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Circular No. 278
The Commercial Storage of
Fruits, Vegetables, and
Florists’ Stocks
DEAN H. ROSE, Senior Physiologist e R. C. WRIGHT, Physiologist
T. M. WHITEMAN, Associate Horticulturist
Division of Fruit and Vegétable Crops and Diseases
Bureau of Plant Industry, Soils, and Agricultural Engineering
Agricultural Research Administration
For sale by the Superintendent of Documents, Washington 25,D.C.- - - = 2+ = = = Price 20 cents
UNITED STATES DEPARTMENT OF AGRICULTURE
WASHINGTON, D. C., JULY 1949
goers ATA
: OTL ER ARTI
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t
Circular No. 278
September 1933 * Washington, D.C.
Revised November 1941 ° Slightly revised July 1949
UNITED STATES DEPARTMENT OF AGRICULTURE
The Commercial Storage of Fruits,
Vegetables, and Florists’ Stocks
By Dean H. Ross, senior physiologist, R. C. WRIGHT, physiologist, and T. M.
WHITEMAN, associate horticulturist, Division of Fruit and Vegetable Crops and
Diseases, Bureau of Plant Industry, Soils, and Agricultural Engineering,
Agricultural Research Administration *
CONTENTS
Page | Fruits and nuts—Continued Page
lnttroductiomee 2 8 eee 2 igs s(inesin) see So 2 ele. 21
Factors involved in cold storage_ 3 Grapeiritit oe ee es 21
Temperature of storage rooms 3 Grapesed tev ila eae Feeds fal is 22
Humidity of storage rooms _ _- 5 JESINcK) OVS) Ym Le PRE Wie NRSC OR eer 23
Evolution of heat by com- TSWNE Sime ioe tee ae oy es Oe 24
MOOG Vee Meee soe ees. Y 6 Logan blackberries ____------ 24
Effect of cold storage on subse- Olives. @iresh) 2VeRI es Horas ts 24
quent behavior of fruits and Orangesse cts Wee Tes 24
vegetablesaei eo ne ae se 12 JERSPY Gl aVeSpsMeel ay Ss 2 Dy ips Sn ona tl es 25
Sea Glin Geers Me renee hee 13 REARS RSE Saks als ea i kein ea ey 25
Wading Merais “CULE is Ti Pas 13 Pineapplese: 24's Ul tare Gal
Choice of storage conditions__-__ 13| Plums (including prunes) _-__-- 27
Bnuicseancenitsyye Stel. 2 ek Eee 14 Quince says See eee ee ee Te 28
PATO DLE Si ae ets care ih le Ss a ee 14 VASP Derries : 420 ess Cais sete 28
TeV OVS(COUS es Se cl eeeaes IVA Strawberries ce eee o Leeman 28
Wvocados:!£ Libis, Cult it 17 Dried irultses. 22 se eae om 28
Bananas _____-------------- 18| Frozen fruits and vegetables_- 29
Bldiekberriés fat. s.r v8). 19 Nut 29
Cleric sits he spar Giese oe a 1 ee a Le ee
Care ete ea Ton ceetablester ses) 2 === 22-2. 30
Cranberricsue i. Ss rie 19 AS WATAg USS. jee” 22 Sanaa 31
Date sw nts bee Ee eS DO Beans: Pls sae eet Si ee es 32
Dewhermiegi 2 te) oe tee 2 ee 21 BOGGS eee ere ie Sir) ate 682 1 32
*The writers not only have included results of their own investigations but
also have drawn freely on published and unpublished results of other staff
members, whose assistance and cooperation have done much to make possible this
publication in its present form. Acknowledgment for unpublished information
furnished on refrigeration or commodities indicated is due the following present
or former members of this Division: W. R. Barger, dates and dried fruits; C. O.
Bratley, limes and pineapples; Fisk Gerhardt, A. L. Ryall, and W. H. English,
pears; C. W. Mann, lemons; W. T. Pentzer, refrigeration, garlic, olives, pears,
and peppers ; Edwin Smith, refrigeration, apricots, and pears; Morris Lieberman,
lima beans, cabbage, celery, and cucumbers; M. H. Haller, spinach; E. B. Lambert,
mushrooms. Acknowledgment is aiso due J. N. Kelley, Fruit Dispatch Co., for
information on bananas. Special acknowledgment is made to D. F. Fisher, of
this Division, for valuable suggestions and criticisms throughout the preparation
of this and earlier editions of the circular.
829965—49——1 1
2 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
Page Page
Vegetables—Continued Vegetables—Continued
Broccoli (Italian, or sprout- Pease (Green) S22 ee ee ener 41
ING) = eee he eee 33 Peppers =: >a See 41
Brusselsssprouts_- = 2s sees 33 Potatoes: 2. 2s 2 eat SF 41
Galbuges ts0220 425.2" 4 See 33 Pumpkins and squashes-__---- 43
Carrotseyye (er 22 Jos ee 34 Radishes (winter) _..._.------ 44
Camlilgwerss 222 Ss =e errs 34 Rhubarbsss = 2 ees 44
Celermac: 2458 2s eee 35 Rutabagas st... 2s See 5 44
Gelerysc 25-3 Si eee ees 35'|: **Salsifiye se 5 ee fa eee eS 44
Corn (eneem) hes ceases 36 Spinach: Ss aee ae. eee a4
Cucumbers ent oe eer 36 Squashes acess ewe eee 44
Hooplants es eee 37 Sweetpotatoes= == se 44
Endive, or escarole_____-____- 37 Pomatoes ss. Se See ae 45
Garlies(dry ia See 37 (PUTRI S ey a ye ee 45
Horseradish #2 2 a By Frozen vegetables______.---- 46
Jerusalem-artichokes.._ - -__-- 37 | Cut flowers, florists’ greens, rhi-
Kohitahi == 38 zomes, tubers, corms, and
Leeks (green) <2 2 = eee 38 bulbs 46
Hhettuce= 2s Ge Se a ee 38 Cut fi Setgoeiesse
MicloTish 352 ree ss eee ee 38 aes owers eR eed er 48
Mushrooms (cultivated) wee 39| Florists’ greens______-------- 92
Owes Si Sia ae 29 Rhizomes, tubers, and corms _ 53
Onions and onion sets____-__- 391) Bulbssse SA eo ees 54
Parsnips= sau eee eee se en 40; Literature cited === 222 —="* eae 54
aR RS ARR
INTRODUCTION
The purpose of this circular is to present a series of brief sum-
maries of the essential average storage requirements of most of the
more important varieties of fresh fruits, vegetables, cut flowers, and
certain other perishable commodities that enter the market on a
commercial scale. Many details are of necessity omitted, as the work
is intended primarily for general practical reference. The conditions
given should not be considered as absolute or final, but rather as the
safe limitations under which the various products can ordinarily be
stored. Detailed information on the handling and storage of some
of the commodities discussed is available elsewhere in the form of
bulletins or textbooks; for many of them only general information
exists.
Fresh fruits, vegetables, cut flowers, etc., intended for storage
should be as free as possible from skin breaks, bruises, and decay.
They should be neither immature nor overmature, because in either
case it may be difficult to keep them from too rapid deterioration,
and even if they do not change appreciably in storage, they will not
be commercially desirable when removed. The proper degree of
maturity in each case can usually be determined by consulting the
various sections of this circular, or the publications listed in Liter-
ature Cited (p. 54), or on the basis of previous experience. There is
a seasonal variation, however, in the storage quality of certain prod-
ucts, particularly fruits; hence care must be taken not to assume too
much from one year’s experience concerning the probable behavior of
a given commodity grown the next year.
Decay and other deterioration in storage is too broad a subject to
be discussed in detail in this publication. It is discussed very gener-
ally in connection with various fruits and vegetables covered by this
.
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 3
circular and in greater detail in other publications (8, 14, 22, 38, 44,
58, 72, 77, 78, 79, 80, 82, 83, 84, 85, 86, 88, 95, 98, 109, 110, 112) ?
FACTORS INVOLVED IN COLD STORAGE
Recommendations for the best conditions for the storage of fresh
fruits, vegetables, and cut flowers are subject to change from time to
time as more definite information is gained in the handling of these
commodities. The conditions and requirements given in this circular
are derived from the best commercial practice at the present time
and from scientific experimentation. The term “cold storage” as
used in this circular refers to storage where temperatures in the ap-
proximate range of 25° to 45° F. are maintained by mechanical means
or by the use of ice and salt; “freezer storage” to temperatures rang-
ing from about 15° to —20°, usually close to zero; “cool storage” to
temperatures ranging from about 50° to 65°, or possibly 70°; “un-
refrigerated storage” to temperatures that are allowed to fluctuate with
outside temperature; and “common storage” to storage in which the
temperature best suited to the commodity is obtained as nearly as
possible by insulation and ventilation only.
All of the temperature requirements are given in degrees Fahrenheit
and represent the average air temperatures that should be maintained.
The humidities are relative and are expressed in percentage of satura-
tion; for example, when it is stated that a certain humidity should be
85 percent, this means that the air should be at approximately 85 per-
cent of complete saturation with water vapor at the recommended
temperature. Allowance has been made for the facts (1) that the
temperature of fruits and vegetables in transit is usually higher than
the recommended storage temperature, (2) that, except during winter
weather, ripening or other changes are likely to go on more rapidly
during a given transit. period than during the same length of time
in cold storage, and (3) that when the commodities arrive at destina-
tion, even if they had been in storage at shipping point, they are likely
to be somewhat more mature than if they had remained in storage the
whole time.
‘TEMPERATURE OF STORAGE RooMs
If the best results are to be obtained in the cold storage of the prod-
ucts discussed herein, it is highly important that the temperature in
storage rooms be held fairly constant. Variations of 2° or 8° F.
above or below the desired temperature are in most cases too large.
They can usually be avoided if the storage rooms are well insulated
throughout and have adequate coil surface and if the spread be-
tween the temperature of the refrigerant and that of the room to be
refrigerated is kept small. For example, in a room where 45° is
the desired temperature, using ammonia evaporating at about 26°
in the coils, fluctuations of =114° may occur in the air temperature
in the room; whereas at 32°, with ammonia also at 26°, fluctuations
in the room temperature are usually less than +14°. However,
* Italic numbers in parentheses refer to Literature Cited, p. 54.
4 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
the spread between the temperature of the refrigerant and that of
the room is more important in maintaining humidity than in pre-
venting fluctuations in the room temperature. This point is dis-
cussed in more detail on page 5. Storage rooms should be equipped
either with reliable, accurate thermostats or with means for manual.
control which are given frequent personal attention by someone
charged with that duty. Even when reliable automatic controls are
used, they should be checked periodically by some responsible
person.
In commercial cold-storage rooms thermometers are usually placed
at a height of about 5 feet, sometimes slightly lower, for conven-
lence in reading. It is important, however, to take temperatures
frequently at the floor and the ceiling also, and at any other places
where they might be expected to be undesirably high or low. In
providing recommended temperatures for given products, considera-
tion should be given to differences between the temperatures of the
air at the position of the thermometer and at different places around
the packages of the stored product, and also to differences between
air and commodity temperatures. Often the packages are piled too
closely together or distribution of refrigeration is inadequate to reach
all parts of the piles of the stored commodity, and it is not unusual
under such conditions to have commodities remain for several days
or even weeks at temperatures several degrees higher than those in-
dicated by the thermometer. ‘This condition can be detected by open-
ing the pile and taking commodity temperatures and can be cor-
rected by wider spacing of packages and the use of portable fans
and bafiles for the direction of air currents to the centers of the
piles. The installation of such equipment will also be useful in pre-
venting dead-air pockets that are hard to cool, especially in rooms
cooled by direct-expansion coils or by brine coils and without means
for air circulation. .
The importance of maintaining fairly constant temperatures in
cold-storage rooms lies in the effect of such control, or the lack of it,
on the keeping quality of stored commodities. Most varieties of
apples keep best and longest if held constantly at 30° to 32° F.; the
best temperature for Bartlett pears is between 29° and 31°. If the
air temperature where either of these fruits is stored rises 2° or 3°
above the upper limit mentioned, there is danger of increased decay
and undue ripening, the danger being greater the longer the period
during which the temperature is above 32°. For example, 3 or 4
days at 35° usually would have little or no effect, partly because of
a slower rise in the temperature of the fruit than in that of the air;
‘but 10 days at this temperature would probably shorten the life of
the fruit by about a week and possibly result in more decay. On the
other hand, if the temperature goes a degree or two below 29°,
there is a chance that freezing will occur. Celery and cabbage al-
‘lowed to remain too warm in storage may show yellowing and decay;
potatoes are likely to begin to sprout if the temperature is too high
and usually become undesirably sweet if it is too low. Other com-
modities undergo these or other kinds of deterioration if the tem-
perature variations throughout long storage periods exceed the limits
given for them in this circular. In addition, there is always the
possibility that fluctuations in temperature will cause condensation
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS § ~-
of moisture on stored products, which in itself is undesirable because
it favors the growth of mold and the development of decay.
Control of temperature is usually easier in large rooms than in
small ones if both are filled to capacity. This is because of the “‘fly-
wheel” effect produced by the larger mass of material, including
both the commodity and the building material. Refrigeration is thus
stored up, so to speak, and the temperature changes occur more slowly.
For this reason small storage rooms generally will require closer
attention than large ones.
Humiupity oF STORAGE Rooms
The relative humidity of the air in storage rooms has a direct
relation to the keeping quality of the products held in them. With
only a few exceptions (see especially onions), the most desirable con-
dition is that in which the humidity of the air in the storage room
is kept at approximately the moisture content of the produce stored
therein. If it is too low, wilting is hkely to occur in most fruits,
vegetables, cut flowers, etc.; if it is too high, it favors the develop-
ment of decay, especially in rooms where there is considerable varia-
tion in temperature. The exact control of humidity is rather diffi-
cult, however, and in the past was not often attempted in commercial-
storage warehouses. However, at the present time new plants are
being designed and old ones changed over in such a way that a foun-
dation for humidity control in cold storage is being developed.
Sufficient refrigeration, whether coils or brine spray, is provided so
that the room can be operated with only a small difference in tem-
perature between the refrigerant and the air of the room, thus rais-
ing the dew point of the air and its relative humidity. This permits
the maintaining of high humidity. For low humidity the tempera-
ture of the refrigerant is lowered. To build up humidity quickly
in cold-storage rooms some operators evaporate water from insulated
open-top tanks equipped with insert electrical heaters. Others use
a fan to beat water into very fine particles and to blow this spray
into the room. ‘These humidifiers are sometimes made automatic,
connecting with humidistats. However, if the coil temperature is
too low, that is, if the spread between the temperature of the refrig-
erant and that of the room is too great, the effect of these various
measures will be short-lived. The relative humidity will soon become
undesirably low, and harmful drying out of the stored product will
occur.
When warm_products are placed in a cold room the spread between
commodity temperature and refrigeration temperature is wide at
first. Such a condition hastens cooling and shortens the time during
which undesirable changes can occur in the commodity. As the
spread is reduced, the cooling proceeds more and more slowly.
Eventually, if the temperature of the refrigerant is properly adjusted
and there is adequate refrigerated surface, the desired temperature
can be reached without subjecting the commodity to excessive desic-
cation. If it could be successfully managed under commercial con-
ditions, a temporary reduction in refrigerant temperature below what
is desired or safe for long-time operation would be extremely helpful
in shortening the initial cooling period,
6 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
Operators of certain large cold-storage houses have found that
when a room is filled with apples or celery, for example, the relative
humidity soon becomes constant at a fairly definite level, which for-
tunately is about the optimum for the particular commodity con-
cerned. The same result has been observed with other commercially
important fruits and vegetables and probably is obtained in many
of the larger well-constructed cold-storage warehouses of the country.
This is probably due to the fact that when a storage room is nearly
full and there is comparatively little air space left the pull on the
moisture in the produce is less, and it is easier to maintain the desired
humidity. In these cases, however, it must be assumed that the spread
between coil temperature and air temperature is kept narrow.
For most fruits that are stored commercially the statement is true
that a relative humidity of 80 to 90 percent gives the best results.
Exceptions are discussed at various places in the text. For leafy
vegetables and root crops the relative humidity should be about 90
to 95 percent; for other vegetables, except as noted in the text, 85 to
90 percent. If it seems necessary to increase the relative humidity
in rooms used for common, or air-cooled, storage, this can best be done
by sprinkling the floor occasionally. Earth floors are more desirable
in air-cooled storages than floors of concrete because they are more
easily kept damp. An increase in air circulation calls for an increase
in relative humidity if wilting of the stored commodity is to be
avoided. Allen and Pentzer (2). found that doubling the rate of air
movement increased moisture loss by about one-third and was equiva-
lent to about a 5-percent drop in relative humidity. The drying effect
of increased rate of air movement is particularly marked if the hu-
midity of the air is lower than the moisture content of the commodity.
