, except that it is a
low-temperature disorder. As a result, no categorical statements can
be made regarding its control. In general, its incidence appears to be
reduced or prevented by early harvest and prompt cold storage at 30°
to 32° F. Delay up to 10 days or 2 weeks in placing the fruit at 30° to
32° seems to increase the tendency to the disease, but after longer de-
- lays the susceptibility of the fruit decreases. Well-matured or over-
matured fruit is more susceptible to soft scald and should not be stored at
temperatures below 36°. The disease is erratic; it may be bad one year
and absent the next.

Soggy breakdown is most serious in Grimes Golden and Golden Deli-
cious and appears to be the manifestation in these varieties of the same
disorder exhibited by soft scald in others. Soggy breakdown differs
from soft scald chiefly in its location, being typically a disease of the
flesh, whereas soft scald is confined to the skin and adjacent flesh. Soft
scald has a sharply defined margin in the skin; in soggy breakdown there
is a more extensive invelvement of the flesh beneath, without the sharp
margin between the sound and the affected tissues (fig. 11, D). It seems
to be associated with the same storage conditions as soft scald.

SCALD

Seald occurs principally in storage; it is a rather generally diffused
browning of the apple skin. At first it is superficial, but eventually
the skin may become soft and it can be readily sloughed off. Then the
- flesh beneath either dries out or is opened to infection by rot fungi.
The green, or unblushed, parts of the fruit are most affected, and im-
mature apples are more susceptible than those picked later.

Scald can be understood best by thinking of it as a disease induced
by suffocation or auto-intoxication; that is, it appears to be caused by
products given off by the apple itself. The particular products involved
apparently are connected with the odorous constituents of the apples.

Scald itself affects the appearance and not the dessert or cooking
. quality of the fruit. However, the presence of scald means that the
further storage life of the fruit is limited because scalded skin is dead
and offers no further protection to the fruit. The disease is likely to
spread rapidly until almost all the surface, particularly the green-colored
areas, is involved. It does not ordinarily begin to appear until 60 days
or more after harvest and commonly is more serious on apples in cold
storage than on those in common storage. Sometimes it does not be-
come manifest until after the apples are removed to a warmer place.
Usually it becomes more serious after such transfer, but this is a result
of conditions that prevailed during cold storage.

In the prevention of scald, picking the fruit at proper maturity and

selecting only the best-colored fruit for long-time storage are important,
but in preventing loss from the disease further measures must be taken.

26 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

Since it is due to auto-intoxication effects in storage, storage practices
must be adapted to prevent its occurrence. If it were practical to pro-
vide continuous aeration of every apple, the injurious odorous emana-
tions could be removed in this way and scald control could be obtained,
but it is not possible to do this in commercial packages or under com-
mercial cold-storage practices. The only feasible method of scald con-
trol is the use of oiled paper (fig. 12) as developed by Brooks, Cooley,
and Fisher (2). The oiled paper can be used either in the form of fruit
wraps or shredded. It absorbs the odorous emanations from the fruit
and at the same time reduces moisture loss from the fruit. Its use is
recommended for all fall and winter varieties of apples. For best re-
sults the apples should be packed in the oiled paper as soon as possible
after harvest. Oiled paper for this purpose is now obtainable in all
apple-growing districts, but growers should make sure that it is properly
prepared and properly used. It should carry at least 15 percent of its
dry weight in an odorless and tasteless mineral oil. When shredded

Grimes Goiden

OneG | Wrapper

FiGureE 12.—Control of scald on Grimes Golden apples by use of wraps carrying odor-
less, colorless mineral oil to at least 15 percent of their dry weight.

oiled paper is used, at least 14 pound per bushel is required, and it should
be well distributed through the package so that every apple is in contact
with it. ; |

EFFECTS OF PACKAGING

Packaging practices have an important bearing on the subsequent
condition of apples, especially as to bruising, and particularly when
apples are displayed to the consumer. It is a strange commentary on
the apple industry that after taking great care to cull out all skin-punc-
tured and badly bruised fruit, many packers package their apples in such

HANDLING APPLES FROM TREE TO TABLE ae SPAT

a way as to bruise and puncture a large proportion of the good fruit re-
maining. Surveys in retail stores in various parts of the country reveal
that the outstanding defect in the apples offered for sale is bruising —
often very bad bruising. In self-service stores customers naturally do
not select badly bruised apples and in other stores such apples are
heavily discounted. Offering bruised fruit is contrary to the interests
of both seller and buyer, as well as of the producer. Often the industry
as a whole suffers in consequence, not only because of low profits but
also because consumers turn to more attractive competing fruits—
fresh, frozen, or canned—which may be available in the same store.

Examination of the apples before they are removed from the original
container shows that much of the bad bruising occurs after the fruit
is packed. The greatest single factor in producing this damage is the
trade’s insistence on a high bulge or heavy pack so that apples can be
‘bought by the package and sold by the pound. A high-bulge pack
usually brings the producer a few cents more than one that is merely
tight (as distinct from a slack pack); so many growers make it a rule
to put on the high bulge. Because such packs are favored in the whole-
sale trade but ultimately result in slowing down retail sales, their wide-
spread use points to a notable lack of coordination among the various
factors concerned in handling the commercial apple crop. However,
for the reasons indicated, it is not likely that this situation can be cor-
rected without an industry-wide effort. If the grower or packer could
reach the consumer directly, the practice would be abolished very
quickly, but when their contact is remote, and through intermediaries
whose interest in apples is only incidental, the problem becomes very
difficult.