EvoLuTIOoN oF Heat py CommopitTy
In any consideration of the storage of fresh fruits and vegetables,
cut flowers, etc., it should be remembered that these commodities are
alive and that by virtue of that fact they carry on within themselves
many of the processes characteristic of all living things. Unless the
relative humidity is high, they give off moisture to the surrounding
air and most of them, in time, become shriveled or wilted, even at
32° F. The enzymes, or ferments, they contain act on various sub-
stances in their tissues and gradually bring about changes in color,
texture, and chemical composition which ripen the commodity and
may result in serious deterioration or even complete break-down.
The most important of these changes are produced by respiration,
the process in which the oxygen of the air is combined with the carbon
of the plant tissues, occurring chiefly in sugars, to form various de-
composition products and eventually carbon dioxide and water. -Dur-
ing this process energy is released in the form of heat, the amount
of which varies with the commodity and increases as the temperature
increases, up to about 100°. This heat is always a part of the re-
frigeration load which must be considered in handling fruits, vege-
tables, and cut flowers in cold-storage rooms or refrigerator cars.
The approximate rate of evolution of heat by various commodities is
given in table 1.
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS STOCKS if
Taste 1.—Approximate rate of evolution of heat by certain fresh fruits
and vegetables when stored at the temperatures indicated
Heat evolved per | Litera-
C dit Temper-| ton of fruits or ture
CO UN ature | vegetables per 24 | refer-
hours ¢ ence
oars Bates
adbte | 32 1, 500
Yellow Dnansparent 22. 2-4 ue ab 2 oom (°)
70 12) 380
32 700 to 800
a Ouraeas laren 2 Cire cpr ae er etn Weare eee 40 820 to 840
60 2,610 to 3,470 || os,
32 300 to 320
AYU OUSISEE la pe ir eae ty aad uae 40 590 to 600
2 60 2, 270 to 2, 350
ananas: 54 3. 300
Cike ein = ape ee ee eee { 68 8 360
Rania ge a A 68 9,240 |f (62)
Jet OSes SE salut ti Aa erg er ere 68 8, 360
Beans, lima: ae Fe aan
IRGTHG| CCY0)| ess Hes oe Raa ese (6 crea Ae 60 21, 990 (°)
70 29, 220
32 3. 160
Variety, unknown0gs Ss. 3 as se oe Ap sek re
70 37, 120
Beans, snap: ti > eae
Stringless flat-podded_____._...____- 60 39° 090 (°)
70 45, 370
39 5, 500
BlackpVielembines 2220 shin ee oo oll ab rin Be
70 52, 950
32 6, 160
StiringlesstGreen Pod! 9221. fk =. 1) ap ni oe @
80 49, 590
32 2) 650
IBeetsn (Cope dass van ae Ne ahs 40 4, 060 (2)
60 7, 240
32 7, 450
Broccoli (variety unknown)____________ an aS! a €2)
70 47, 340
32 1, 200
Cabbage (Globejus (en 8) las 1 a NETO
70 6, 120
32 1, 320
Cantaloupsy (Turlock) s-20 2 1 Ve 40 1, 960
60 8, 500 (2)
32 2, 130
DALEOES | CCOPIEE) ees tee so Meee ts eg ah PI Be 40 3, 470
60 8, 080
32 1, 620
Celery (New-York white): _-2_@2_2__2_ a a aan (¢)
70 14, 150
See footnotes at end of table, p. 9.
§ CIRCULAR 278, U. 8. DEPARTMENT OF AGRICULTURE
Taste 1.—A pproximate rate of evolution of heat by certain fresh fruits
and vegetables when stored at the temperatures indicated—Con.
Commodity
Gherriess(Sour)22 2 a Ea ee ae
Cranberries:
Harly Black 2—_= == — pe cette ao AEN So
Cucumbers (Producer and Wanchula) __-
Grapelrul the ene ee sg
Grapes:
Concord mies Ao 2 eevarbiee ie ee
Cornichon and Flame Tokay _-__-_--__-
Sultaainae se eke a Pe.
Lemons? Giurekae. 2 225 _ a) ta ee
Wet hice sb eee ee AF Be Rae eS oN = Se are ote
Mushroomsi(cultivated)-< == 222
Onions (VellowsGlobe) 2.2522 Sees se
Oranges?) BRR ek tt ye I |
Peachest#at i ts es tee ee
Pears (Bartletweo* =e eee ee
See footnotes at end of table, p. 9.
SS 8 a LLL SSS S566 SSS
Temper-
ature
Heat evolved per
ton of fruits or
vegetables per 24
hours ¢
Bote us
1, 320 to 1, 760
11, 000 to 13, 200
600
870
1, 800
720
970
1, 650
1, 690
2, 550
10, 460
460
1, 070
2, 770
4,180
602
1, 170
3, 487
8, 481
660 to 1, 100
2, 200 to 2, 640
5, 500 to 6, 600
430
1, 050
1, 690
350
850
1, 810
300
740
1, 570
580
810
2, 970
6, 200
1320
15, 990
45, 980
6, 160
22, 000
58, 000
660 to 1, 100
1, 760 to 1, 980
3, 080 to 4, 180
690 to 900
1, 400
5, 000
8, 000
850 to 1, 370
1, 440 to 2, 030
7, 260 to 9, 310
17, 930 to 22, 460
660 to 880 |
8, 800 to 13, 200 |
Litera-
ture
refer-
ence
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STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 9
Taste 1.—A pproximate rate of evolution of heat by certain fresh fruits
and vegetables when stored at the temperatures indicated—Con.
Heat evolved per | Litera-
i Temper-| ton of fruits or ture
Commodity ature | vegetables per 24 | refe-
hours ¢ ence
Sea Jaxmtiavyr
32 8, 160
Peas: 40 13, 220
TnmpOrONe Gee AO Ge. see Sp eee SS oe Se 60 39, 250
80 75, 500
32 8, 360
: 40 16, 020
Gat ONEN A fy A Se ee NS Le | 60 44, 510
80 82, 920 (4)
{ 32 2, 720
ED PETS: oo eee pores tee a oe Some 40 4, 700
(ok 260 8, 470
32 440 to 880
Potatoes @nrishyCobbler) 2.27 = 2s 40 1, 100 to 1, 760
70 2, 200 to 3, pao
: 36 4, 400 to 6,
Raspberries - - - - --------------------- { 60 | 15, 400 to 17, 600 \ Cy)
] 32 4, 240
Spinach: 40 7 850
Bloomsdale*Savoy£s Lest) sia a 50 17, 940
60 38, 000 (")
32 4, 860
Stes HAG 11, 210
Vili CIM AVON ok ya 6 2 eae. hey Te | 50 20. 640
60 36, 920
32 2, 730 to 3, 800
Sirawbertes 2) 22 74 babe ieee a 1 Senne oN (34)
80 | 37, 220 to 46, 440
Sweet corn (Golden Bantam cross; not ti e aoe
husked) ---~----------------------- Goole 38, 410
80 61, 950
Sweetpotatoes (Nancy Hall): | 32 2, 440
INTOER CUT CCS ee aee ts BENIN AAS RR ASIY ON aie 8 40 3, 300
[Pee 60 6, 300
32 1, 190
OO [=a A eee om eee ie 28 ges eee | 40. 1, 710
60 4, 280 (2)
Tomatoes: 32 580
Niaturevoneen tt B= iyi Ge Fiver so ork 40 1, 070
60 6, 230
32 1, 020
J XD) OB) ek eat eal te a ep Ma gee 40 1, 260
60 5, 640
32 1, 940
Munmipse (copped) =... a5 fe ne ee 40 2, 150
60 5, 280
2 The figures in this column were obtained (1) by assuming that the heat lib-
erated by respiration is produced by the respiration of a hexose sugar, and (2) by
multiplying the milligrams of carbon dioxide produced per hour by each kilo-
gram of respiring material by the factor 220.
’ Unpublished work by T. M. Whiteman.
¢ Unpublished work by Morris Lieberman.
4 Unpublished work on the respiration of vegetables by R. C. Wright and
T. M. Whiteman.
¢ Unpublished work.by W. T. Pentzer.
f Unpublished work by D. H. Rose and M. H. Haller.
829965—49——2
10 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
It will be noted that lettuce, Bartlett pears, peaches, and cherries
have a much higher respiration rate than potatoes, apples, and onions.
- This means that the first group require considerably more refrigera-
tion than the second to keep them at a specified temperature. Less
pronounced differences occur between other commodities in the list
and are important to a lesser degree in determining the amount of
refrigeration necessary to cool them and keep them in sound, usable
condition.
It is interesting to note that the storage life of apples (as repre-
sented by the three varieties with short, medium, and long storage
périods, table 1) varies inversely as the rate of evolution of heat. The
same relation holds true if one considers broccoli, lettuce, peas, spinach,
and sweet corn in comparison with carrots, onions, storage varieties
of grapes, and potatoes.
It is difficult to determine the heat to be removed in cooling fruits
and vegetables to cold-storage temperatures. This depends mainly
on the following factors: The specific heat of the product, the rate
at which it produces heat (by respiration), and its initial and final
temperatures. If the product could be cooled to the storage tempera-
ture instantaneously, the heat to be removed would be only the num-
ber of British thermal units (B. t. u.) or calories obtained by multiply- |
ing the specific heat of the product by the difference between the
initial and the final temperature, and this result by the weight of the
product in pounds or kilograms. This is usually called the sensible
heat. The cooling process, however, requires time, and during this
interval additional heat is produced by the respiration of the stored
fruit or vegetable.
In order to determine the amount of this additional heat it is
necessary to know the rate of heat production at any temperature
and the length of time the product is in each temperature range. For
example, if the respiration rate (or rate of heat production) for a
given commodity is twice as great at 70° F. as at 50°, the number
of hours this commodity is at each of these temperatures must be
known before the total heat produced can be calculated. When fruits
and vegetables cool, the rate at which they produce heat decreases,
and the total heat produced depends not only upon the time required
for cooling but also upon how long the commodity stays in each tem-
perature range.
Table 2 shows the approximate amounts of sensible heat and of
heat produced by respiration which must be removed from eight
varieties of five kinds of fruit in cooling them from various tempera-
tures to a temperature of 35° F. These figures are based on experi-
mental determinations of the rate of respiration at various tempera-
tures; some of the data are from the tables given by Magness and his
associates (53, 55), and the remainder from data reported by Haller |
etal. (34). The figures for Bartlett pears are based on the maximum
values given by Magness and Ballard (53). The figures given in
this table have been obtained by assuming that the heat of respiration
is produced by oxidation of a hexose sugar and can be calculated from
the rate of production of carbon dioxide, which has been determined
experimentally; very few calorimetric measurements of heat produc-
tion by fruits and vegetables have been made, and this assumption
seems to be the best available basis for calculating heat production at
11
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS
any given temperature. Recent investigations (30) indicate that cal-
culations made on this assumption give values that are within 10 per-
cent of those obtained calorimetrically.
The assumption has also been made, although it is believed to be
only approximately correct for fruits and vegetables, that the rate
of temperature drop at any given time during cooling is proportional
to the difference between room temperature and fruit temperature
at that time. With this assumption as a basis, the temperature and
thus the rate of respiration at any time during the cooling period, as
well as the total heat produced during the whole cooling period, have
been calculated. *
TasLEe 2.—Approximate amounts of heat of respiration and sensible
heat to be removed from certain fruits in cooling them from 60°, 70°,
or 80° to 35° F. in a room at 32°, when the cooling takes place in
3, 4,5, 6,8, or 10 days
Initial| Heat of respiration per ton of fruit during—
Sensi-
Kind of fruit a ble
ture |3 days|4 days/ 5 days|6 days] 8 days | 10 days heat !
CORES ESE FRU SSIEA URIS CALs Dt bs UL Lee be Ue Bit! we: €b-
Apples: 80] 8, 000]11, 000)14, 000|16, 000] 22, 000] 27, 000/80, 000
Wanesapet. -= 70| 7,000} 9, 000/12, 000/14, 000} 19, 000} 23, 000/62, 000
60] 6, 000) 8, 000/10, 000/12, 000) 16, 000} 20, 000/44, 000
[ 8012, 000/16, 000|20, 000/24, 000] 32, 000] 40, 000/80, 000
Grimes Golden__|; 70/10, 000/13, 000/17, 000/20, 000] 26, 000] 33, 000/62, 000
Leap 8, 000/11, 000/13, 000/16, 000) 21, 000) 27, 000/44, 000
Peaches: 80/13, 000/18, 000/22, 000/26, 000] 35, 000] 44, 000/80, 000
Hibertate 2 ow 70/10, 000}13, 000/17, 000/20, 000] 26, 000] 33, 000/62, 000
60| 7, 000/10, 000/12, 000/14, 000] 19, 000] 24, 000/44, 000
80/16, 000/22, 000/27, 000/32, 000] 43, 000] 54, 000/80, 000
@armam.20 4. 70/13, 000/17, 000/21, 000/25, 000] 34, 000} 42, 000/62, 000
pee: 60/10, 000/13, 000/16, 000/19, 000} 25, 000} 32, 000/44, 000
“Ba, jae i 70/16, 000/22, 000/27, 000/33, 000] 44, 000} 54, 000/61, 000
Ae ae ara 60/13, 000/17, 000/22, 000/26, 000] 35, 000} 43, 000/43, 000
Strawberries: { 80/30, 000/39, 000/49, 000/59, 000! 79, 000} 99, 000/83, 000
Chesapeake _-_ _-_- 70|24, 000/32, 000/40, 000/49, 000] 65, 000} 81, 000/64, 000
ee eo 19, 000/26, 000/32, 000/39, 000} 51, 000) 64, 000/46, 000
80/38, 000/51, 000/64, 000/77, 000)102, 000/128, 000/83, 000
Howard 17_____- 70/31, 000/42, 000/52, 000/63, 000] 84, 000/104, 000/64, 000
Oranges: 60/25, 000/34, 000/42, 000/51, 000} 68, 000} 84, 000/46, 000
Florida seed- 80] 9, 000/12, 000/15, 000/18, 000} 24, 000} 30, 000/81, 000
linge Se. 70| 8, 000/10, 000/13, 000/15, 000] 20, 000] 26, 000/63, 000
60] 6, 000! 9, 000/11, 000/13, 000] 17, 000} 22, 000!45, 000
1 For any one kind of fruit at a given temperature these figures are assumed to
be the same for all cooling periods included in the table.
2 The rate of respiration is practically the same for both Florida seedling oranges
and California navel oranges.
*The authors wish to acknowledge the valuable assistance given by W. V.
Hukill, Division of Farm Buildings and Rural Housing, Bureau of Plant Industry,
Soils, and Agricultural Engineering, in making the calculations and in preparing
this statement on the production of heat by fruits and vegetables.
12 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
As a result of these calculations it has been found that the heat
produced by the respiration of fruit while it cools is directly pro-
portional to the length of the cooling period. The figures for cool-
ing periods of 3, 4, 5, 6, and 8 days are therefore set at 0.3, 0.4, 0.5, 0.6,
and 0.8 (to the nearest thousand) of the figure for 10 days. The spe-
cific heat has been calculated by the formula S=0.008a@ + 0.20, in
which S signifies the specific heat of a substance containing a percent
of water; 0.20 is the value that has been assumed to represent the
specific heat of the solid constituents of the substance in question (88).
Column 1 of table 2 shows the kind and variety of fruit and col-
umn 2 the temperature of the fruit at the time cooling started, in a
room held at 32° F. The next column shows the amount of heat
evolved by respiration if the fruit reaches 35° at the end of 38 days.
The next five columns show the amount of heat if cooling to 35° re-
quires 4, 5, 6, 8, or 10 days, respectively. ‘The last column is the
sensible heat (obtained by multiplying the specific heat of the fruit
by the difference between initial and final temperatures and this
result by the number of pounds in a ton).. For any one kind of
fruit at a given initial temperature, the specific heat is assumed to be
the same for all the cooling periods included in the table.
The values given in table 2 are only approximate. However, in
view of the results of the investigations mentioned on page 10, it is
believed that the two assumptions that have been made—namely, (1)
that the heat of respiration is produced only by the oxidation of a
hexose sugar and can be computed from observed amounts of carbon
dioxide produced and (2) that the rate of temperature drop is always
proportional to the difference between fruit temperature and room
temperature—probably lead to fairly accurate results. The figures
are presented to help cold-storage-plant operators estimate the refrig-
eration required for cooling the specified fruits under the various
conditions given. As an example of how the figures can be used,
the following calculation may be of interest: A ton of Bartlett pears
cooling from 70° to 85° F. in 10 days in a 32° room is shown to be
capable of producing about 54,000 B. t. u. Its sensible heat at 70°
(35° above its final temperature) is 61,000 B. t. u. The sum of the
two is 115,000 B. t. u. If this be multiplied by the capacity of the
room in tons of fruit, say 600 (the capacity of some of the commercial
cold-storage rooms in the United States) and divided by 288,000 (the
number of British thermal units in a ton of refrigeration), the quo-
tient 239 is obtained; this is approximately the number of tons of
refrigeration required to cool 600 tons of Bartlett pears to 35° in
10 days under the conditions specified. The corresponding figure for
Winesap apples is 177 and that for Grimes Golden apples 200.
EFFECT OF COLD STORAGE ON SUBSEQUENT
BEHAVIOR OF FRUITS AND VEGETABLES
The belief is rather common among those concerned with the mar-
keting of fresh fruits and vegetables that commodities of this kind
that have been in cold storage deteriorate more rapidly after removal
from the low temperature than if they had been held at ordinary
temperatures. It is difficult, however, to find a basis for judging
whether or not they actually do so because there is no means known
other than the use of low temperature for checking the ripening and
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 13
decay so largely responsible for their deterioration—that is, it is
impossible in the present state of knowledge to obtain fruits and
vegetables that have not been refrigerated but still have not changed
in any way since harvest, for comparison with similar lots that have
been in cold storage and are eventually removed. However, so far
as is now known, it is correct to say that for many fruits and vege-
tables cold storage at or near 32° I’. is beneficial. Important excep-
tions are bananas, sweetpotatoes, tomatoes, cucumbers, melons, and
certain other horticultural products mentioned herein, the behavior of
all of which in storage is discussed later under appropriate headings.
SWEATING
When fruits or vegetables are removed from a low temperature to
a higher one there is frequently a condensation of moisture from the
air on the cool surface of the commodity. This is known as sweating
and is more marked the higher the relative humidity of the outside
air. It should be prevented whenever possible in the case of onions
and the more tender fruits, because it favors the development of decay.
This does not mean that when any of these products sweat after
removal from an iced refrigerator car or a refrigerated room they
are sure to decay; it does mean that they are more hkely to decay
than if they were dry after being unloaded and remained dry until
consumed. In this connection dryness means merely the absence of
liquid water on the surface.
Sweating can be prevented to some extent, as in the British prac-
tice with eggs and certain other commodities, by allowing the fruits
er vegetables to warm up gradually. Under commercial conditions in
the United States this is rarely practicable, however, and the best thing
to do in very damp weather is to realize the risk, handle the product:
carefully, and get 1t into consumption without undue delay.
WAXING
The application of waxing preparations to certain perishable prod-
ucts has been practiced commercially for several years. It probably
started with the waxing of citrus fruits and was followed by the wax-
ing of rutabagas. Its value for both of these products lies in the fact
that it not only improves their appearance but also prevents shrinkage
by restricting the loss of water.
Waxing has been tried on a number of other products. In the case
of cucumbers and carrots it gives considerable promise and may
come into general use. It has been tried on cantaloups but did not
prove to be beneficial.
(See 76.)
CHOICE OF STORAGE CONDITIONS
The storage conditions recommended herein for certain commodi-
ties represent either a compromise between two undesirable extremes
of temperature or humidity or a choice of the least harmful of two
such extremes. Grapefruit, for example, suffers less from decay at
low humidities than at high; on the other hand, at low humidities.
it is subject to a pitting which, in fruit from regions where stem-
14 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
end rot is not prevalent, is usually more damaging to the market value
of the fruit, because it is more common than decay. Therefore, it is
recommended that grapefruit from all producing regions be held
at 85 to 90 percent relative humidity in storage in order to reduce
pitting.
The Jonathan variety of apple suffers less from soft scald if stored
at 34° to 86° F. than if stored at 82°. It is susceptible, however, to the
more common and more serious condition known as internal break-
down and also to Jonathan spot and decay if held continuously at
temperatures above 32°; hence this latter temperature should usually
be chosen as safer than any higher one.
Investigations in New York State (97) have shown that one lot of
apples may have a stimulatory effect on the ripening of another lot
stored with it. In some tests as much as 50 percent or more of the
storage life of a lot of apples was lost because of exposure to the emana-
tions from other apples. The agent causing the stimulation is pre-
sumed to be ethylene, but it was not identified as such. The most
effective absorbent for removing the stimulatory agent was activated
coconut-shell carbon.
Combinations that should be avoided in storage rooms are apples
with celery, cabbage, potatoes, or onions; celery with onions; and cit-
rus fruit with any of the strongly scented vegetables. Under various
commodities additional undesirable combinations are discussed.
FRUITS AND NUTS
By Dean H. Ross, senior physiologist
The recommended temperature, relative humidity, and approximate
length of storage period for the commercial storage of fresh, dried, and
frozen fruits, and nuts are given in table 3. Detailed descriptions of
these requirements are given in the text.
APPLES |
(Temperature, 30° to 32° F.; relative humidity, 85 to 88 percent)
There is a wide variation in the storage quality of the different
varieties of apples and of the same variety grown in different regions.
For example, McIntosh grown in the Middle Atlantic States is prac-
tically an early-fall apple not suitable for more than 2 or 3 weeks’
storage, whereas if grown in northern New York or New England
it can be held for as long as 4 or 5 months. Such varieties as Northern
Spy, Baldwin, and Rhode Island Greening grown in the Cumberland-
Shenandoah Valley district or in the hot, irrigated valleys of the
Pacific Northwest behave like fall varieties and are short-lived in
storage, although suitable for winter storage when grown in New
England, New York, Michigan, and other northern producing districts.
The keeping quality of apples in storage is also definitely related -
to the cultural and orchard sanitation practices of the grower, who
alone is responsible for the production of sound, properly matured
fruit. To have good keeping quality, apples should be mature and
well-colored. When they have reached this stage, they are less likely
to scald in storage and are in better condition generally to be held in
storage for the maximum period than if they are either immature or
overmature (55, 56).
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS
15
Taste 3.—Recommended temperature, relative humidity, and approi-
mate length of storage period for the commercial storage of fresh,
dried, and frozen fruits, and nuts, and the average freezing pots
f Tempera-
Commodity ies
OE:
IND DIGS! as) eee ee na 230 to 32
Atpnicoitis tents Vangt pret ax 31 to 32
ANVOCR GOS “eyes ay te pe CI (3)
Loy ae . Sea i (4)
Blackberriesso. (esse 31 to 32
Cherniese: 2 (hits fakes als 31 to 32
Coconuts etre) sere se ay 32 to 35
Cranberries. sneer 36 to 40
Dates sete ema al eel ee (4)
Dewhbenriest. 2a ae ees 31 to 32
Rigs). (fresh) eg! 35" Sex ee a 31 to 32
Grapefruitee sees 2S. (4)
Grapes:
WimMiheha cre: Soyo kaso 30 to 31
INTACT NCAT se OES 31 to 32
Hemionget ti GI La ere, ee 55 to 58
Dimes. *ellypsariy 3 ap eae ? 45 to 48
Logan blackberries_______- 31 to 32
Olives? Gresh) os see we 45 to 50
Oranges 22 2 rea (4)
Reachest page ac te ieee. 31 to 32
Pears:
IS argletgmesae enn 29 to 31
Fall and winter varieties_| 29 to 31
Pineapples:
Mature green______-___ 50 to 60
1 ats) Osc es See Stee nd a ae 40 to 45
Plums (including prunes) __| 31 to 32
Quincese eee eee et ee Sle tOroe
Raspberries hf st ai Sat 1 31 to 32
DLEAWOCITICS sap v See 31 to 32
Dricdtinuits. 28 2. ee ts (4)
Mrozem fruits= ee ee (4)
INGGS Mere See hon bees 432 to 45
Relative
humidity
Percent
85 to 90
85 to 90
80 to 85
85 to 90
85 to 90
80 to 85
85 to 90
85 to 90
80 to 85
85 to 90
85 to 90
85 to 90
'85 to 90
80 to 85
80 to-85
80 to 85
80 to 85
(*)
65 to 75
Approximate
length
of storage period
2
7 to 10 days 4
10 to 14 days_
ifto;2 imonthsuu sas
(
(tO LOl day cia ae ote ee ee
Average
freezing
point !
LO day siete aia selon OS
6 to 8 weeks_
> tO.O Months: =... 5
3 to 8 weeks 4
Lito 4mionths lie.
6 to 8 weeks-_
7 to 10 days_
4 to 6 weeks_
1 These figures are based on previously published work by Wright (116) and
are subject to revision whenever further investigation makes this necessary.
2 See text and table 4.
3 See text and table 5.
4 See text.
5 Green: Flesh, 30.2°; peel, 29.8°.
Ripe: Flesh, 26.0°; peel, 29.4°.
6 Hastern sour, 28.0°; eastern sweet, 24.7°; California sweet, 24.2°.
7 Flesh, 28.0°; peel, 27.4°.
§ Winter Nelis, 27.2°; Anjou, 26.9°.
® Persian (English) walnuts, 20.0°; pecans, 19.6°; and chestnuts (Italian), 23.8°.
To insure soundness and good keeping quality, apples must be not
only properly grown and at the proper stage of maturity, they should
also be handled in all the operations of picking, grading, packing,
and hauling with that degree of care necessary to prevent serious
bruising, skin punctures, or other mechanical injuries; and they should
be stored as quickly as possible after they are picked.
16 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
Apples should not be handled while frozen, if such handling can
possibly be avoided. Water core does not develop or spread in storage,
and in varieties such as Yellow Newtown and Winesap it may actually
disappear after a few months’ storage, especially if originally present
only in mild form. When large portions of the flesh are affected,
especially in soft-textured varieties like Jonathan, Delicious, Stayman
Winesap, and Rome Beauty, there is danger of subsequent break-down
and prompt disposal of the fruit is advisable. The diseases of apples
in storage are discussed in Farmers’ Bulletin 1160 (8) and Miscel-
laneous Publication 168 (84).
For the storage of most varieties of apples the best results are
obtained by maintaining a temperature of 30° to 32° F. and a relative
humidity of 85 to 88 percent. However, as the storage temperature
approaches the freezing point of the fruit the hazard of freezing
increases unless the temperature is well controlled and there is good
air circulation. Yellow Newtown apples from the Pajaro Valley,
Calif., and McIntosh and Rhode Island Greening apples from New
York should be held at 35° to 38° rather than at 32° to prevent the
development of internal browning or brown core. Grimes Golden
apples should be held at 34° to 36° instead of at lower temperatures
(77) in order to avoid soggy break-down. It should be remembered,
however, that at these higher temperatures the fruit cannot be held
as long as when stored at 30° to 32°, because of the possible develop-
ment of Jonathan spot and internal break-down.
(See 9, 21, 36, 43, 71, 72, 73, 74.)
If air-cooled storage is used, the temperature obtainable will usually
not be much lower than the average of the prevailing outside tempera-
tures. The nearer this is to 32° F. the better.
The length of time apples can be held successfully in cold storage
will vary with the variety and with the district where grown, as well
as with their condition when harvested. Table 4 shows the normal or
average storage period and the maximum storage period for the more
important apple varieties when picked at proper maturity and stored
immediately at 30° to 32° F.
Taste 4.—Normal and maximum storage periods for important apple
varieties
Storage period Storage period
Variety Variety
Nor- Maxi- Nor- | Maxi-
mal mum mal mum
Months | Months Months | Months
Jonathani=, 4 seeee 2 to 3 4 || Arkansas (Black
Grimes Golden__-—-_-- 2 to 3 4 Areas oS 2 SS 4 to 5 6
Mcintosh ets se sees 2 to 3 4360-51) SDeliciauste2 ae 1 eae 4 to 5 6
Golden Delicious____- 3 to 4 5 || Northern Spy__-_-_-_-- 4 to 5 6
Contlandi=* eset 3 to 4 Salli: Baldwin.) t Fie ht 4 to 5 6 to 7
Rhode Island Green- || Rome Beauty_------ 4 to 5 6 to 7
IN GY oe a ee ee 3 to 4 6") Ben’ Dawises ae ore 4 to 5 8
Stayman Winesap____| 4 to 5 5'to 6) Winesaps 252 Naito’ 8
York-lmperiales = 4 to 5 5 to 6 || Yellow Newtown_-_-_-_| 5 to 7 8
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 17
In determining when to remove apples from storage the dealer
must, of course, consider the market, but he must also allow for
the more rapid softening that takes place at the higher temperatures
to which they will usually be removed. Investigations by the United
States Department of Agriculture (55) have shown that apples soften
approximately twice as fast at 70° as at 50° F., twice as fast at 50°
as at. 40°, and about twice as fast at 40° as at 32°, whereas at 30° the
rate is about three-fourths that at 32°.
Apples in cold storage should be inspected frequently, in order
that they may be removed and sold while still in good condition.
It is highly desirable that apples intended for storage be wrapped
in oiled paper or packed in shredded oiled paper, in order to reduce
* damage by scald as much as possible (22). Apples should not be
stored in the same room with potatoes because of the danger that
the former will absorb undesirable odors. On the other hand, the
odors given off by apples are readily absorbed by dairy products;
consequently the two should not be stored in the same room. (See
also p 14.)
(See 8, 81, 90, 19.) :
APRICOTS
(Temperature, 31° to 82° F.; relative humidity, 80 to 85 percent)
Apricots are not stored commercially to any extent, although they
will keep well for 1 to 2 weeks at 31° to 32° F. When harvested at a
firmness pernitting storage and shipping, the fruit lacks flavor and
has poor dessert quality after ripening but is satisfactory for canning
purposes (7).
AVOCADOS
(Temperature, see text; relative humidity, 85 to 90 percent)
Investigations in California (63) on the storage of avocados have
shown that the best temperature for all varieties grown there, except
the Fuerte, is about 40° F. The Fuerte discolors internally at this
temperature but holds up well at 45°. At temperatures below 40°
all the varieties investigated are likely to become discolored internally
and do not soften when removed to a higher temperature. When
properly stored. the Dickinson, Royal, Taft, and Queen are said to
hold up well for about 2 months, the Spinks, Sharpless, and Challenge
for 5 to 6 weeks, and the Rey, Fuerte, and Kist for about 4 weeks.
Most of these varieties are of the Guatemalan race.
No general recommendations can be made concerning the storage of
varieties of avocados grown in Florida, Central America, or the West
Indies, because of the wide variation among them in susceptibility
to injury by low temperatures. Many varieties of the West Indian
race are injured by exposure to temperatures of 50° to 53° F. for 15
days (99, 100), whereas others (Pollock, Trapp) remain in good con-
dition for 3 weeks when held at 42° (52). Varieties of the Guate-
malan race are more resistant to cold, and those of the Mexican race
are the most resistant of all. Some of the varieties that are least
affected by cold (Lula, Taylor) can safely be held at 87° to 42° for 4
weeks (52). Wolfe, Toy, and Stahl (7/5), in their work on the storage
of Florida-grown avocados, obtained the results given in table 5.
829965493
18 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
Taste 5.—E'ffect of storage of various avocado varieties at different
temperatures on their marketable life *
<
5 ea Period
pti- erio there- : Gain in
mum | held at | after at aed market-
Variety 2 tempera-joptimum| room Ble & _| able life
ture for |jtempera-|tempera- a F SOS ihe tie
storage ture ture tons: ) eee storage
softening
|
he Days Days Days Days
Bollocks 8 ae Sn ms 42 21 3 3 17-19
‘Prapp GWab) eects Ce 42 21 ae) | 2-5 18-20
Wrallclaar: CVD) iy ie aaa sv as CB) Agee pene lca et as ae Ra re | A
Collinson <G XG Wai 42-48 14 4-6 3-4 7-8
Booth) 8 (Glo Wil) See ae see 42 14 4—6 | 1-4 7-9
Poulan G eB) baie hy ein sein cece ee 37 28 3-6 i=) 20-24
Paylor (Gye ieee a OE 37 28 4—6 | 2-3 23-26
1 Adapted from Wolfe, Toy, and Stahl (1/74). ;
2 WI, West Indian; G, Guatemalan; M, Mexican; G * M, Guatemalan X
Mexican; G X WI, Guatemalan * West Indian.
3 Cold injury noted even at 48° storage.
At the higher temperatures mentioned, in the text, anthracnose, a
fungus disease of avocados, will probably be an important factor in the
storage of this fruit. At the lower temperatures decay is not likely to
be troublesome after long storage.
BANANAS
_ (Temperature: ripening, 62° to 70° F.; holding ripe fruit, 56° to 60°. Relative
humidity: green fruit, 90 to 95 percent; ripe fruit, somewhat reduced but
not below about 85 percent)
The banana is one of the fruits that must be shipped to market
green, because in this condition it can be handled for a longer time
without becoming overripe and without serious injury from bruising
during the marketing process. Furthermore, bananas of the Gros
Michel variety, which make up the great bulk of banana shipments
into this country, if allowed to ripen on the plant become mealy, lack
flavor, and are subject to splitting, with subsequent decay.
The bunches of green bananas as they are received from the Tropics
are usually ripened at a temperature of about 64° F., with a relative
humidity of 90 to 95 percent or higher. If it is desired to hasten the
ripening process, a higher temperature can be used (up to 70°) for the
first 18 to 24 hours, but temperatures should then be reduced to about
66°. In any case the relative humidity should be kept at 90 to 95
percent or higher until the fruit becomes thoroughly colored. After
this it should be reduced shghtly, but not below about 85 percent.
Prolonged exposure to high temperatures will cause poor color and
flavor and weak necks and will hasten decay.
The lowest temperature at which green bananas can safely be held
in order to delay ripening is about 56° F.; below this they suffer an
injury known as chiling—a form of peel injury to which both green
and ripe bananas are susceptible, caused by low but not freezing tem-
peratures. Ripe fruit is slightly more susceptible to chilling mjury
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 19
than green fruit. Fruit chilled in the green stage does not develop
a bright-yellow color on ripening, but instead a smoky dull color.