Results of a survey conducted in the winter of 1940-41 by Crandall
in the retail stores of Columbus, Ohio, and reported by Nold (19),
show the extent to which bruising is found in apples offered for sale in
retail stores, as follows:

In determining the various types of damage, the following classification was used:
1. Slightly bruised—(Enough damage to affect the external appearance); 2. Severely
bruised—(Many small bruises or large bruises an inch or more in diameter); 3. Unde-

cayed skin breaks; 4. Decayed skin breaks.
... the average grocer’s display [of apples was found to contain the following:|

SOUMGBUBUGa = eter hme Ei oS Sa le in SS 57.9%
SligduelymlonwiseG arse sss ea ee 21.9
DENCH ly IRUISCG weet. Tua ee see ee Se 11-4
Skingonrealcsundecayed 42-2 ae ee Ey
Skangoredkcmolecavedasus ooh ee ee Si 3.6

... Since almost all of the fruit examined came either from the West Coast or from
‘Ohio, a check was made of the extent and type of damage prevalent on the fruit from
these two regions.
Ohio Western

Neu lyAWOEMISEG er Le ee ey 20.2 24.1
DEMME Wye WRUISCO Sor 5 i ONE On Sos Se 8.0 15.3
PEW, [OPRCSEH SSE 2 gg eg 6.6 3.5
Decayedeskin- Dreake. 1.2 ows Oi Be ee 4.4 2.7
SOU Glmeep eis sa Gea So a 60.9 54.3

... The Western fruit showed a large percentage of bruises caused by high pres-
sures ... Some boxes of fruit came through with very few if any pressure bruises while
others had as high as 50 percent severe bruising. Much of the damage is due to over-
packing the boxes in an effort to secure a heavy pack...

The Ohio-grown apples showed severe bruises that were evidently caused, for the
most part, by careless handling. Some of the severe bruising can be attributed to the
packing methods and containers...

28 CIRCULAR 659, U. 8. DEPARTMENT OF AGRICULTURE

The practice of overpacking alone accounts for many of the bruises present on the
apples in the grocers’ displays. For every apple added to form an extra large bulge,
there is at least one severely bruised apple and several slightly bruised ones. The extra
weight added in the form of a large bulge is more than offset by the waste and falling-
off in condition due to overpacking...

The type of package used has an important bearing on the prevalence
and severity of bruising that occurs during the handling of packed fruit.
The continuous-stave bushel basket is so generally recognized as unsuit-
able for fruit that it is not necessary to cite experimental results to prove
the point. Nevertheless, this package is still used to some extent for
apples. It is impossible to get and keep a firm, tight pack in this type of
basket. The nonrigidity of any side of the package makes it give under
pressure and permits the apples to be bruised or punctured in much the
same way that they are when a bag is used as a picking container (p. 18).
The nonrigidity of such baskets is especially objectionable when they
are stacked in storage or in transit.

The export tub is far superior to the continuous-stave bushel basket.
It has rigid sides and bottom, and the lid provides enough tension to
keep the pack tight. Overfilling this package is likely to result in rim
cuts as well as in bad bruising from pressure of the lid (fig. 13). Use of a
liner around the sides and a cushion or pad under the lid, although re-
tarding cooling as shown in table 1, is always desirable with bushel bas-
kets, in order to reduce the hazard of puncturing the apples by sharp
edges of the staves and the ends of the staples which sometimes project
on the inside.

F oo ee : - — = SEE

FicurE 13.—Bruised and cut Stayman Winesap apples fram the top ay er of a poe
type bushel basket that was packed too tightly. All the apples except one, which
are arranged to show injuries, were cut or badly bruised.

HANDLING APPLES FROM TREE TO TABLE 229

Bo Coe

Figure 14.—Bruised apples from overfilled standard box, like those in figure 15: A,
Severely bruised top layer, which could have been protected by a pad; B, second

_ layer showing outlines of bad bruises caused by pressure of first layer that was in-
creased by uneven sizing of the fruit; C, side layer showing bruises caused by stacking
boxes on bulged sides.

Close sizing of the fruit and place packing, or regular alinement, of
the fruit in the box are important in reducing the number of bruised
apples in a pack (fig. 14). Western packs, as a rule, are superior to
eastern packs, because the western packers use mechanical sizing ma-
chines, so that variations of more than one-fourth of an inch in the di-
ameter of apples in a package are rare. Fruit of each size is packed
according to a mathematical pattern. Also, each apple is wrapped
separately, a protection against bruising. Eastern packers, on the
other hand, often separate their apples into two sizes only—those larger
and those smaller than a certain minimum, usually 2%, 234, or 3 inches
in diameter. They may face their packages with apples of approxi-
mately the same size, but the jumble fill makes possible a good deal of
bruising, because the apples are not definitely placed and also because
of the uneven pressure of one apple against another that results when
apples of different sizes are packed together.