Fruit chilled after ripening will develop a dull-brown color when
later exposed to higher temperatures and is very susceptible to han-
dling marks, the slightest bruising causing discoloration.
The best holding temperature for ripe bananas is generally con-
sidered to be between 56° and 60° F. At this temperature they will
retain their good appearance and flavor and remain edible for a week
or 10 days, although ordinarily they will not keep firm enough for
shipment more than half that time.
(See 25, 103.)
BLACKBERRIES
Short storage only. See Raspberries.
CHERRIES
(Temperature, 31° to 32° F.; relative humidity, 80 to 85 percent)
The extreme limit for the successful commercial cold storage of
fresh cherries at shipping point is probably about 10 days to 2 weeks.
Tt is doubtful whether fresh cherries from California and the Pacific
Northwest can be held satisfactorily in cold storage for more than
about a week after arrival at eastern markets. This would mean about
16 days from harvest. If held longer than the period indicated they
begin to lose flavor and the bright attractive appearance characteristic
of the fresh fruit. The stems may also dry out noticeably, especially
if the relative humidity is low. Color changes and decay can be
retarded by the use of carbon dioxide gas in transit (28). In fact,
the treatment has proved to be so beneficial in this respect that it is
now being used commercially for shipments of cherries from the
West and Northwest to eastern markets.
The sweating discussed on page 13 is particularly troublesome on
cherries, because of the dull appearance that it produces on the fruit
when displayed for sale soon after removal from iced cars.
CocoNuts
(Temperature, 32° to 35° F.; relative humidity, 80 to 85 percent)
Coconuts are best stored at 32° to 35° F. and can be held satisfac-..
torily within that range for 1 to 2 months. !
~ CRANBERRIES
(Temperature, 36° to 40° F.; relative humidity, 85 to 90 percent )
A. large part of the cranberry crop is held at the bog every year
until wanted for Thanksgiving and the Christmas holidays. When
so held it is usually kept either in common (air-cooled) storage or in
artificially refrigerated warehouses. The storage period is usually
not longer than about 3 months and for that length of time the range
from 36° to 40° F. (whether obtained in air-cooled storage or under
artificial refrigeration) has been found to be the most desirable.
Occasional lots of poorly colored fruit may be held at 45° to 50° for a
few weeks in order to permit more rapid coloring than would occur
at lower temperatures. Storage for more than about 4 months, in the
20 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
range from 36° to 40°, is not satisfactory because of the common
occurrence of end rot, a fungus disease, which can develop at low
temperatures (J/8). Shrinkage of the berries as a result of water loss
is also a limiting factor. Further facts that need to be kept in mind
are that keeping quality depends to some extent on the maturity of
the fruit, that some varieties keep better than others, and that there
may be a difference in keeping quality from year to year in crops
from the same bog.
Cranberries for long-time storage are best held “in the chaff” in
the picking crates as they come from the field. Thus handled they
keep better than if sorted and cleaned previous to storage.
Cleaned and sorted cranberries can safely be stored at the market
for 5 to 8 weeks if held at a temperature of 32° F., but fruit held for
a longer time at that temperature is likely to develop a “low-temper-
ature break-down.” Berries in this condition are “rubbery” when
pressed between the fingers, the flesh is permeated with red pigment
from the skin, and some of the natural luster has disappeared. Such
berries closely resemble those that have been frozen. Fruit held at
36° to 40° is less likely to discolor and become rubbery, but if it has
been cleaned and sorted it is more likely to suffer from decay than if
held at 32°.
(See 4, 23.)
DatTEs
(Temperature, see text; relative humidity, 65 to 75 percent; or 28° F. and no
humidity control for cured grades)
Dates absorb moisture and odors readily from the air. The rate of
absorption is much less at temperatures below 32° F. than at those
above 32°. Deterioration caused by humidity above 75 percent is
slow at storage temperatures below 28°. The dates of commerce are
of three grades with respect to storage life—dried, cured, and non-
cured. The cured and noncured grades are perishable. A tempera-
ture as low as 0° has no deleterious effect upon dates but is actually
beneficial to them.
Dates are of two different types, and fruits of each type are likely
to be either dry, cured, or noncured. The cane-sugar type is usually
firm, light-colored, and comparatively dry, whereas the invert-sugar
type is usually softer, darker colored, and inclined to be shghtly sticky
or sirupy.
Deglet Noor, the most important variety grown in this country, is
of the cane-sugar type. Dates of this variety, cured grade, keep well
until March at 28° to 32° F. and for a year at 24° to 26° or lower,
whereas the noncured grade requires 18° or lower for storage until
March and 0° to 10° for a year. In Deglet Noor dates that have be-
come overripe or have been held under unfavorable storage conditions
the cane sugar is inverted and the dates become soft, sirupy, and
darker in color. Such dates are commonly graded as “dark soft.”
If they can be dried down somewhat, they can be stored at 28° to 32°
until Christmas without becoming objectionably dark and sirupy,
although a temperature of 0° to 10° will be needed if they are to be
stored until March. If such dates are not cured, a temperature of
0° to 10° is necessary for even short-time storage (39).
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 21
Halawy, Khadrawy, Zahidi, and Saidy dates are all of the invert-
sugar type, and the cured grades can be kept until Christmas at 25°
to 32° F. without forming sugar spots but require a temperature of
18° or lower if stored until March. Noncured grades of these varieties
require 0° to 10° for even short storage. After Christmas it is well
to shift all dates of the invert-sugar type remaining in storage to
“freezers” at 0° to 10° (4).
DEWBERRIES
Short storage only. See Raspberries.
Fics (FREsH)
(Temperature, 31° to 32° F.; relative humidity 85 to 90 percent)
Fresh figs in storage require a temperature of 31° to 32° F. and a
relative humidity of 85 to 90 percent, but even under these conditions
they cannot be expected to keep satisfactorily for more than about 10
days.
GRAPEFRUIT
(Temperature, see text; relative humidity, 85 to 90 percent)
Storage rooms for grapefruit should have a relative humidity of 85
to 90 percent. Lower humidities are favorable to pitting, and higher
ones may increase decay.
For short-time storage, grapefruit can be held satisfactorily at a
temperature of 32° F. For longer periods the temperature to be used
will depend on the character of the fruit and the troubles most likely
to be encountered. For fruit grown in sections where stem-end rot
is prevalent, this disease is likely to be the determining factor; it will
generally be advisable to use a comparatively low temperature range
(32° to 34°). On the other hand if the fruit is grown in sections
where stem-end rot is not prevalent, the limiting factors are likely to
be storage pitting and watery break-down, which develop most seri-
ously at temperatures of 40° or lower. For fruit from these sections a
temperature of 45° to 55° is satisfactory, and the more rapid develop-
ment of undesirable high color and the increase in blue mold and green
mold rots at the higher temperatures have not been found as objec-
tionable on such fruits as the pitting that results from storage at lower
temperatures.
Sound fruit that is not overmature or likely to suffer from stem-
end rot can usually be held for 6 weeks without serious spoilage at
the higher temperature mentioned above, and this storage period can
sometimes be doubled with satisfactory results. Weak or overmature
fruit requires close watching from the time it is removed from the
tree, regardless of storage conditions.
The percentage of stem-end rot in Florida and Texas grapefruit
will be greatly reduced if the fruit is properly treated with borax or
sodium metaborate, pulled from the tree instead of being clipped
(112), and precooled before being shipped. ‘The disbuttoning that
may occur during handling and packing is also effective in reducing
loss from stem-end rot. As compared with stem-end rot, blue mold
and green mold rots are relatively less important on Florida grape-
22 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
fruit in storage. Stem-end rot is not known to occur on California
and Arizona grapefruit. _
(See 10, 24, 92, 93, 94, 111, 112, 113.)
GRAPES
VINIFERA
(Temperature, 30° to 31° F.; relative humidity, 85 to 90 percent)
Large quantities of the European, or vinifera, grapes, grown princi-
pally in California, are stored every year. The most important of the
varieties stored are Emperor and Ohanez (Almeria). Olivette de
Vendemian, Malaga, Sultanina (Thompson Seedless), Cornichon, and
Alphonse Lavallee (Ribier) are also occasionally stored. Al] of these
have low freezing points, lower in fact than the freezing point of any
other important fruit, largely because of their high sugar content.
Although for most varieties there is no danger of freezing injury at
temperatures as low as 28° F. (73), they are usually held at tempera-
tures of 30° to 31°. At low air velocities a humidity of 85 percent
prevents excessive wilting of stems and berries without favoring the
formation of mold growth. At air velocities of 100 to 150 feet per
minute a humidity of 90 percent is desirable (2, 67).
California grapes for cold storage are packed in kegs or drums in
sawdust or in various types of lidded lugs with or without sawdust.
Good results are usually obtained, although if the fruit or the sawdust
is damp at packing time or becomes so in storage there is danger of
damage by mold. Mold may develop also if the grapes have been
handled carelessly and if there are numerous cracked or loosened ber-
ries scattered through the pack. Varieties differ in keeping quality.
The best storage varieties when properly handled can be held 3 to 6
months in storage at 30° to 31° F. Emperor, Ohanez, and Alphonse
Lavallee (Ribier) seem to keep better than any of the other storage
varieties. Treating grapes with sulfur dioxide has helped to reduce
spoilage in storage. In recent years the display type of lug has
grown in favor for storage, because grapes packed in it can be re-
fumigated. The common practice is to fumigate with concentrations
of about 1 percent of sulfur dioxide before storage and to refumigate
with about 0.2 percent of the gas at intervals of 10 days. Under these
conditions fruit has been held fully as long in this type of package as
in the more expensive sawdust chests or kegs. When fruit packed in
display lugs cannot be refumigated in storage, 5 grams of sodium
bisulfite is often added to the pads before packing, and this is fol-
lowed by the usual prestorage fumigation. Mixing 5 grams of
sodium bisulfite (per lug, chest, or keg) with the sawdust used in
packing grapes has also been effective in checking decay (66).
Storage quality varies considerably from season to season and
seems to be adversely affected by rain just before and during harvest.
Grapes picked before rains usually keep better than those picked after
rains. :
(See 73, 65.)
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 23
AMERICAN
(Temperature, 31° to 32° F.; relative humidity, 80 to 85 percent)
The eastern, or American, varieties of grapes, the most important of
which is Concord, are not adapted to long storage; and most of them
do not hold up well under storage conditions for more than 3 or 4
weeks, depending on the variety. After that time they begin to
deteriorate in flavor and may suffer heavily from decay if the temper-
ature is not kept close to 32° F. The Catawba keeps better than most
other eastern varieties and, if in good condition when stored, can be
held for 3 to 8 weeks even in common storage in the districts where
this variety is grown on a commercial scale.
Too low humidity is undesirable for grapes, since it causes shrivel-
ing, especially of the stems. Stock intended for storage should be
handled carefully to avoid cracking of the berries or loosening at the
cap stem, because such injuries allow juice to exude and thus furnish
favorable conditions for the beginning of decay.
Muscadine grapes are shipped only short distances if at all and are
not known to be held in cold storage anywhere in commercial quan-
tities. |
(See 2, 48.)
LEMONS
(Temperature, 55° to 58° F.; relative humidity, 85 to 90 percent)
From the standpoint of preventing decay (blue mold rot, green
mold rot, and alternaria rot) in stored lemons, the lowest temperature
that can be used without freezing the fruit would seem to be the most
desirable. The difficulty is that at low temperatures certain non-
parasitic troubles which are fully as serious as decay develop; among
these are red blotch, pitting, and membranous stain. With proper
humidity and at temperatures above 50° F. red blotch and pitting
practically never occur and membranous stain is greatly reduced.
The best results are usually obtained by storage at 55° to 58° in a
relative humidity of 85 to 90 percent. Under such conditions lemons
can be expected to hold up satisfactorily for periods of 1 month to
as long as 4 months, depending on their maturity and condition when
stored (77). ‘Tree-ripened lemons, which are yellow when picked,
do not keep well in storage.
It is of the utmost importance that lemons be handled carefully
during picking and packing in order to avoid clipper cuts, scratches,
and bruises and consequent damage later by green mold rot and blue
mold rot. The fungus that causes the latter is able to penetrate the
uninjured skin of lemons but is likely to cause more loss if the skin
of the fruit is broken at numerous places. It can also spread from
one fruit to another in the package and for this reason is frequently
referred to as “blue contact rot.” Air conditioning as now used in
some of the lemon storage houses in California furnishes a means of
preventing condensation of moisture on fruit and so decreases the
danger of decay.
Lemons and other citrus fruits should not be stored in the same
rooms with dairy products because of the readiness with which the
latter absorb odors. (See also p. 14.) Lemons in storage should be
24 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
examined frequently to avoid loss from the development of decay or
other deterioration.
(See 11, 16, 39, 42.)
LIMES
(Temperature, 45° to 48° F.; relative humidity, 85 to 90 percent) _
Preliminary investigations with Tahiti (Persian) limes indicate
that fruit from a well-kept grove may be stored satisfactorily at a
temperature of 45° to 48° F. for 6 to 8 weeks, provided that the rela-
tive humidity is kept above 85 percent or the fruits are wrapped
so as to prevent moisture loss. Prevention of desiccation is very
important. For best quality, the Tahiti lime should be picked while
still green but after the fruit has become “full” and smooth, having
lost the “dimpled” appearance around the blossom end.
Key (Mexican, or Dominican) limes can be stored satisfactorily at
the temperatures recommended for Tahiti limes. The preferred color
for this variety on the markets of the United States is yellow.
Temperatures above those recommended permit the development
of stem-end rot, which is often a serious factor in the marketing of
limes from Florida and the West Indies.
LocGAN BLACKBERRIES
Short storage only. See Raspberries.
Ottves (FREsH)
(Temperature, 45° to 50° F.; relative humidity, 85 to 90 percent)
The best storage temperature for fresh olives (67) les between
45° and 50° F., and the safe storage period is 4 to 6 weeks. At lower
temperatures the flesh of green fresh olives becomes brown, beginning
around the seed and at the stem end. Ripe fresh olives develop more
browning than green ones, showing severe discoloration even at 50°
if stored for more than about a month.
ORANGES
(Temperature, see text; relative humidity, 85 to 90 percent)
Although oranges are ordinarily stored at about 38° F., experi-
mental results have shown that for long storage (8 to 10 weeks) a
range of 34° to 38° gives better results. However, within this range
some decay, chiefly blue mold rot or green mold rot, may occur during
storage of 2 months or more, and some fruit may begin to show pit-
ting and brown stain of the rind. If stored for longer periods, decay
increases and the spotted fruit may gradually turn brown over all
or most of the surface. Watery break-down may develop, as in
grapefruit. Stem-end rot is likely to develop in Florida fruit if the
storage temperature is higher than about 34°. Among California
varieties, Washington Navel oranges are more subject to decay (blue
mold or green mold rots) than Valencia oranges. The Washington
Navel is also subject to alternaria rot.
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 25
Careful handling is necessary at all times to avoid injury to the
fruit. Decay, chiefly blue mold rot or green mold rot, frequently
follows injuries.
A free circulation of air around the boxes is desirable for oranges
as for other citrus fruit. A relative humidity of 85 to 90 percent is
sufficient to hold the shriveling of packed oranges to a minimum and
retards decay more than does a higher humidity.
Oranges should not be stored with eggs or butter, or in places where
it is possible for the orange odor to penetrate into egg- or butter-storage
rooms. (See also p. 14.) It is desirable that oranges in storage be
examined regularly and often to avoid loss from the development of
pitting or decay. After such examinations, a decision as to how long
the fruit can safely be left in storage should take account of the fact
that if pitting and decay are found they may increase rapidly after
the fruit is removed to higher temperatures.
(See 72, 92, 93, 94, 111, 113.)
PEACHES
(Temperature, 31° to 32° F.; relative humidity, 80 to 85 percent)
Peaches are not adapted to cold storage. However, if they are
sound and well-matured but not overripe, they can be held at 31° to
32° F. for 2 to 4 weeks, depending on the variety, with lttle or no
bad effect on the flavor, texture, or appearance of the fruit. Storage
for longer periods is usually harmful to all of these characters.
The peaches lose their flavor and natural bright color, become dry
and mealy, or wet and mushy, and show marked browning of the
flesh, especially around the stone. The loss in flavor is more rapid
at 36° and 40° than at 32°, and break-down develops sooner at 36°
and 40° than at either lower or higher temperatures. The best stor-
age varieties and the periods they can ordinarily be held in storage
~ are Tuskena (Tuscan), 8 weeks; Early and Late Crawford, and
Salwey, 4 weeks; Elberta and J. H. Hale, 3 to 4 weeks. Belle, Cham-
pion, Hiley, and Carman are less desirable as storage varieties and
cannot be expected to hold up well, even under optimum conditions,
for more than 2 or 3 weeks.
(See 7, 29, 33, 37, 38.)