Studies by the United States Department of Agriculture show the
effect of packing on the bruising of the fruit (table 3). Apples from the

TABLE 3.—Comparison of bruising of Stayman Winesap apples packed in
standard apple box (northwestern box) and 114-bushel eastern crate

Apples badly bruised—

Package
Against each Against
other package
Percent Percent
tancdanceoxame stun alte ee ae ee 4 114
leyeabusmelacasberm. Crates >. 2. 2. 2 2 1, 229

_ 1} The distribution of this bruising was as follows: Top and bottom layers (against
padded lids), 1 percent; sides and ends (no pads but paper liners over sides), 13 percent.
2’The distribution of this bruising was as follows: Top layer (against pad), 1 per-

cent; bottom layer (no pad), 12 percent; sides and ends (cardboard liners but no pads),

16 percent.

30 CIRCULAR 659, U. 8. DEPARTMENT OF AGRICULTURE

same lot were packed at the same time in a Virginia orchard—part in a
11<-bushel apple crate and part in a standard apple box. Those in the
standard box were sized to pack 100 to the box; those in the crate were
sized 3 inches and larger, in accordance with commercial practice. Oiled
paper was used to wrap the apples in the standard box; shredded oiled
paper was used in the crate. Both packages had liners. Both also had
pads under the lids, but only the standard box had a pad in the bottom.
Both packs of apples were hauled by truck to Washington, D. C., where
they were held in cold storage for several months and then examined.
The results of the examination are given in table 3. The study revealed

SOR RRS SST Rt i

FicurE 15.—Bulging of top, bottom, and sides of standard boxes because of overfilling.
When such overfilled boxes are put under pressure in a stack serious bruising results
on apples in contact with the sides and the lids.

HANDLING APPLES FROM TREE TO TABLE eal

also that a pad on the bottom, as well as on the top, of the package helps
to prevent bruising of the fruit.

Figure 16.—Rome Beauty apples, showing typical flattened bruises produced by
jolting or vibration of the standard box against the car floor. Such injury can be
largely prevented by a cushion liner and careful handling of boxes.

947960—51—5

a2 CIRCULAR 659, U. 8S. DEPARTMENT OF AGRICULTURE

Bad bruising of western apples is usually the result of poor sizing,
poor alinement, overfilling (fig. 15) or rough handling of boxes, or of
jolting in the bottom layers of boxes in the car during shipment. - Apple
boxes are loaded on their sides, and it is not uncommon to find all
apples that are in contact with sides of boxes next to floor racks flat-
tened (fig. 16). This type of injury, sometimes mistaken for freezing
damage, can be lessened by use of a resilient cushion liner between the
apples and the sides of the box (27). Unpublished data of the United
States Department of Agriculture show that apples in boxes lined with —
4-way pads, which received regular commercial handling between a
northwestern cold storage and Texas retail stores, had 95.8 percent
more severe bruises than those in boxes protected from forceful impacts
during car loading and market distribution.

Sometimes apple boxes are overfilled to such an extent that they bulge
on the sides, which are supposed to be rigid, as well as on the top and
bottom (fig. 15). When a standard apple box rocks in a stack, the fruit
is sure to be badly bruised before it reaches the market (fig. 14, A and C).

Of increasing importance in commercial apple packaging is the use of
tray packs (fig. 17). The pressed-wood-pulp trays have cup-shaped de-
pressions to hold apples of a given size in perfect alinement and are
fitted in wood boxes or fiberboard cartons of slightly larger dimensions
than a standard apple box. Packing may be done by unskilled packers
if the apples are mechanically sized. These packages have proved very
effective in preventing the large bruises incident to box closure and

Eee ee i

Figure 17 nee carton re = a tray pack. The ee ee tray,
shown at the side of the carton, holds a layer of apples and protects the fruit from
excessive bruising against the sides and bottom of the container.

HANDLING APPLES FROM TREE TO TABLE _ 33

heavy impacts received during car loading, transit, and market distribu-
tion. The tray pack is growing in favor with buyers for self-service
markets where heavy bruising constitutes a difficult display and mer-
-chandising problem.

Fiberboard boxes, though not in common use for packing apples, are
being increasingly used for specialized packs. They may be used with
the tray-packs described above, as shipping containers for various types
of consumer packages, or with egg-crate-type cells for individual apples
(fig. 18). The latter afford maximum protection against bruising.
Because of the diversity of sizes of the egg-cell inserts required for dif-
ferent sizes of apples, boxes of various shapes and dimensions are re-
quired. This makes it difficult to stack them in cars, trucks, or storages
economically. Corrugated fiberboard is a good insulating material: con-
sequently allowance for ventilation should be made in their design.
They hold the fruit less rigidly in place than wooden containers, and
if they are not moistureproofed they tend to soften at the high humidi-
ties desirable for apple storage. However, shipments of apples in fiber-
board boxes have been made from the Northwest to eastern markets
in which the fruit arrived in as good condition as that in the standard
boxes.