PEARS
(Temperature, 29° to 81° F.; relative humidity, 85 to 90 percent)
BARTLETT PEARS
The successful storage of Bartlett pears (43, 53, 54) depends not
only on the temperature and humidity in the storage room but also on
the condition of the fruit when stored. If the highest quality is to be
obtained, Bartlett pears for storage should not be removed from the
tree until the ground color begins to lighten and the lenticels have
corked over. If picked before reaching that stage, they have a marked
tendency to wilt, scald, and break down in storage. They also tend
to break down in storage if picked when too ripe. The most desirable
temperature for the storage of Bartlett pears is 29° to 31° F. The
relative humidity should range from 85 to 90 percent. The maximum
829965494
26 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
period for storage for canning and local fresh markets is about 90
days, and for storage at shipping point and at terminal markets, 45
to 60 days.
FALL AND WINTER PEARS
For fall and winter varieties of pears (43, 67, 68), such as Anjou,
Bosc, Clairgeau, Comice, Easter Beurré, Hardy, Seckel, and Winter
Nelis, the most desirable storage temperature is 29° to 31° F. A rela-
tive humidity of 85 to 90 percent is most commonly used. However, a
relative humidity of 90 to 95 percent is maintained in some pear stor-
age rooms in order to prevent shriveling. Such humidities are main-
tained in connection with air velocities of 100 to 200 feet per minute.
The length of time for which it is safe to store these pears depends
on the variety and when it is picked and also on whether the fruit
is Shipped directly to a consuming center and there stored or is stored
at the shipping point for a time and. later shipped to market. In-
formation on these points is given in table 6. In using the table it
should be remembered that wide differences in keeping quality are
often found in pears from various producing sections of the country.
If Bose, Flemish Beauty, and Comice pears are held in cold storage
beyond their season they do not ripen satisfactorily or they may not
ripen at all (27). For best ripening after storage these and most
other varieties of fall and winter pears should be held at a temperature
somewhere in the range from 65° to 70°, preferably about 65°.
Taste 6.—Length of time at 30° to 31° F. for safe storage of certain
varieties of pears at shipping point and after shipment to market
(68) 7
Length of
Storage treatment and variety storage End of storage period
period :
Stored immediately after harvest: Months
PRAT Gy ee outs eee St Reeth eee 2 to 3 | September to November.
@omice et RI eres dy 2to 3 | November to December.
I BY Ovo neg Medlin. Sucteranahen: Puen vans iis be arric pam el 3 to 3% Do.
Clairgeauis tise EO ce Ps ec ne 6 | February.
VARTA OE SU ea Set een oe eae negra 5 to 6 | March.
Winters Néehs2ae nies Ses eee 6 to 7 | March to May.
RaASbereBeCUTne 2s.) aeons Seen itor’, Do.
Stored after 12-day transit period
(precooled) :
TD OU hes See wee 4to5 | March.
LSTEEy ee yg ell I Maen SS agua a ea xtr 2to 3 | September to November.
Comic eal wir yg he LEST AAR, ae 2to 3 | November to December.
BOSC VUE Fe hey eb yt LPS a 2 to 3 Do.
Claing eat Feu wed, Proce Pe OVER Ay 3 to 6 | November to February.
WanitergNiehics es! tek vivs sph ole 2 6 to-7 | March to May.
The commonest and most serious decays of fall and winter pears in
storage are gray mold rot, caused by the fungus Botrytis, and blue
mold rot, caused by the fungus Penicillium. Gray mold rot is able to
spread from decaying to sound healthy fruit and for that reason is
frequently called nest rot. Losses from this rot can be reduced by
the use of paper wrappers impregnated with copper (74). In the
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 27
Pacific Northwest blue mold rot, in the form known as pinhole rot,
is sometimes more important on pears, particularly Winter Nelis,
than gray mold rot. Losses from blue mold can be greatly reduced
by careful picking and handling, prompt storage at 29° to 31° F. after
harvest, and the use of paper wrappers to prevent direct contact.
between: diseased and sound fruit.
Kieffer pears, if they are sound, firm, and still green when stored
and are held under the conditions recommended for other fall and
winter pears, can be expected to keep satisfactorily for 2 or 3 months.
If intended for storage, they and other varieties should be handled
with extreme care during the picking and packing process, because
even slightly bruised or rubbed places are very likely to turn black
and seriously damage the sales value of the fruit. Investigations
(50) by the United States Department of Agriculture have proved
that a ripening temperature of 60° to 65° F. is essential for the at-
tainment of maximum quality in Kieffer pears for either dessert ‘or
canning purposes.
PINEAPPLES
(Temperature: mature green, 50° to 60° F.; ripe, 40° to 45°. Relative humidity,
85 to 90 percent)
Pineapples are not adapted to long storage. Fully ripe fruits can
be held satisfactorily at 40° to 45° F. for 2 to 4 weeks. Mature green
fruits should not be held at temperatures below 50° and even at this
temperature some of them will retain part of the green color in the
skin and will fail to develop good flavor in the flesh after removal
to room temperature. The maximum storage period for such fruit
at 50° is 3 to 4 weeks. When held at 60°, mature green fruit ripens
slowly, but after 2 or 3 weeks losses from decay, chiefly black rot, may
be expected. The relative humidity for pineapples in storage should
range from about 85 to 90 percent. —
(See 102, 110.)
PLums (INcLuDING PRUNES)
(Temperature, 31° to 32° F.; relative humidity, 80 to 85 percent)
Plums and prunes (fresh) are not stored extensively and are not
adapted to long cold storage. Such varieties as Wild Goose and those
of the damson type store better than the softer fleshed plums, such
as Santa Rosa, Beauty, Wickson, and Duarte. The storage period, at
31° to 32° F., ranges from 3 to 8 weeks depending on the variety.
After that time the soft-fleshed varieties are likely to become too soft
for commercial handling, may suffer some darkening of the flesh, and
lose somewhat in flavor. :
One of the most important commercial shipping and storage varie-
ties is the Italian Prune. Ata temperature of 32° F., 2 weeks is about
the maximum cold-storage period for this fruit if a shipping period
is necessary before it goes on the market. After arrival at market
prunes shipped immediately after harvest can ordinarily be held in
cold storage for about 3 weeks. If held longer there is danger that
shriveling, mealiness, and internal browning, as well as abnormal
flavor, will develop. Too much confidence should not be placed in
the appearance and condition of the fruit while it is in storage, as
more deterioration—decay, shriveling, and internal browning—may
28 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
take place in 3 days after removal from storage than during the whole
storage period. Fresh prunes shipped out of storage at shipping
point cannot safely be stored again after arrival at eastern markets.
Storage disorders can be prevented by partly ripening the fruit prior
to storage at 31° to 32° or by holding it at 40° to 45°.
(See 7, 26, 97.)
QUINCES
(Temperature, 31° to 82° F.; relative humidity, 80 to 85 percent)
The behavior of quinces in storage is about the same as that of early
varieties of apples such as Jonathan and Grimes Golden.
RASPBERRIES
(Temperature, 31° to 82° F.; relative humidity 80 to 85 percent)
Fresh raspberries, blackberries, Logan blackberries, and dewberries
are not adapted to storage and are usually not stored commercially.
For short periods, 7 to 10 days, most of them can be kept in fair condi-
tion by storage at 31° to 32° F. in a relative humidity of about 80 to
85 percent. Young and Boysen dewberries cannot be stored satis-
factorily for more than 8 to 4 days.
STRAWBERRIES
(Temperature, 31° to 382° F.; relative humidity, 80 to 85 percent)
Fresh strawberries are not stored commercially except for very
short periods; 10 days is probably the maximum. Even for so short
a time as this the temperature must be kept below 40° F. to prevent
loss from decay caused by certain low-temperature fungi such as
gray mold and Phytophthora, the fungus which causes leather rot;
31° to 82° is still better. After about 10 days, sometimes sooner, the
fruit loses its fresh bright color, shrivels more or less, and deterio-
rates in flavor (774). |
Driep FrutIts
(Temperature and relative humidity, see text)
For the preservation of natural color in storage, cut dried fruits
and dried berries that are not subject to sugaring are held at 26° F.
with no humidity control or at 32° with a relative humidity of 70
to 75 percent.
Figs and prunes are best stored at 40° to 45° F. The relative hu-
midity should not be over 70 to 75 percent, to prevent excessive absorp-
tion of moisture. Dried apples, apricots, and peaches keep best at
26° to 32°. Raisins should be stored at 40° to 45° and require a rela-
tive humidity of 50 to 60 percent to keep them from absorbing
moisture. The holding of dried fruit in high humidity at tempera-
tures above 32° is likely to result in mold. The dried fruits men-
tioned can be kept in marketable condition for 9 to 12 months at the
temperatures and humidities specified.
Dried fruit can be tightly stacked, without stripping, in large sohd
blocks in storage rooms without injurious effect, and this method of
handling the packages minimizes the absorption of moisture from the
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 29
storage-room air. When nonventilated packages, such as those used
for dried fruit and dates, are removed from cold rooms, the sweating
that results occurs mostly on the outside of the package and the
moisture can be prevented from penetrating into the fruit by allowing
the packages to warm up before they are opened (6).
FROZEN FRUITS AND VEGETABLES
(Temperature, see text)
Frozen fruits should be held at —10° to 0° F. if they are to be stored
for several months. |
For the freezing of fruits a temperature of 0° F. or lower is de-
sirable for both small containers and barrels. If freezing takes place
too slowly the same undesirable conditions may develop that are en-
countered if the fruit is stored at too high a temperature after being
frozen (17, 18, 96). .
For best results frozen fruits should be held in airtight containers.
The best temperature for freezing vegetables is from —10° to —5° F,
For storage after freezing —10° to 0° is satisfactory if ample pro-
vision is made for rapid cooling until the product reaches the
freezing point.
Nuts
(Temperature, 32° to 45° F.; relative humidity, 65 to 75 percent)
Most of the commercial nut crop, including walnuts of all kinds,
filberts, almonds, Brazil nuts, peanuts, and sometimes pecans, is usu-
ally held in ordinary warehouse storage through the winter follow-
ing harvest. The portion of the crop (except pecans) that is to be
kept through the following summer should be placed in cold storage
early in March. Pecans become stale and rancid much sooner than
most other kinds of nuts, and it is safer to put them in cold storage at
32° I. shortly after harvest. Brazil nuts can usually be kept satis-
factorily in warehouse storage during the winter, but that portion to
be held over summer should be stored at 32° before warm weather.
Brazil nuts should be carefully inspected before being accepted for
storage to see that they are well dried out, or cured. Walnuts, filberts,
and almonds usually need not be stored below 40° to 45°. Chestnuts
are rarely held in any other way than in cold storage at 32° to 40°.
Shelled and unshelled peanuts can be held at common warehouse
temperature during the winter, but during spring and summer shelled
peanuts should be kept in cold storage both for protection against
sects and to prevent development of rancidity. If cold storage is
not available, common storage can be used, but the peanuts should be
stored in the shell and shelled out as needed, because if stored shelled
they are likely to darken and become rancid. In common storage care
should be taken to prevent infestation by insects. Fumigation is de-
sirable for both shelled and unshelled peanuts if they are to be held
in common storage during the summer for any considerable time.
As all varieties of nuts keep better unshelled than shelled, it is
usually the best practice to store nuts in the shell and crack them as
needed unless the kernels can be sealed in vacuum, which will permit
them to be kept even longer than in the shell. Generally nut kernels
should be stored at 32° F.
30
CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
The relative humidity of the storage room should be 65 to 75 per-
cent.
lower humidities there will be undue drying.
(See 1/7.)
VEGETABLES
By R. C. WRIGHT, physiologist
The recommended temperature, relative humidity, and approximate
length of storage period for the commercial storage of vegetables
are given in table 7. Detailed descriptions of these requirements are
given in the text.
At higher humidities there is danger of mold growth, and at
TasiE 7.—Recommended temperature, relative humidity, and approxi-
mate length of storage period for the commercial storage of various
vegetables, and the average freezing points
Commodity
ASPAT AGUS Oia ems
Beans:
Green orisnapi2s 2) 8
Lima:
Unshelleds2u2 2. ius
Broccoli (Italian, or sprout-
ing).
Brussels’sproutse) f2 rec)
Cabbage
Celeriac
Celene = A ed ama a
Corn (ereem) mS em
Cucumbers@ is) 12 ORS
Bgeplamtisies ) aye sia ee
EINGhiiy ee Se er URS ees
Garlic (dry)
Horseradish
TEC TEUCES SF ee nak et tee he
Muskmelon (cantaloup) -
Honey Dew and Honey
Ball.
CO) ethene lin wi PR tan GE ES aE
ture
A oi
32
32 to 40
32
32 to 35
32 to 35
32
36 to 40
32 to 34
36 to 38
36 to 40
32 tO oo
50
See footnotes at end of table, p. 31.
Tempera-| Relative
humidity
Approximate
length
of storage period
Average
freezing
point !
Percent
85 to 90
85 to 90
85 to 90
85 to 90
85 to 90
85 to 90
95 to 98
85 to 90
90 to 95
90 to 95
90 to 95
95 to 98
85 to 90
85 to 90
95 to 98
90 to 95
85 to 90
85 to 95
85 to 90
90 to 95
70 to 75
95 to 98
90 to 95
95 to 98
85 to 90
90 to 95
75 to 85
75 to 78
75 to 85
75 to 85
80 to 85
85 to 95
1 to 3 months
10 to 14 days. _+___-
CAO iircenge Bk se
3 LO 4nWwEeeKSE OU WR cpa
3 to 4 months
10 to 14 days_______
2 sto 3oweeksels Sis
3 to 4 months
2 to 4 months
10 to 14 days______-
LOndhaiyige! cary 25.05 pee Bye
DitOye WeCKS Ee Sass
6 to 8 months
10 to 12 mont
2 to 5 months
Agte)
2 to 4;rweeksis_ 2s
1 to 3 months
2 GO OEWee KS = ae ee
(aLOnlOKday c= eae
2*to 4 weeks= S50
A to Gsweeks4 2) 222 eee ee
2 to 3 days__
Diweekgeis \ oan aaees
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 31
Taste 7.—Recommended temperature, relative humidity, and approxi-
mate length of storage period for the commercial storage of various
vegetables, and the average freezing points—Continued
; : Average
5 Tempera-| Relative | Approximate length :
Commodity. ture humidity of storage period ee
point
Celie Percent oe aA
Onionceeyh. fer en SZ COMCOnLom OO tOre montis.) = a2 5 30. 1
Onion sets! =e so ese Si neh OMCOnGa| 2 === GOn et ree as 29. 5
1 EAH STON OFS gy ak Ea S237 90) to, 97 2.to 4: months. 22 = 28. 9
Peasr(ereem)e — 7.25 23. cs 38214| 85) to 90) a to 2 weeks____- = 30. 0
Peppers:
Chili Gres yeaa se sk (2) MOMCOniS al OrtorOumontbhs: 2) aya) a eT
Syweebe Sefer ane 32 | 85 to 90 | 4 to 6 weeks_______- 30. 1
Potatoes:
Byam yes, Ses eS yey ps Aesth (?) Sou Os9O el) sede ey Sees ee Ue En cas Sag
LE ShaRde Seat ep Seah get fy Les SSELOLO OMe SoOMbOnO OAs (2) iis a ths Melee A. nla s 28. 9
Pumpkins 2 23 S24 ta ts ro 50 to 55 | 70 to 75 | 2 to 6 months______-_ 30. 1
Radishes (winter)__.____-- 32 1595 tor 98\ |. Zato;4 months. 28 2) | eee
ilanulloaing oe oe a Fg oe 32 | 90 to 95 | 2 to 8 weeks________ 28. 4
ubaloa gases se ae te ey 32 | 95 to 98 | 2 to 4 months- __--__-. 29. 5
Nalsifys GES EEO SE BLE 9S). TOn9 Sw. 2 GOR Sasha Ae 28. 4
Dpolmach< wy aye pers we gs 32 | 90 to 95 | 10 to 14 days___-___-_ 30. 3
Squashes:
ROLUL OGIO 0) pa sane Senet rem Ay DIRE nm 40 to 50 | 85 to-95 | 2°to 3 weeks_.-.-_--|s_-__=_
VWatterie aero, 50 to 55 | 70 to 75 | 4 to 6 months______~_ 29. 3
DVRCCEDOLAUOCS aa ae es 2'50' to: 50) ,| -SOkto 85 4/2 Uae Goya MU Sas = He 28..5
Tomatoes:
Ripe sapere wc tbe AN 10150) 1380 to 850) 71to 10 daysusso222 30. 4
Matumeroreen s\2 22a 2 255 to 70 | 80 to 85-| 3 to 5 weeks____-__z 30. 4
AUT NI SP pearsall < beew ty 32 | 95 to 98 | 4. to 5 months... ___= 30. 5
1 These figures are based on previously published work by Wright (1 16) and
are subject to revision whenever further investigation makes this necessary.