Ficure 18.—Egg-crate type of fiberboard containers, which afford maximum protec-
tion against bruising. A disadvantage of this type is the diversity of shapes required
for apples of different sizes.

PREPACKAGING FOR THE CONSUMER

A wide variety of packages, varying in size from 14 bushel down to
a 2-pound carton, have been used in an effort to find a container that

34 CIRCULAR 659, U. 8S. DEPARTMENT OF AGRICULTURE

the retailer could offer for sale as a consumer unit. In addition to
those mentioned, various paper boxes, overwrapped trays or boats,
mesh bags, and bags made of transparent films have been used (figs.
19 and 20). As the smaller 2- to 5-pound units are usually shipped
in master containers without excessive closure pressure, the apples so
packed reach the retail store with fewer bruises than those packed and
shipped in ordinary containers.

Apples to be prepackaged must be sound when packed and not sub-
ject to such disorders as rots, soft scald, bitter pit, breakdown, or scald
during transit and market distribution. This is very demanding. Scald,
for instance, may make it impossible to pack certain varieties within 2
months after harvest or necessitate packing them in oiled paper at the
time of harvest. Apples become increasingly susceptible to rot invasions
as the storage season progresses. Hence safeguards against decay in-
vasions must continuously be intensified when prepackaging during
the winter.

Figure 19.—A 5-pound carton of York Imperial apples packed for the consumer in a
Virginia packing house.

The package must adequately display the apples or the consumer will
select fruits from bulk displays. Net mesh bags may make an imprint
on soft varieties. Film packages should be perforated, or at least not
completely sealed, so that apples will not develop undesirable flavors
because of lack of oxygen. Each package must contain more than the
stated net weight when packed to allow for shrinkage during distribu-

HANDLING APPLES FROM TREE TO TABLE 35

FiguRE 20.—Apples packed for the consumer in bags made of transparent film.

tion. Otherwise, the retailer may become liable for violation of local
weight and measure laws or ordinances. A closure that prevents re-
moval of apples from one package to replace those in another is desir-
able for the package. Also, the consumer packages should be strong
enough to resist breaking during delivery to the retail store and while
being handled during display and sale by the retailer.

THE SHIPPER’S RESPONSIBILITY

Many apples are shipped to markets far from producing areas and
frequently are in transit from 1 week to 2 or 3 weeks before being un-
loaded. Most of the shipments are made in refrigerator cars. The
protective service they receive in transit depends on what is ordered by
the shipper. It may be ventilation, refrigeration, or heater service for
protection against freezing.

36 CIRCULAR 659, U. 8. DEPARTMENT OF AGRICULTURE

Because apples are not highly perishable, like peaches or strawberries
for example, and move during the cool seasons, many shippers order
their cars shipped under ventilation. Under this service no particular
control of the temperature of the load is possible; the vents are kept
open at all times when the outside temperature is above a stated mini-
mum, usually 32° F., and are closed when the outside temperature drops
to this minimum. If the fruit is warm when it is loaded, cooling in
transit depends entirely on lower outside temperatures. If the fruit is
colder than the outside air, the load will warm up. This is particularly
likely with shipments from cold storage. Such shipments should never
be forwarded under ventilation service. If transit refrigeration is not
desired, they should be billed “Plugs in. Vents closed to destination.”’
Thus the refrigeration stored up in the cold load can be utilized through-
out the trip.

Movement under this service or under ventilation provides the
cheapest services available to the shipper. From the standpoint of the
condition of the fruit, the use of ventilation is justified only with apples
that are intended for immediate use. With apples intended for storage
at destination, ventilation service jeopardizes the potential storage life
of the fruit because of the rapidity with which the ripening process pro-
ceeds at higher temperatures (p. 9). Consequently, as a rule, apples
that move under ventilation are not worth as much as those that are
refrigerated in transit. This does not mean that ventilated shipments
necessarily sell for less than refrigerated consignments, but it does mean
that they are likely to give less satisfaction to the consumer, thereby
doubtless indirectly affecting the market for apples in general. Shippers
who use ventilation service indiscriminately are to that extent increas-
ing the hazards of the industry and inviting dissatisfaction among con-
sumers, which must affect the demand for apples.

Shipments can be billed to move under standard refrigeration or
various modifications of it. Under standard refrigeration the bunkers
of the car are initially iced to capacity and are refilled at all regular icing
stations en route (usually at least once every 24 hours), and the car is
delivered with bunkers at least three-fourths full. When shipments are
precooled or are loaded out of cold storage and move under standard
refrigeration, maximum protection is obtained.

Sometimes modified refrigeration services can be utilized to effect
savings in cost without sacrificing efficiency of refrigeration, and shippers
are utilizing such services to an increasing extent. It is possible, how-
ever, that some apple shippers are going too far in this direction. The
apple does not ripen as rapidly as some other fruits, but every day that
it is kept above the optimum storage temperature means a progressive
shortening of the time before it will become fully ripe and presently over-
ripe and undesirable or unsalable. Consequently, protective services,
providing relatively high temperatures during the transit period, inter-
ject an element of hidden damage to the potential storage quality of
the fruit. The degree to which this damage may be hidden, or the time
at which it will become apparent in the ripening of the fruit, depends on
the condition of the apples at time of shipment and their temperature
while in transit. It is more likely to be serious with varieties like Jona-
than, Rome Beauty, and Delicious, which are often left on the trees
until past proper picking stage in order to get more red color, than with
later keeping varieties, such as Winesap and Yellow Newtown.