2 See text. 3 Flesh. 4 Rind.
ASPARAGUS
(Temperature, 32° F.; relative humidity, 85 to 90 percent)
Fresh asparagus is not usually stored except temporarily when the
market is overstocked. Experiments have shown, however, that it can
be kept successfully for 3 to 4 weeks at a temperature of 32° F. At this
temperature, growth of the stalks, which takes place at higher tem-
peratures, is practically nil. The original tenderness of fresh aspara-
gus, which at ordinary room temperatures is lost soon after cutting
owing to the formation of woody tissue, is preserved at the lower tem-
perature. Furthermore, the sugar content, to which asparagus owes
some of its flavor and which after cutting rapidly diminishes at higher
temperatures, remains practically the same as when the asparagus
is cut, if it is put in storage at this temperature immediately after
cutting. Therefore, the sooner asparagus is placed in proper storage
after harvesting the better will be its condition when used. The loss
of water while in storage or transit is likely to be great if the stalks
are not stood on wet moss or other moist absorbent material placed in
the bottoms of the crates. In storage, asparagus bunches are some-
times set in water in shallow trays or pans. After a long haul to
market, asparagus should not be expected to keep in storage for more
than 3 to 6 days, although the preservation of quality will depend
32 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
largely on how the product was handled before being received for
storage. Asparagus that has been precooled immediately after being
packed will arrive at the market in better condition than if not so
treated. The principal decays of asparagus in storage are bacterial |
soft rot and gray mold rot.
(See 69.)
BEANS
(Temperature, 32° to 40° F.; relative humidity, 85 to 90 percent)
GREEN, OR SNAP
Green beans are usually stored for only short periods. When
held at 32° F. they may be expected to keep 2 to 4 weeks provided they
are in good condition and are placed in storage promptly. At 40°
the storage period will be about a week shorter. The humidity should
not be lower than 85 percent, to prevent wilting, and the hampers or
other containers should be so stacked as to allow abundant air circu-
lation. If the containers are packed close together the temperature
may rise somewhat because of the heat given off by the commodity, »
and more or less rapid decay may be expected. If the beans are stored
too long, the pods may become moldy or slimy and stick or “nest”
together. The principal kinds of decay favored by too high storage
temperature or too long holding period are watery soft rot, slimy
soft rot, rhizopus rot, and gray mold rot.
LIMA
Shelled lima beans are sometimes stored in quart baskets and, if
fresh and sound when stored, can be expected to keep in good salable
condition for about 15 days at 32° F. and about 4 days at 40°. If
stored too long, the beans tend to fade to a light color and become
sticky. Unshelled lima beans can be held satisfactorily for 2 to 4
weeks at 32° and 10 days at 40°.
BEETS
(Temperature, 32° F. Relative humidity: topped, 95 to 98 percent; bunch,
85 to 90 percent )
Late beets stored at 32° F. may be expected to keep 1 to 3 months
under suitable storage conditions. Either cold storage or cool cellar
storage is suitable provided the humidity is kept sufficiently high to
prevent wilting. Cellar storages often have a higher average tem-
perature range than is recommended, and under these conditions the
period of successful storage will be comparatively shorter. ‘The tem-
perature in such storage should not go above 45°. Beets are subject
to wilting because of the rapid loss of water and should be kept where
the humidity is sufficiently high to prevent excessive evaporation.
Before going into storage, beets should be topped and well sorted
to remove all diseased specimens and those showing mechanical injury,
in order to prevent undue shrinkage because of storage decay. Beets
may be stored in ventilated barrels or better in slat crates. Storage
in large bulk should be avoided.
Bunch beets may be stored at 32° F. for 10 days to 2 weeks. See dis-
cussion of bunch carrots (p. 34), as the same conditions apply as for
bunch beets.
STORAGE ‘OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 33
Broccoit (ITALIAN, OR SPROUTING)
(Temperature, 32° to 35° F.; relative humidity, 90 to 95 percent)
Italian, or sprouting, broccoli does not keep well in storage and is
usually held for only very short periods. The best storage tempera-
ture is 32° F.. If in good condition and stored with sufficient ventila-
tion between the packages, broccoli should keep satisfactorily for a
week or 10 days. Longer:storage is undesirable because the leaves
are likely to discolor and the buds may drop off (76).
BrussELs SPROUTS
(Temperature, 32° to 35° F.; relative humidity, 90 to 95 percent)
Brussels sprouts are stored only occasionally but when stored they
require the same conditions as broccoli. They should be held in
small containers to prevent yellowing and the development of mold.
The maximum storage period is probably not longer than 3 to 4
weeks,
CABBAGE
(Temperature, 32° F.; relative humidity, 90 to 95 percent)
A large percentage of the late crop of cabbage is stored and sold
during the winter and early spring, or until the new crop from the
Southern States appears on the market. If stored under proper con-
ditions, cabbage should keep for 3 to 4 months. The longest keeping
varieties belong to the Danish Ballhead class. Cabbage is most suc-
cessfully held in common storage in the Northern States, where a fairly
uniform inside temperature from 32° to 35° F. can be maintained.
Many such storage houses are to be found, principally in New York,
Pennsylvania, Michigan, and Wisconsin. Cabbage in quantity
usually is not held in cold storage because its value does not justify
the expense of handling.
Storehouses should be insulated sufficiently to prevent freezing, for
although shght freezing does no harm, hard freezing is likely to
cause considerable loss. More ventilating capacity than is required
for most other vegetables should be provided to carry away the ex-
cessive moisture given off by the active respiration of this product
and to obtain the maximum advantage of the cold night air during
mild weather. Cabbage wilts quickly if held under too dry storage
conditions; hence the humidity should be high enough to keep the
leaves fresh and turgid. Bin storage is common, the bins usually be-
ing 4 to 5 feet wide and 10 to even 20 feet long and about 5 feet deep.
They are best separated by tight board partitions and ventilating
slat floors. Tiers of bins may be built.as high as it is convenient to
elevate the cabbage, and while the bins are being filled ample air space
between the tiers of bins should be allowed for ventilation. The
use of slat shelves with the heads piled one or two layers deep is con-
sidered the best method, but it is too expensive when large quantities
are to be stored.
Cabbage should be handled carefully from the field to the storage.
Before it is stored, the roots and all loose leaves should be trimmed
away and the damaged and misshapen heads should be culled. On
82996549 5
34 CIRCULAR 278, U. S.. DEPARTMENT OF AGRICULTURE
being removed from storage, the heads should be trimmed again to
remove loose and damaged leaves.
Early cabbage, especially southern-grown, should not be expected to
keep over 3 to 6 weeks even at 32° F. —
The most common decay found in stored cabbage is slimy soft rot.
CARROTS
(Temperature, 32° F. Relative humidity: topped, 95 to 98 percent; bunch,
85 to 90 percent)
Carrots are stored in fairly large quantities during the winter.
The marketing period for stored carrots extends to late winter or
early spring. They are usually held in common storage in those sec-
tions where the storage temperature can ordinarily be held sufficiently
low. In the larger markets stored carrots must be sold in competition
with fresh stock, which is being shipped practically the year around
from either southern or western producing sections. Carrots are
sometimes held in cold storage, although the prices obtained for them
do not usually justify this kind of treatment.
It is generally considered that very light freezing causes practically
no injury, but carrots should be protected from severe freezing and
are best stored at a temperature of 32° F. They are subject to wilting
or drying out if the humidity is not fairly high; for this reason they
are more easily kept in a well-ventilated cellar or bank storage than in
an above-ground storage. The relative humidity should be main-
tained at 95 percent or slightly higher.
Before being placed in storage, carrots should be topped and all
misshapen orinjured specimens sorted out. The latter are especially
objectionable, because their presence in a storage lot favors the devel-
opment of two serious diseases of stored carrots, namely, watery soft
rot and bacterial soft rot.. Carrots are best kept in slat crates or ven-
tilated barrels, and provision should be made for air circulation be-
tween the containers. Under good conditions they should keep 4
to 5 months. |
Bunch carrots may be stored at 32° F. for 10 days to 2 weeks, and
the tops will still retain a fresh appearance if they are not crowded
in storage. If cold storage is not available bunch carrots from dis-
tant production sections may be packed in crushed ice and should keep
at least a week. If it is desired to carry over such carrots for only
a day or two, icing may not be necessary. Under these conditions,
however, the crates or containers should be opened and the contents
loosened so as to allow air to circulate through; otherwise, heating
will take place, and the foliage will soon become yellow or discolored ;
this, of course, 1s undesirable.
Foliage will discolor sooner if kept warm and wet than if kept
cool and dry.
CAULIFLOWER
(Temperature, 32° F.; relative humidity, 85 to 90 percent)
Cauliflower is not usually kept in cold storage; however, an over-
supply on the market can be stored for a short time to await more
favorable conditions. If in good condition cauliflower can frequently
be held satisfactorily for 2 to 3 weeks at 82° F. Successful storage
depends not only on preventing decay but also on retarding the ma-
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 30
turing of the head, or curd. Overmaturity is marked by a browning
of the otherwise white curd and the development of a ricey appear-
ance. ‘The leaves also become yellowish and may drop off. During
storage or transportation the crates should be stacked with the flower
heads down to protect the curds from discoloration by dirt and mois-
ture. When it is desirable to hold cauliflower temporarily out of cold
storage, packing it in crushed ice will aid in keeping it fresh. Freez-
ing causes a grayish-brown discoloration and softening of the curd,
accompanied by a water-soaked condition.
CELERIAC
(Temperature, 32° F.; relative humidity, 95 to 98 percent)
Celeriac should be stored under the same conditions as those for
topped carrots and should keep 3 to 4 months.
CELERY
(Temperature, 31° to 32° F.; relative humidity, 90 to 95 percent)
Much of the late celery grown in the Northern States, notably New
York and Michigan, is put in cold storage to supply the market up
to the period in late winter when the competition of new celery from
California and the South renders further holding unprofitable. Con-
siderable celery from the South and West is also put in cold storage
toward the end of the shipping season and field to supply the market
during the summer, or until supplies of early, northern-grown stock
appear on the market.
Celery is a rather perishable commodity and under unsuitable
storage conditions may suffer severely from watery soft rot. This dis-
ease originates in the field and is caused by a fungus that is able to
develop to some extent even at temperatures of 34° to 36° F. For
this reason celery intended for storage should be as free as possible
from infection. If held in rooms where a uniformly low temperature
can be maintained, it should keep for 2 to 4 months. It is best stored
at a temperature of 31° or 82° with a relative humidity high enough
to prevent wilting (90 to 95 percent), and with sufficient air circulation
to keep the temperatures at the top and bottom of the room as nearly
equal as possible. Considerable heat is given off by celery because of
active respiration, and the air at the top of a storage room is likely
to be 8° to 4° warmer than at the bottom unless special precautions are
taken to avoid such a condition. Air circulation can be maintained
around the crates by using 1- by 2- or 2- by 2-inch dunnage strips
between the crates, which should be stacked so as not to touch at the
sides. If wall or ceiling refrigerating coils are used, fans should be
located at such positions as will insure adequate air circulation. If
the storage period is long, celery will keep better in small crates than
inlarge ones. |
Celery should not be piled more than four crates high in storage;
otherwise there is danger of overheating even with stock that is in
prime condition. If it is piled five to eight crates high, as is sometimes
done, the room should be watched carefully to see that overheating
does not occur.
36 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
Some growth takes place in celery while in storage. The central
stalks lengthen considerably, obtaining their food at the expense of
the outer stalks and the roots. Blanching of the stalks also takes
place in most varieties that are put into storage. Some celery is
trimmed and washed as it comes from storage, but probably the
larger part is moved out in the original crates in which it was
received.
(See 95.) *
Corn (GREEN)
(Temperature, 31° to 32° F.; relative humidity, 85 to 90 percent)
Green corn is seldom stored, although there are occasions during
the southern shipping season when it may be desirable to put an excess
supply of this commodity temporarily in cold storage; however,
storage for more than a few days will result in serious deterioration.
The sugar content, which so largely determines quality in this product
and which rapidly decreases at ordinary temperatures, is reduced
very little if the corn is quickly cooled and kept at a relatively low
temperature. In order to keep this loss of sugar to a minimum and
preserve the flavor, corn in the husks as it comes from the field for
consumption in the fresh state should be cooled as quickly as possible.
This is sometimes done by submerging it in tanks of ice water immedi-
ately after removal from the field to reduce the temperature to as near
32° EF. as possible.
Corn should not be handled in bulk because of its tendency to heat
but should be put in baskets or crates, which allow air circulation and
the more rapid removal of field heat and heat produced by respira-
tion. This commodity as it usually arrives on the market should not
be expected to keep in marketable condition in cold storage for more
than 4 to 8 days.
CUCUMBERS
(Temperature, 45° to 50° F.; relative humidity, 85 to 95 percent)
Cucumbers are usually held in storage for only short periods and
cannot be expected to keep satisfactorily for much over 10 to 14 days.
The most favorable storage temperature range seems to be between
45° and 50° F., with a relative humidity of 85 to 95 percent. When
cucumbers are held at 45° or below for longer periods than recom-
mended dark-colored watery ateas, which are an indication of low-
temperature injury, appear. ‘These areas soon become infected, and
mold growth develops. If the cucumbers are held at 50° little or no
break-down develops, but they tend to ripen, the color changing from
green to yellow, and there may be some shriveling and surface pitting. *
Waxing is practiced commercially, usually with a paraffin-carnauba
emulsion ‘containing approximately 7 percent solids. This treatment
reduces weight loss ‘and improves appearance.
* THOMPSON, H. C. CELERY STORAGE. | Refrig. Res. Found.] TRRF Fact File
Sheet. 2 pp. October 1947. [Processed.]
* Morris, L. L., and MANN, L. K. STORAGE OF CUCUMBERS. Refrig. Res. Found.
Fact File Sheet. 1p. December 1948. [Processed.]
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 37
EGGPLANTS
(Temperature, 45° to 50° F.; relative humidity, 85 to 90 percent)
Eggplants cannot be expected to keep satisfactorily in storage for
more than about 10 days.
ENDIVE, OR ESCAROLE
(Temperature, 32° F.; relative humidity, 90 to 95 perecent)
Endive, or escarole, is a leafy vegetable and under commercial con-
ditions is not adapted to long storage. Even at 32° F., which is con-
sidered to be the best storage temperature, it cannot be expected to
keep satisfactorily for more than 2 or 3 weeks. The storage require-
ments for endive are practically the same as for lettuce. Like lettuce
it should keep somewhat longer than the period just mentioned if it
is stored with cracked ice in or around the packages. ‘The relative
humidity in rooms where endive is held should be kept at 90 to 95
percent in order to prevent wilting.
A certain amount of desirable blanching usually occurs in endive
that is held in storage.
Garuic (Dry)
(Temperature, 32° F.; relative humidity, 70 to 75 percent)
Garlic is best stored under the temperature and humidity condi-
tions required for onions. If in good condition and well-cured when
stored, this product should keep at 32° F. for 6 to 8 months. In
Cahfornia, where considerable garlic is grown, it is frequently put
in common storage, where it may be held for 3 to 4 months or some-
times longer if the building can be kept cool, dry, and well-ventilated.
Garlic is stored in loose mesh bags, which are piled two layers deep in
stacks separated by air spaces. It is essential that garlic be well
cured in the field before going into storage.
HorsERADISH
(Temperature, 32° F.; relative humidity, 95 to 98 percent)
Horseradish should keep satisfactorily for 10 to 12 months if stored
under the conditions recommended for topped carrots.
JERUSALEM-ARTICHOKES
(Temperature, 31° to 32° F.; relative humidity, 90 to 95 percent)
Jerusalem-artichokes, if held in storage at a temperature of 31° to
32° F. in a relative humidity of 90 to 95 percent, may be expected
to remain in good condition 2 to 5 months. At low humidities they
shrivel badly and are more likely to decay than if kept in a moist
atmosphere. They are sometimes stored in barrels or in paper-lined
bags, in which they keep longer, with less wilting and decay, than if
left in open containérs.
38 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
KoHLRABI
(Temperature, 32° F.; relative humidity. 95 to 98 percent)
Kohlrabi should keep 2 to 4 weeks if stored under the conditions
recommended for topped carrots.
LEEKs (GREEN)
(Temperature, 32° F.; relative humidity, 85 to 90 percent)
Green leeks are crated and stored under conditions similar to those
suitable for celery. If properly handled, they should keep satis-
factorily for 1 to 8 months in storage.
LETTUCE
(Temperature, 32° F.; relative humidity. 90 to 95 percent)
Lettuce is sometimes put in cold storage when there is a surplus
on the market, or in certain sections when the fall crop is threatened
by approaching cold weather. If in good condition when stored, it
can be expected to keep for 2 or 3 weeks. When lettuce is held tem-
porarily out of cold storage crushed ice will greatly aid in keeping it —
fresh. Even when it is held in cold storage, ice tends to keep this prod-
uct fresher by preventing drying or wilting.
One of the most troublesome diseases of lettuce in transit and stor-
age is tipburn of the type that develops in the interior of the head.
This injury appears in the field, but in the later stages of the market-
ing process it is frequently followed by a slimy bacterial decay, which
may result in serious damage. Frequent inspection of stored lots is
desirable.
MELONS
Cold storage is used very little for most kinds of melons. When it is
used, the storing is generally done at the terminal markets to avoid
temporary adverse market conditions.