HANDLING APPLES FROM TREE TO TABLE == By

The effects of hidden damage are probably greatest in shipments that
move under heater service. Mallison, Gorman, and Hukill (78) found
that heater service often warms the fruit in the car to temperatures
- that would call for the use of refrigeration in summer shipments. Such
inconsistency is due to the impossibility of closely regulating the heat
supplied and its distribution in the car with ordinary heating devices.
The temperature in the bottom of the load is sometimes down to freez-
ing when that in the upper layers is up to 60° F. or higher. Unquestion-
ably a great deal of damage has been done to winter shipments of Deli-
cious and other varieties, which are especially prone to become mealy,
by the heater service used to protect the fruit against freezing while in
transit.

Recent investigations by the United States Department of Agricul-
ture and the Association of American Railroads have shown that these
conditions can be largely corrected by using heaters having thermostati-
cally controlled burners in cars with air-circulating fans. The mechanical
circulation of the air within the car was shown to be very important.
It provided a means of protecting apples against freezing during short
periods of cold weather without supplementary heat; when heat was
supplied less heat was required and it gave protection against freezing
without excessively high temperatures at the top of the load. With
greater numbers of cars equipped with fans now available, apple shippers
would.do well to use them at every opportunity, especially when low
temperatures are likely during shipment. When sustained low tempera-
tures are probable, as after the middle of November with shipments
across the northern part of the continent, the mechanical circulation
of air should be supplemented with heater service. Otherwise, freezing
throughout the load may result if the shipment should encounter several
days of near-zero weather.

THE DEALER’S RESPONSIBILITY

From what has been said so far, it might appear that the condition and
quality of apples are predetermined by what happens to the fruit before
it reaches the dealer. This is true in large measure, but there are a num-
ber of things that the dealer can do to reduce deterioration of the apples
he buys for resale. To list them would be for the most part to repeat
the factors already enumerated, but with special application to condi-
tions under the dealer’s control.

Apples at proper harvest maturity usually have not reached their

highest eating quality. The maximum dessert quality appears after a
storage period, the length of which varies with different varieties, stage
of maturity at time of harvest, and the storage temperature. After
they have reached maximum dessert quality they begin to deteriorate.
The longer they are held in storage the shorter will be the marketable
life when removed for sale.

The first responsibility of the dealer is to buy good fruit, but this does
not necessarily mean buying fruit marked “Extra Fancy” or “U.S. No.
1.” These grade designations, even though they may have honestly
described the quality of the fruit at the time of packing, do not reflect
changes in condition, such as ripeness, decay, and seald, that have taken
place during storage. The buyer should have the apples inspected at

the time he intends to purchase them in order to determine the extent

38 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

to which deterioration has progressed since the apples were graded and
packed. Most dealers make such inspections themselves or have the
opportunity to do so. Hence, if they buy fruit that is badly bruised,
overripe, more or less decayed, misshapen, wormy or scale infested, or
cull, presumably they do it with the intent to offer that class of fruit
to customers.

The wholesale dealer, in making purchases at shipping point, has the
responsibility of ordering the transit protective service. Through either
experience or consultation with experienced shippers he should make
certain that the protection is adequate for the particular fruit being
shipped under the weather conditions that are likely to prevail. Whole-
sale and retail dealers have a joint responsibility in handling fruit after
transit. Serious bruising results every time a box or basket of apples is
slapped down on floors, on truck beds, or on other packages. These
heavy impacts, which may occur several times after a package has been
received at a terminal market, contribute heavily to the number of
badly bruised apples reaching the retail bin.

Next to bad bruising, overripeness is the greatest cause of complaint
among retail purchasers. A criticism often heard is, ‘“‘Nice-looking large
red apples, but mealy and tasteless.” That always means overripe
apples. How fast do apples get overripe? The answer depends on the
temperature—in the retailer’s store as well as in commercial storage or
in the hands of the grewer after harvest. Apples ripen about twice as
fast at 70° as at 50° F., twice as fast at 50° as at 40°, and twice as fast
at 40° as at 32° (p. 9). If they are ripe when bought for sale, some kinds
(Delicious in particular) can become overripe and mealy in 2 or 3 days
at ordinary store temperatures and in even less time if they are piled
behind windows for display and are not protected against hot sunshine.
The safest procedure for a retail merchant is to regard apples from cold
storage late in the season as being as perishable as peaches at the height
of their season and to move the apples into consumers’ hands before
they have a chance to get overripe and out of condition..

Apples purchased in small lots usually cost more than those obtained
in large quantity; hence, retailers may buy more than they can dispose
of before the fruit gets overripe. Unless refrigeration facilities can be
utilized, the merchant who woula sell only apples not beyond their
prime should obtain fresh stock from cold storage at intervals of not
over 2 or 3 days rather than hold a surplus in a warm place. If some of
the fruit must be held over, especially during warm weather, the best
place to keep the apples is in a refrigerator. Some stores have a special
walk-in refrigerator for fruits and vegetables; others utilize space in the
meat cooler; and an increasing number of stores are now installing
open refrigerated cases with storage compartments below the retail
display shelves. If refrigeration is not available, the apples will benefit
by being held in a cool, well-ventilated place, perhaps in the stockroom,
where screened or barred windows can be left open, or in a cool base-
ment room.

Packed boxes should always be stacked on the side (fig. 15), and never
on the top, which is bulged to hold the fruit in place, or on the end,
which will concentrate the weight on a smaller area and increase
chances of bruising. Only when the top is removed and pressure is
released, is it safe to let the boxes rest on the bottom lid. Bushel baskets
should be staggered by placing one basket on the edges of two others,

HANDLING APPLES FROM TREE TO TABLE . 09

keeping all pressure away from the center of the lids (fig. 5). To provide
good air circulation, which is needed to keep the fruit cool in warm
weather, containers of apples should be kept away from outside walls
and should be placed on a false floor or slatted platform with 3 or 4
‘inches of air space beneath. These measures will also reduce danger of
freezing damage in cold weather.

In displaying apples the fruit should be kept away from potatoes,
onions, and other root crops from which they may absorb odors. Apples
should also be kept away from wet, green, leafy vegetables that are
sprinkled to keep them fresh. The apples themselves should never be
sprinkled, as this may stimulate decay. However, apples deteriorate
rapidly when exposed in warm, dry air; hence, most of the stock should
be kept in the original containers (fig. 21). Displays should not be made
near radiators, stoves, or sunny windows, and they should be of such
size that they will have to be renewed frequently with fresh stock.

Figure 21.—Retail display of apples mostly in their original containers, in which they
keep best, and away from potatoes and root crops, from which they may absorb
odors, and from leafy vegetables, which are sprinkled to keep them fresh.

Frequently. dealers make mass displays of apples, removing them
from the containers and piling the fruit in pyramids or otherwise in large
lots. This contributes to bruising damage unless very carefully done.
In self-service stores, where customers are free to select the fruit that
they purchase and where in consequence it may be handled a good
deal, the bruising is increased considerably after the apples are put on
display. The extent of this damage, of course, varies, but that it may
be serious is shown by the conditions observed in one of the stores
covered by Crandall in the survey reported by Nold (19). Crandall ex-

947960—51—6

40 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE

amined the fruit in original containers just as it was delivered to the
store and also some of the same lots as they were displayed for sale.
His findings (table 4) show that, although handling in the store increased
the damage considerably, most of the bruising was present when the
apples were unpacked.

TABLE 4.—Condition of apples before they were unpacked and after display

for sale
| Sound in |
Variety original | Sound nen
| RACARe on display
Percent — Percent

omar Ghia ace pes oa ee ee lee ee eee 64 54
Golden Delicioust=se 2) 540-52 #2 etc tee eee LD 48
Be law ace 2 cee pee os nae Se ae gig fo ae 93 43
Greening. 2 ees e Set Nee oe eS SA Seo ye eae (fl 56

Crandall’s results are in general agreement with those reported by
Kross and Slamp (14), who made a somewhat similar study in New
Jersey. They found that 42 percent of the apples on display in the retail
stores they surveyed showed old bruises and only 8 percent had fresh
bruises as the result, apparently, of handling in the stores.

If the retailer would give his trade the kind of apples that will stimu-
late demand, he must consider the variety as well as grade and condi-
tion. In order to make even such a rough classification as eating apples
and cooking apples, as is frequently done in grocery stores, the dealer
needs to know something about the principal commercial varieties so
that, for example, Rome Beauty, York Imperial, or even Ben Davis
will not be offered as eating apples or Delicious as a good baking apple
because it has good size. He also needs to know when each is in season.
It is not uncommon to find Jonathans and Winesaps offered together.
In the fall only the former could give satisfaction, but in late spring the
Winesap would be preferred.

While upward of 200 varieties of apples are grown in the United
States, only 15 are commercially important (table 5). Farmers’ Bulle-
tin 1883 (15) gives more information on apple varieties.

Some of the varieties listed in table 5 are good both for eating out of |
hand and for making sauce, pie, and other dishes; others are best adapted
to one or the other of these uses. Yellow Transparent, for example, is: too
acid to please most people for eating out of hand, but it is one of the
best for making sauce and pie. Delicious, on the other hand, is too lack-
ing in acidity for cooking, but is the leader for the fruit-stand trade.

The character of the flesh of a variety when ripe is an important con-
sideration for all handlers of apples, for, in general, it indicates the sus-
ceptibility of the fruit to bruising and how it will withstand handling,
especially 1 in bulk or in the retailer’s bins. Important in this connection
also is the color of the fruit. Apples listed as soft in table 5 are most
likely to become badly bruised, while those listed as hard are less likely
to be damaged by ordinary handling. Those marked firm are inter-
mediate in this respect. Asa rule, varieties that are solid yellow or green

HANDLING APPLES FROM TREE TO TABLE - 4]

show bruising much more readily than red or striped varieties although
actually they may not be bruised to any greater extent. Consequently,
they have to be handled much more carefully if the appearance of the
apples is not to be affected.