WATERMELONS
(Temperature, 36° to 40° F.; relative humidity, 75 to 85 percent)
The ordinary commercial varieties of watermelons cannot usually be
expected to keep in storage for more than 2 or 3 weeks. Experimental
lots have been held at temperatures of 32° F. and did not develop
decay as rapidly as at the recommended temperatures, but there was a
tendency for the melons to become pitted or dented and to take on an
objectionable flavor after 1 week.
MUSKMELONS (CANTALOUPS)
(Temperature, 32° to 34° F.; relative humidity, 75 to 78 percent)
The common commercial varieties of cantaloups can be expected to
keep about 1 week in cold storage at the recommended temperatures
after arrival on the market and, under favorable conditions, for a
few days longer but not as long as 2 weeks. The riper the melons are
on arrival, the shorter the storage period should be. When they are
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 39
held too long in storage, decay develops so rapidly on removal that
they soon become practically worthless.
(See 70.)
HONEY DEW AND HONEY BALL MELONS
(Temperature, 86° to 38° F.; relative humidity, 75 to 85 percent)
Honey Dew and Honey Ball melons can usually be kept a little
longer in storage than cantaloups. At 36° to 38° F. or slightly lower,
such melons can be expected to keep for 2 to 4 weeks and still reach
the consumer in good condition. If held for a longer time at tem-
peratures below 36°, low-temperature break-down marked by a watery
discoloration of the rind, followed by fungus decay, will probably
result ; at 36° to 88°, decay, which will seriously discolor the rind, may
occur. All blemishes show more plainly on these melons because of
their light-colored, smooth surfaces.
CASABA AND PERSIAN MELONS
(Temperature, 36° to 40° F.; relative humidity, 75 to 85 percent)
Casaba and Persian melons are relatively good keepers. They will
remain in good condition in storage for at least 4 weeks and have been
reported to keep as long as 6 weeks.
MusHrooms (CULTIVATED)
(Temperature, 32° to 385° F.; relative humidity, 80 to 85 percent)
Mushrooms do not keep well in storage and are therefore stored
only temporarily for periods of 2 to 8 days or slightly longer. ‘They
are easily injured by freezing.
OKRA
(Temperature, 50° F.; relative humidity, 85 to 95 percent)
Okra, if in good condition, can be kept satisfactorily in storage for
a maximum of 2 weeks at a temperature of 50° F. A relative humidity
of 85 to 95 percent is desirable to prevent wilting. At temperatures
below 50° okra is subject to chilling injury, which is manifested by
surface discoloration, pitting, and decay. °
ONIONS AND ONION SETS
(Temperature, 32° F.; relative humidity, 70 to 75 percent)
Onions are held in either common or cold storage. In the northern
onion-growing States, strongly flavored varieties, mostly of the globe
type, are generally held in common or dry storage. ‘The principal
northern onion-producing States have a sufficiently low average winter
temperature so that onions can be successfully held in common storage
there during the winter months. About one-fourth of the onion crop
of these States, however, is put in cold storage for consumption late
in the spring. About the first of March is considered as late as onions
should be held in common storage, because after this time there is
danger of sprouting. The mild, or Bermuda, types, such as those pro-
*Morris, L. L., and Mann, L. K. STORAGE OF OKRA. Refrig. Res. Found.
Fact File Sheet. 1p. December 1948. [Processed.]
40 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
duced in Washington, southern California, Texas, and other States
where the climate is not suitable for common stor age, are usually con-
sumed shortly after being harvested. These onions can be, and limited
quantities are, held in cold storage, but usually for much shorter
periods than the globe varieties because of their peorer keeping
qualities. The Spanish, or Valencia, type of onions grown in this
country are often stored and, if well- matur ed, are considered capable
of storage for practically as long as the globe type.
A comparatively low relative. humidity (70 to 75 percent) is very
desirable for the successful storage of onions. At higher humidities,
in which many other vegetables keep best in storage, onions are dis-
posed to root growth and decay. The commonest form of the latter
is gray mold rot occurring at the top of the bulb, whence its name
“neck rot” (98). The fungus causing it can develop to some extent
even at 32° F.; hence onions intended for storage should be carefully
sorted over to remove all diseased bulbs. A uniform temperature of
32° is found to be sufficiently low to keep onions dormant and reason-
ably free from decay provided they are in good sound condition and
well-cured when stored.
Onions are not perceptibly injured by shght freezing if allowed to
thaw out slowly and without rough handling. In cold storage they
are usually held in bags of 50 or 100 pounds each, which are best piled
in pairs laid crosswise in stacks five or six sacks high. The stacks
should be set a few inches off the floor on 2- by 4- inch strips and the
individual stacks separated by a few inches of space to allow for air
circulation. When kept in common storage, onions are best stored
in slat field crates holding about 1 bushel, rather than in bags. Be-
fore being placed in storage onions should be well dried or cured in
the field for a period of 4 to 6 weeks, and all decayed specimens or
those showing thick, or “bottle,” necks should be sorted out.
Onion sets are usually held in common storage. They require
nearly the same conditions as large onions and are best stored in
shallow slat-bottom crates or trays not over 4 inches deep and about
5 by 5 feet in some districts or 2 by 3 feet in others. The corner posts
of the crates should project about an inch above the side pieces in
order to prevent the crates from resting tightly on each other when
stacked and to allow air circulation between them. Because of their
size, onion sets tend to pack closely in the crates; hence it is essential
to allow as much air circulation as possible and to maintain a com-
paratively low humidity. If good stock is provided and is held under
proper storage conditions, it should keep 6 to 8 months.
(See 57.)
PAaRSNIPS
(Temperature, 32° F.; relative humidity, 90 to 95 percent)
Parsnips have nearly the same storage requirements as topped car-
rots and should keep for 2 to 4months. They are not injured by shght
freezing while in storage but should be protected from hard freezing
aud should be very carefully handled while in a frozen condition.
Parsnips dry out readily in storage; hence it is essential that the
humidity of the storage place be kept relatively high. Parsnips are
sometimes stored in sand or clean soil to prevent wilting, but they
will keep in good condition when held in barrels or crates if the
proper humidity is maintained.
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 41
Pras (GREEN)
(Temperature, 32° F.; relative humidity, 85 to 90 percent)
Storage conditions required for green peas are somewhat different
from those for beans. Green peas tend to lose part of their sugar con-
tent, on which much of their flavor depends, unless they are promptly
cooled to near 32° F. shortly after being picked. They cannot be
expected to keep in salable condition for more than 1 to 2 weeks unless
packed in crushed ice, in which condition the storage period may be
extended perhaps a week. Peas keep better unshelled than shelled.
. PEPPERS
CHILI PEPPERS (DRY)
(Temperature, see text; relative humidity, 70 to 75 percent)
Chili peppers are usually picked when ripe and then dried and
allowed to equalize in moisture content in covered piles. Water is
usually added to the peppers after drying, and as a result they become
less brittle. They are then packed tightly by tamping into sacks
holding 200 to 800 pounds and stored in nonrefrigerated warehouses
for 6 to 9 months. |
The temperature of the warehouses depends to some extent on their
censtruction and the way in which they are managed but chiefly on
the outside temperature. In southern California, where a large part
of the commercial crop of Chili peppers is produced, the outside
temperature ranges from 50° to 80° F. during the usual storage
period.
The moisture content of Chil peppers when stored is generally low
enough (10 to 15 percent) to prevent mold growth; the chief storage
trouble is insect infestation. Sometimes manufacturers of Chili pep-
per products hold part of their supply of the raw material in cold
storage, but they prefer to grind the peppers as soon as possible and
store them in the manufactured form in airtight containers.
SWEET PEPPERS
(Temperature, 32° F.; relative humidity, 85 to 90 percent)
Sweet, bell, or bullnose peppers, if in good condition may readily
be kept fresh in storage for a month to 6 weeks at a temperature of
32° F. A relative humidity of 85 to 90 percent is desirable to prevent
shrinkage (46).
POTATOES
EARLY CROP
(Temperature, see text; relative humidity, 85 to 90 percent)
Early and intermediate potatoes are not often stored. However,
if need arises in the production area (usually southern) this crop
can be kept satisfactorily in common unrefrigerated storage through
the summer in the locality where it is grown (44). The potatoes
should, of course, be sorted over carefully before storage to remove all
42 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
those decayed and seriously bruised and cracked. Investigations in
Oklahoma (75) indicated that refrigerated storage at 50° F. after a
curing period is best: for the early crop. Some evidence has been
obtained, however, that, if early potatoes are to be used for chipping
purposes, a storage temperature of 60° to 70° is better than one of 50°.
The relative humidity should be the same as that for the late crop.
If refrigeration is not available, an underground storage cellar or
cave is next best if the temperature can be held below 70° and a fairly
moist atmosphere maintained to avoid excessive shrinkage. (See also
49.)
It almost goes without saying that under the conditions suggested
the storage period would never be so long as is possible with late-crop
potatoes.
LATE CROP
(Temperature, 38° to 50° F.; relative humidity, 85 to 90 percent)
Potatoes are stored either in cold or common storage, but the greater
part of the crop that is stored is held in common storage (20). Like
most other vegetables that can be held for relatively long periods in
common storage, potatoes can be successfully kept through the fall
and winter months only in those sections where a sufficiently cold
winter climate prevails. In either cold or common storage a temper-
ature of 40° F’. is as low as table or seed stock need be kept during the
first few months after harvest. At temperatures below this, there is
a tendency for potatoes to become undesirably sweet. However, if
sweetening occurs, a few days’ exposure to ordinary living-room tem-
perature will partly restore the natural flavor. Potatoes should always
be kept in the dark to prevent greening. At 40° potatoes will remain
dormant 5 to 8 months after harvest, depending on the variety. If it
is desired to keep them longer than this, as is often the case with seed
stock, the temperature may be lowered to 38°, at which they should
remain dormant indefinitely. A storage temperature as low as 32° is
not only unnecessary but detrimental. |
Investigations have indicated that potatoes stored at 50° to 60° F,
have better texture, color, and flavor when cooked or made into chips
than the same stock stored at lower temperatures (64, 120), although
the higher temperatures are not suitable for long-time storage. When
potatoes are stored at these higher temperatures, sprouting will occur
more quickly. A limited amount of sprouting does not injure potatoes
tor food purposes, but it makes the stock difficult to market because
usually only dormant potatoes are wanted. If sprouting has started it
can be checked by lowering the storage temperature.
Potatoes that have been kept at 40° F. for a long time are seldom
suitable for processing, such as chip making, french frying, or dehy-
drating, without first being conditioned to reduce the quantity of sugar
that has accumulated. This is accomplished by holding the potatoes at
70° to 80° until trial cooking tests show that they have recovered sufh-
ciently for use. The length of the conditioning period will depend on
the variety and the amount of sugar that has accumulated; usually,
however, this will be 1 to 3 weeks (123).
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 43
The relative humidity of a potato-storage house should be 85 to 90
percent, to prevent undue shrinkage through loss of water. In cold
storage, potatoes are generally kept in sacks holding 50 or 100
pounds net ; in common storage they are usually placed in bins holding
from 150 to as much as 1,000 bushels or more. In Maine and northern
New York, where the average temperature is sufficiently low, the
large-bin storage is used with success, but in the milder climate of
States in the latitude of Pennsylvania potatoes should not be stored
in such large units. Potatoes are readily injured by even slight freez-
ing, which takes place at about 29° F. or slightly below ; hence common-
storage buildings should be sufficiently insulated to prevent freezing.
Insulation will also prevent the condensation of moisture on the walls
and ceilings and the consequent undesirable wetting of stored stock,
which favors the development of decay. Common storages should be
provided with sufficient ventilation to take advantage of the cool night
air in mild weather; this will aid in removing excess moisture,
accumulating especially soon after potatoes are stored in the fall,
and will maintain a lower average temperature. Ventilators should
never be opened, however, when the outside temperature is higher
than that inside the storage house. In addition to damage to potatoes,
condensed moisture caused by improper ventilation or inadequate
insulation may also cause serious impairment to the building struc-
ture (19).
Potatoes intended for storage should be handled carefully to avoid
bruises and cuts; otherwise they are lhkely to be damaged by various
forms of decay before the end of the storage period.
PUMPKINS AND SQUASHES
(Pumpkins and winter squashes: temperature, 50° to 55° F.; relative humidity,
70 to 75 percent. Summer squashes: temperature, 40° to 50°; relative
humidity, 85 to 95 percent )
In general most varieties of pumpkins will not keep in storage as
long as the usual storage varieties of squash. Such varieties as Con-
necticut Field and Cushaw are relatively poor keepers and cannot be
expected to hold in good condition more than 2 to 3 months. Varieties
like Large Cheese and Table Queen will keep 3 to 6 months.
Hard-shell squashes, such as the Hubbards, can be successfully stored
for 6 months or longer.
All stock should be well-matured, carefully handled, and free from
Injury or decay when put in storage. The best storage temperature
appears to be 50° to 55° F. with a relatively low humidity of about
70 to 75 percent. Investigations have shown that a preliminary -
curing at 80° to 85° for about 2 weeks is of benefit in ripening immature
specimens and in healing mechanical injuries incident to harvesting.
Summer (yellow crookneck) squashes keep best at a temperature of
about 40° to 50° F. and a relative humidity of 85 to 95 percent. Under
these conditions, they may show some increase in the yellow color,
pitting, and some wilting at the necks after approximately 3 weeks;
but they are not likely to be seriously damaged by decay.’
“Morris, L. L., and MANN, L. K. STORAGE OF SUMMER SQUASH. Refrig. Res.
Found. Fact File Sheet. 1p. December 1948. [Processed. ]
44 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
RapisHES (WINTER)
(Temperature, 32° F.; relative humidity, 95 to 98 percent)
Winter radishes require the same storage conditions as topped
carrots and should keep in good condition for 2 to 4 months.
RHUBARB
(Temperature, 32° F.; relative humidity, 90 to 95 percent)
Rhubarb stalks, if fresh and in good condition, may be stored for
2 to 3 weeks. The bunches should be packed in crates, which are
stacked to allow ample air circulation on all sides; otherwise there
is danger of heating and mold growth.
RUTABAGAS
(Temperature, 32° F.; relative humidity, 95 to 98 percent)
Rutabagas require the same storage conditions as topped carrots
and should keep satisfactorily under such conditions for 2 to 4 months.
Probably most of the rutabagas that now appear on the market have
been waxed. This treatment improves the appearance and is reported
to prevent wilting and loss of weight.
SALSIFY
(Temperature, 32° F.; relative humidity, 95 to 98 percent)
Salsify has the same storage requirements as topped carrots. The
roots are not injured by slight freezing but should be carefully
handled while frozen. Under the conditions specified, they should
keep for 2 to 4 months.
SPINACH
(Temperature, 32° F.; relative humidity, 90 to 95 percent)
Spinach is usually stored for only short periods. It should keep
fairly well for a week or two after being cut. If crushed ice is used
in the packages, this period can be extended somewhat.
SQUASHES
See Pumpkins and Squashes.
SWEETPOTATOES
(Temperature, 50° to 55° F.; relative humidity, 80 to 85 percent)
The requirements for the successful storage of sweetpotatoes differ
from those recommended for most other vegetable crops. When
freshly dug sweetpotatoes are to be stored for any length of time they
should be given a preliminary curing treatment to permit the healing
of all wounds or abrasions incident to harvesting and handling, in
order to prevent the entrance of decay organisms.
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 45
The curing and storing are done in the same house so that the
potatoes do not have to be moved after the curing treatment. When
commercial lots are handled, the storage house is generally of special
construction with sufficient insulation to maintain a uniform tem-
perature and some means of ventilation that will insure the desired
humidity. Provision should be made for heating the building during
the curing process and for holding the proper storage temperature
afterward. The curing process ordinarily takes about 10 days, during
which the house is kept at a temperature of 85° F’., with a relative
humidity of 85 percent. After the curing period the storage tem-
perature is allowed to drop to about 55°, with a humidity of 80 to
85 percent. Short periods of a few hours at temperatures somewhat
lower than 50° need not cause alarm, but prolonged periods of low
temperature should be avoided because of the danger from certain
types of decay, which are more likely to develop at temperatures below
the range given (45,61). Under the recommended conditions, prop-
erly cured stock should keep satisfactorily for 4 to 6 months.
Only well-matured stock that is practically free from mechanical
injury or decay should be used for storage. Sweetpotatoes are usu-
ally stored in slat crates of about a bushel capacity or in bushel baskets.
Shallow bins are sometimes used. The roots should be handled as
little as possible during storage. :
(See 40.)
TOMATOES
(Temperature: ripe, 40° to 50° F.; mature green, 55° to 70°. Relative humidity,
80 to 85 percent)
Ripe tomatoes are held in storage only temporarily and, except for
short storage, should not be stored at temperatures lower than 40° F.
At 40° to 50°, if not already soft ripe, they will keep in good condition
for a week to 10 days; at temperatures lower than this they sometimes
show a tendency to break down.
Green tomatoes are best kept at a temperature not lower than 55° F.