TaBLE 5.—Characteristics of principal commercial varieties of apples

Flesh
Variety Color Principal use when Marketing season
ripe
Yellow Transpar- | Yellow__| Cooking-____------ Soft. 35-2 July to August.
ent.
Gravenstein____ _- Striped__| Eating and cooking_|__-_do_-__- July to September.
Wealthy. 257%: 13.412) [eer ae Omir Sole he be doe S=: September to De-
cember.
Meintoshe 22622 |e don ee doses On Le ee dove): September to Jan-
uary.
Grimes Golden___| Yellow__|---- (6 oi Se as pe Peres Do.
Jonathan’ 22-622 edi tue |e ae Coes ey ee dos September to Feb-
ruary
Deliciouse 2 54522 |22 dows. Hasta Gee oe ee | es doze see Se nteaher to April.
Rhode Island Greeni_:| Cooking 2 2032-1 la). doses October to March.
Greening.
Golden Delicious_| Yellow__| Eating and cooking_|___do____- October to April.
Work lanperialse |) Red 2) Cooking: 2. 9200.7 Hard____| October to March.
Stayman Winesap|---do___-| Eating and cooking-| Firm____- November to April.
Ballciwais 3-505 S| do 22 sa|_ 35 (6 CO ke AS a a dos ate Do.
Rome Beauty - ---|--- dos» 2) (Cookinpic 0 oto 60) alana November to May.
Yellow Newtown- Green or Eating and cooking_| Hard__-__| January to June.
yellow.
WWimesap= 22 2s. Red say alcces doe epee Seen do seins Do.

The marketing season indicated for the varieties in table 5 is the.
period during which commercial supplies should be at their best. If put
on the market earlier the apples are likely to be unsatisfactory either
because of immaturity (being picked too soon) or because they have.
not had a chance to ripen sufficiently. If they are offered later than
their normal marketing season they may still be in good condition and
may still give consumer satisfaction if they have received exceptional
care in handling and storage, but the hazards of their soon becoming:
overripe or of quick breakdown are greatly increased. Much of the
complaint about overripeness in apples is due to their being stored be-.
yond their normal marketing season.

THE INDUSTRY’S RESPONSIBILITY

The most practical approach to the problem of getting good apples:
to the consumer seems to lie in a close coordination of all elements
in the industry to apply good handling methods at all times during
the marketing process. Success of any such effort will doubtless require.
the initiative to be taken by apple producers and shippers. They are.
not only the most immediately concerned but also have the requisite.
knowledge and appreciation of the technical requirements for handling
the apple. Their business is often tied up closely with apples alone,
whereas to others in the trade apples are only one item of merchandise.
Success of such an undertaking depends also on sustained industry-wide.

42 CIRCULAR 659, U. 8. DEPARTMENT OF AGRICULTURE

cooperation rather than on the sporadic initiative of individuals. It
can perhaps best be attained through the specialized organizations
that have been set up for the purpose of promoting the sale of apples
generally. With adequate support of these organizations by growers
and shippers, and close-knit cooperation between such organizations in
different parts of the country particularly, much could be done. Suc-
cess would require an educational or demonstration program based on
two fundamentals that apply to all in the industry: (1) The intrinsic
worth of the apple as an article of diet and (2) the necessity of keeping
apples in good condition to maintain their intrinsic worth as food.

LITERATURE CITED

(1) Bavjnr, &: P.
1943. HARVEST SPRAYS FOR THE CONTROL OF FRUIT Drop. U.S. Dept. Agr.
Cir. 685, 16 pp., illus. .
(2) Brooks, C., Coo.ey, J. S8., and FisHzr, D. F.
1919. NevOEE AND CONTROL OF APPLE-SCALD. Jour. Agr. Res. 18: 211-240,
illus.

(8) Cootey, J. S., and Fisumr, D. F.
1936. DISEASES OF APPLES IN STORAGE. U.S. Dept. Agr. Farmers’ Bul. 1160,
20 pp., illus. (Revised.)
(4) and FisHer, D. F.

1926. WATER-CORE OF APPLES. Jour. Agr. Res. 32: 223-260, illus.
(5) Eneuisu, H.
1948. DISINFECFANT WASHES FOR THE CONTROL OF DECAY IN APPLES AND
PEARS. (Abstract) Phytopathology 38: 914.
(6) GERHARDT, F.
1950. AIR PURIFICATION IN APPLE AND PEAR STORAGES. Refrig. Engin. 58:
145-148, 192-194, illus.
(7) Hauer, M. H.
1941. FRUIT PRESSURE TESTERS AND THEIR PRACTICAL APPLICATION. U. S.
Dept. Agr. Cir. 627, 21 pp., illus.

(8) Lutz, J. M., and Mattison, E. D.
1941. THE RELATION OF FIRMNESS TO RIPENESS OF EASTERN-GROWN APPLES.
U.S. Dept. Agr. Cir. 579, 22 pp., illus.
(9) and Maengss, J. R. ;
1944. PICKING MATURITY OF APPLES. U.S. Dept. Agr. Cir 711, 23 pp., illus.
(10) and Situ, E.

1950. EVALUATION OF INDEXES OF MATURITY FOR APPLES. -U. 8. Dept. Agr.
Tech. Bul. 1003, 53 pp., illus.
(11) Huxi1, W. V., and Smiru, E.
1946. COLD STORAGE FOR APPLES AND PEARS. U.S. Dept. Agr. Cir. 740, 61
pp., illus.
(12) Kipp, F., and Wsst, C. .
1950. THE REFRIGERATED GAS STORAGE OF APPLES. [Gt. Brit.] Food Invest.
Bd. Leaflet 6, 13 pp., illus. (Revised.)
(13) Krenuo1z, J. R., Ropinson, R. H., and DEeman, E. 8S. :
1949. REDUCTION OF PEAR ROTS IN OREGON BY THE USE OF A CHEMICAL WASH.
Oreg. Agr. Expt. Sta. Cir. Inf. 460, 7 pp. [Processed.]
(14) Kross, J. I., and Suamp, K. R.
1941. SELLING APPLES DIRECTLY TO RETAIL STORES. N.J. Agr. Col. Ext. [Un-
numbered. Pub.], 9 pp. [Processed.] ;
(15) Maensss, J. R.
1941. APPLE VARIETIES AND IMPORTANT PRODUCING SECTIONS OF THE UNITED
states. U.S. Dept. Agr. Farmers’ Bul. 1883, 32 pp., illus.

(16) Dien, H. C., Hatter, M. H., and others.
1926. THE RIPENING, STORAGE, AND HANDLING OF APPLES. U.S. Dept. Agr.
Dept. Bul. 1406, 64 pp., illus.
(17) and Taytor, G. F.

1925. AN IMPROVED TYPE OF PRESSURE TESTER FOR THE DETERMINATION OF
FRUIT MATURITY. U.S. Dept. Agr. Dept. Cir. 350, 8 pp., illus.

HANDLING APPLES FROM TREE TO TABLE . 43

(18) Mautison, E. D., Gorman, E. H., Jr., and Huxi11, W. V.
1937. PROTECTION OF APPLES AND PEARS IN TRANSIT FROM THE PACIFIC NORTH-
WEST DURING WINTER MONTHS. U.S. Dept. Agr. Tech. Bul. 550, 55

pp., illus.
(19) Nop, T.
1941. HOW APPLES DECLINE IN VALUE. Natl. Apple Inst. Bul. 35, [3] pp. [Proc-
essed.

(20) Rosn, D. H., Brooks, Gy FisHer, D. F., and Brat LEY, C. O.
1933. MARKET DISEASES OF FRUITS AND VEGETABLES: APPLES, PEARS, QUINCES.
U.S. Dept. Agr. Misc. Pub. 168, 71 pp., illus.

(21) and Lutz, J. M.
1933. BRUISING AND FREEZING OF APPLES IN STORAGE AND TRANSIT. U. S.
Dept. Agr. Tech. Bul. 370, 15 pp., illus.
(22) Wriaut, R. C., and WHITEMAN, T. M.

1949. THE COMMERCIAL STORAGE OF FRUITS, VEGETABLES, AND FLORISTS
stocks. U.S. Dept. Agr. Cir. 278, 60 pp. (Revised.)
(22a) Scuomer, H. A., and McCottocu, L. P.
1948. OZONE IN RELATION TO STORAGE OF APPLES. U.S. Dept. Agr. Cir. 765,
24 pp., illus.
(23) Smiru, E., ApaMs, D., and Wricut, T. R.?
1949. INVESTIGATION OF APPLE BRUISING: WENATCHEE, WASH. 1948-1949.
U.S. Bur. Plant. Indus., Soils, and Agr. Engin., H. T. & S. Off. Rpt.
211, [16] pp., illus. [Processed.]
and Wriaut, T. R.4
1948. SOURCE OF APPLE BRUISES: WENATCHEE, WASHINGTON 1947. U.S. Bur.
Plant Indus., Soils, and Agr. Engin., H. T.é & Off. Rpt. 190, 10 pp.
[Processed. ]
(25) Smock, R. M., and Soutuwick, F. W.
1948. AIR PURIFICATION IN THE APPLE sToracE. N. Y. (Cornell) Agr. Expt.
Sta. Bul. 843, 52 pp., illus.
and VAN Dorgn, A.
1941. CONTROLLED-ATMOSPHERE STORAGE OF APPLES. N. Y. (Cornell) Agr.
Expt. Sta. Bul. 762, 45 pp., illus.
(27) Wricut,.R. C.
1942. THE FREEZING TEMPERATURES OF SOME FRUITS, VEGETABLES, AND
FLORISTS’ stocks. U.S. Dept. Agr. Cir. 447, 12 pp. (Revised.)
LumspEn, D. V., WuiTeMan, T. M., and Byrnss, J. W.
1941. SOME EFFECTS OF APPLES AND OTHER FRUITS ON THE STORAGE LIFE OF
CUT FLOWERS. Ice and Refrig. 100: 149-150, illus.

(24)

(26)

(28)

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