At this temperature ripening progresses slowly but satisfactorily, and
mature green tomatoes can be kept for 3 to 5 weeks before becoming
overripe. At temperatures much below 55° green tomatoes do not
ripen well and if kept there more than about 8 days and then moved
to a warmer place usually do not ripen satisfactorily; on the other
hand, if they are to be kept for less than 8 days they can be held at
40° or even somewhat lower. If fairly rapid ripening is desired,
temperatures from 60° to 70° should be used. At 70° or slightly above,
ripening is accelerated, but so also is the development of decay, which
will be found difficult to control. At about 80° coloring will be un-
even since the development of the red pigment is inhibited at this
temperature or above. The relative humidity of tomato-storage or
tomato-ripening rooms should be from 80 to 85 percent.
(See 101, 119, 121.)
TURNIPS
(Temperature, 32° F.; relative humidity, 95 to 98 percent)
Turnips require the same storage conditions as topped carrots.
They can be expected to keep for 4 to 5 months.
46 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
FROZEN VEGETABLES
For treatment of frozen vegetables see page 29.
CUT FLOWERS, FLORISTS’ GREENS, RHIZOMES, TUBERS, »
CORMS, AND BULBS
By T. M. WHITEMAN, associate horticulturist
The recommended temperature, relative humidity, and approximate
length of storage period for the commercial storage of cut flowers,
florists’ greens, rhizomes, tubers, corms, and bulbs are given in ta-
ble 8. Detailed descriptions of these requirements are given in the
text.
TaBiE 8.—Recommended temperature, relative humidity, and approxi-
mate length of storage period for cut flowers, florists’ greens,
rhizomes, tubers, corms, and bulbs
Commodity nae! Approximate length
ine of storage period
Cut flowers: ! an Oe
Babysbréathisee tlt eee er a ee ee 40 | 3 to 4 days
Bouvardiaesweete22: fas 5 222. er eee 40 | 7 to 10 days
Butterflybush, orange-eye______-___-------- 40 | 3 to 4 days
Calendulat(potsmanicold) Sa. sean 40 | 3 to 6 days
Callavcommon-and golden - oo _ 49348 Serer 40 | 10 days.
Candytuits 22226 oe ae 2. ee an eee 40 | 3 to 6 days
Carnation:
Rulitbloomsar 24 eee tea ici eer 33-40 | 7 to 10 days.
BGS 5 Ee sia ss Ded Ea ep ea a yg 33-40 | 10 to 15 days
Ching-asten 5 e266. oe eee ape ee ge 40 | 7 to 10 days
Chrysanthemums a eee eee 35 | 2 weeks.
Clarkia 4 itiect te Pais TOV ee Se 40 | 3 to 6 days
Columbine =e * eee ee ee 40 | 3 to 4 days
Wornilowermties. 20) 6. = ae ae ee 40 | 3 to 6 days
CrOCUSH ars Soe eee atte ge ee Be ee 33-36 | 1 to 2 weeks
1 E50 FE vest ih as pr ps A eh Si lagi ts Soya Bc Ne A 40 | 7 to 10 days
Daisy; Pnglishi0 SBAse_ Gyo TOT aaaR: © 40 | 3 to 6 days
Delphinium:
Hardyalsrikcs piece te oe Gea eee ee aie 40 Do.
Annuallarks pure eo feces pee 40 |-3 to 4 days
WE VETIC Wire See Loe eRe ene ae Se eee ae 40 | 3 to 6 days
Horget=me-not; trues2_2 235. & fi ant eee 40 | 3 to 4 days
Foxglove, common and common white- - - --- 40 Do.
TeGSIAUE: 2 O82). ee eke eee ee 33-36 | 1 to 2 weeks
Gaillardia, common perennial -_--_---------- 40 | 3 to 6 days.
Gardeniaes 20 4 ee ee ae 45-50 | 1 week.
Gladiolus erat Un nae fe ee 35 | 2 weeks.
He@athe “bal elie 3) teen eee ne ee eee 40 | 7 to 10 days
Fy acing i ges ey SS oe Poe oe ee oe 33-36 | 1 to 2 weeks
Tris Cte hes = Soe Se ee eee ee 33 | 1 week.
Laceflower, blue! 222220 sO 22) Ue Beane eee 40 | 3 to 6 days.
Lily:
HaStere oF ee Sees A coe ea ine ere 35 | 1 month
Gold ban deen 2 es See oo ea 35 Do.
Realy Hatin Ok ee eT RAC 35 Do.
Speciostim:. 0p hs ea ire hh eee ee See 35 Do.
Lily-of-the-valleys_22 5122 See See 40 | 1 week.
Tiypine 26! oS ink ee es Ee ee ee 40 | 3 to 6 days.
See footnotes at end of table, p. 47.
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 47
TasiE 8.—Recommended temperature, relative humidity, and approwi-
mate length of storage period for cut flowers, florists’ greens,
rhizomes, tubers, corms, and bulbs—Continued
Tem- :
3 Approximate length
Commodity Fie of storage period
ure
Cut flowers: !—Continued
Narcissus: Stk
1D) aio Wears oe eS ree pees aioe Serre 33-36 | 1 to 2 weeks.
Ra perwiiter aes eee ts woe the ets 33-36 Do.
Ohi eats Se eee ce ae 45-50 | 1 week.
Peony, Chinese and common:
Mroatm oS! oe ae a cere a Re oo 35 | 3 to 4 weeks.
MooscsOMd se sears, see e) bie ep 35 | 10 to 14 days.
iBhloxarardenes 2A" e sere e see ee cme 40 | 3 to 4 days.
TPL TOSIS mb se on Se ae fi pe ae ep ae 50 Do.
GI FOSE Gas ee eee ee ee eS ee 40 Do.
EROS Cee eles Peo Re ek oye re 35-40 | 1 week.
Snapdraconscommoneen s'est ee eee = 40 | 3 to 6 days.
Snowaropiie cise ae see ee hee nee a Eee 33-36 | 1 to 2 weeks.
STU Ls pa eae alt ee lel ng Sie 33-36 Do.
SeaticenGeaslavenGen) at a. spe oe oer 35-40 | 3 to 6 weeks
SUE hao) ors ag Ses SS teen gi Dali Ne ieD ies R EAR ae 40 | 3 to 4 days
SLOCescOmMm one atta ee bet Ee 40 | 3 to 6 days
trawl wie steer ei Teeter ween CL EE ier 35-40 | 3 to 6 weeks.
DSN CX EUBI]OL OLE IRE ot SR yo Slag ae a a eee 40 | 3 to 4 days
Rt eee ee See ee ee ye ee 33-36 | 1 to 2 weeks
WiGlet sweeter: seme oe eee Skee 33-36 | 3 to 6 days
Florists’ greens:! .
ASparacus ern anGysnoilax © osc ee vite oo! 40-45 | 7 to 10 days.
Ferns:
Commonrwoodfernes 2) as Se a ee 32-45 | 2 weeks to 4 months.
Dale cereal ash) Te Cee AA ee ee oe 32-45 O.
Crea xe hs ae rin a banger ener ete a) 32-45 Do.
Croundpine (uycopodium)ia 4 = 32-45 Do.
FLOW WACHL EL ODGCG) a oes ees 32 | 1 month
PUGS oer ye ees eee es ER Ne SR ee 32-40 | 3 to 6 weeks.
Eevuecthoesdroopingwim A wtl iene. pani 32-40 Do.
Mountain-laurel tat 88 26 salve oper expec 32-40 Do.
Rhizomes, tubers, corms, and bulbs: ?
Bevonidecuoena s.r er em ea sak ate 45 | 4 to 6 months.
Caladiuinr spotted es wks Pies AN eed 45 Do.
Calla, \common and golden=_/___=- 22-22 35 | 6 to 8 months.
Canna srs. sxe sha A area ae eel a 40-45 | 6 to 7 months.
Cr OCU Se ene erat ao ye Sa AE ee epee 55-60 | 4 to 6 months.
ID FEN UL chy las eet eat att opera Marsares hat 40-45 | 6 to 7 months.
ee siat yas Ce? ke IPE SER ko) SPUD REEL 55-60 | 4 to 6 months.
GladioluswA2e _ ashy. lew robes sy ek | Fy os 40-50 | 7 to 8 months.
1B Lyf: 176)'b 29 0 a ea ene BORD Ie oe Avnet SOR ee nen 55-60 | 4 to 6 months.
ily:
ASU CTY Cancer tare eee ee gre aie ers eee 32-35 | 6 to 8 months.
Regal sc: SOR Gaal tie). “RE SE a OE 32-35 Do.
inily-of-the=valleyee) ae ty fe hey sete 25-28 | 12 to 17 months.
Narcissus:
IDE 06 (6 bl hey pl enero nh one orga Sneath a a aE a 55-60 | 4 to 6 months.
IR ApeLWteka seem en ere eT nee S42 75-80 | 5 to 7 months.
Orn ER CD ST LE TA TRC aS UNE 40-45 | 6 to 7 months.
SNOWOTOp sats rere oe 8 A jel i pe Lest ye) 55-60 | 4 to 6 months.
SK (SUD gee Sea aa ae Sa eae Meee ar oe ea ee 55-60 Do.
UST aa es a nae em 45 Do.
UCT OSC me eee ARISTA TRIAL ANI BAD PD. 40-45 | 6 to 8 months.
Mp ase Fo ts were be ita 2 wd 110d 5 50-55 | 4 to 6 months.
1 Approximately 80 percent relative humidity.
2 Approximately 75 percent relative humidity; for individual species see text.
4S CIRCULAR 278, U. 8. DEPARTMENT OF AGRICULTURE
The average freezing points of some flower petals, foliage, bulbs,
corms, etc., are given in the following tabulation:
RBPIOWO NOOCDNOCMORUUMNTIONNWO ww
Foliage: Temperature (°F.)! | Petals—Continued Temperature (° F.)
Amarylliss 2.2 See ee 31.0 Daisy;.Shastas+-2-s = eee 29.
Asparagusslernis ta nem e 24. 2 Delphinium (hardy lark-
ANSDICISCrAa” 2 os 22 Seen 24. 9 SIU) es Sly ye a ae 26.
Caladium, spotted__...=-__ 30. 6 Gardenmianes.- "0-5 yee aes 28.
Carnation: 24 2a 27. 4 Gladiohistes. <n eee 28
Chrysanthemum = ees 29. 6 Heather ees. ee 28
Columbines a= Sa een 29. 1 Hemerocalliste:: ~ = = sueuee 30
Daisy; Shasta-s 3s eee = 30. 0 Fiyvacintheeeeeres .> Tree 28.
Delphinium (hardy lark- irise Japaneseses.. 22 a0 ee 30.
ON 5) ngs ee Pa i te CE age 9. 2 ihilyacbastert.. soe as 2
Dracaena: ==) ears © ee 28. 0 Narcissus (daffodil) __-______ 30.
Ferm’) dagger 2. Bi. yaa 23. 6 Orchid (Catileya) = a2 30.
Gag oOhUses sac aetence ates 26. 8 Peony, commons. sass. == 29.
Hiemerocallishs2 22) = = 30. 0 Poimsettiaece ss). ae 29.
Holly Gilexiopaca) ta 26. 3 Ranunculuss2222 2) Soe 28.
Tris: Rose; hy bridttea > asses ee 30.
Datel ares sates 29. 0 qCultp = = 26 =. ae 28.
Germann. as tee ee 27. 6 Violét, Sweet. 2. ae ae 28.
Japanese. 22 Pie ce 28. 7) Bulbs, corms, ete.:
lhily..astere!-=— 3 S24 eee 29. 2 Calltea se ae a ee 27
PanG@anus= se hae tee ee 30. 4 Dahliaa. = Sees 28
Rubber, variegated________ 30. 3 Gladiolus2222 34 = 2 Uren 26
Violet sweets2= 4-2 pe. 22 = 27. 4 Eliy S.C lint nee ee ee 28
VAN CQ anajOne = eee Ree 28. 6 Dnily, Revalss2sSsss = 2am 20.
Petals: Narcissus:
IATICIMIONG se eee oe 28. 1 Daliodils toss 26. 1
Carnation. Sse t seen 28. 4 Paperwhites.——2 =e 28.9
Chrysamthentume = — 28. 4 Dulas Fe. Pea ee eer ee 25. 4
Columbinese= 2 == =5 eae Slew
1 Many of these figures are based on previously published work by Wright (116) and are subject to revision
whenever further investigation makes this necessary.
Cut FLoweErs
The best prestorage handling of cut flowers not only includes the
selection of species and varieties known to be good keepers but also
provides for the use of well-grown blooms only. Well-grown flowers
are those that have developed under near-optimum water, nutrient,
temperature, and hght conditions and that have received no mechani-
cal or other damage while on the plant. Flowers of such quality are
“firm” and are said to have “substance,” terms which probably could
be justified on the basis of total solid matter, as contrasted with soft
blooms that usually develop under conditions of forced growth. Well-
grown flowers do not have hard, or excessively woody, stems for the
species; hard stems make water uptake difficult.
In preparing cut flowers for storage the proper cutting stage, dis-
cussed under individual species, is of prime importance. Most cut
flowers are benefited by a freshening period of a few hours (in water)
at about 50° F. immediately after being cut, unless intended for dry
storage. Bunching is usually done before storage. Flowers should
be bunched and tied firmly but not too tightly or in too large bunches.
Wrapping the bunches with waxed paper with an opening at the top
prevents tangling of the blooms during the handling of such species
as delphinium, columbine, and lilies-of-the-valley; of course, in the
case of roses wrapping of the bunches is customary. If intended for
storage in water, cut flowers should be stored at the proper tempera-
ture soon after they have been freshened at 50°.
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 49
One of the chief factors influencing the storage life of cut flowers
istemperature. There is no known treatment that is nearly so satisfac-
tory in extending the life of cut flowers as is storage at comparatively
low temperatures. If the proper temperature is used, inherent quality
should not deteriorate appreciably during a short storage period. The
temperatures given here are recommended to insure a reasonably long
life for flowers after their removal from storage. Cut flowers for
which 45° to 50° F. is recommended, when stored at a much lower
temperature, may not keep well after removal from storage. ‘Those
for which a storage temperature of 33° is recommended will naturally
mature more rapidly if stored at any higher temperature. If held at
33° they develop slowly. Often the changes in storage are not ap-
parent, but the longer the blooms are stored at 33° the shorter will be
their life when later they are used for decorations. On the other
hand, if short-lived blooms that keep best when held at 40° are stored
at 33° they show the effect of the previous adverse conditions after
they are placed at ordinary room temperature (70°-75°).
In case a variety of flowers needs to be stored and only one storage
room is available it is suggested that a temperature of 40° be used:
The length of time that the blooms are to be stored should always be
considered. For a number of items table 8 shows the recommended
storage temperature as well as the range in the approximate length
of the storage period.
The effect of humidity on the storage of cut flowers deserves more
consideration than it has had in the past. A relative humidity of
90 to 95 percent is probably too high in that 1t may promote mold
growth, especially if the blooms are somewhat crowded. At low
relative humidity, 70 to 75 percent, the petals of certain types of
flowers may tend to dry to an undesirable degree. A relative humidity
of 80 percent is therefore recommended. It has been noted with cer-
tain types of blooms, such as gladiolus, that floret development was
faster in a room with a temperature of 36° F. and a high relative
humidity than in a room at the same temperature and a lower
humidity.
In constructing a storage room for cut flowers one of the most im-
portant considerations is air circulation. To get good air circulation
the vases or buckets of flowers should be set on racks arranged so
that air can pass through and back of them. Forced but gentle air
movement should be provided, but the blooms should not be in a direct
draft. The containers should be spaced so that the blooms are not
crowded.
Cut flowers in storage should usually be kept with the stems in
water. They should not be crowded in the container because of the
danger of mechanical injury and the decay that may result because
of insufficient ventilation. In most cases care should be taken not
to spill water on the blooms as these usually discolor rather readily.
Experiments in which French marigolds and carnations were stored
out of water for comparatively long periods have been reported
(60,61). Peonies are known to keep fairly satisfactorily when stored
out of water.
Damage to several kinds of cut flowers when stored in the same
room or even in the same building with apples, oranges, pears, and
other fruits should be emphasized. Such damage is evidenced by.
premature withering or the rapid aging of the blooms and is thought
50 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
to be caused by the ethylene gas given off by the ripening fruit. Roses,
carnations, snapdragons, stocks, and daffodils have been shown to
be affected in this way by the emanations from ripening fruit (47,
68). Since ethylene gas is used at times to defoliate rose bushes and
is known to cause premature dropping of foliage from cut sprays ot
holly, it may also affect such greens as mountain-laurel and huckle-
berry. Greens therefore should not be stored near the fruits
mentioned.
Many kinds of pigmented flowers fade, discolor, or develop an off-
color appearance during storage, especially under dark storage con-
ditions. The effectiveness of artificial light in retarding this color
change has been demonstrated experimentally (59).
Chrysanthemums (Chrysanthemum hortorwm) and giladioluses
(Gladiolus) may be stored at 35° F. for 2 weeks and usually remain
very salable. Longer storage is possible, though frequently not prac-
ticable. These flowers are usually tied in bunches of 12 and 25, respec-
tively, but are not wrapped when placed in storage. Pompons,
however, are sold in bunches of various sizes.
As a rule the proper cutting stage for the large-flowering types
of chrysanthemums is just after the green color in the center of the
flower has disappeared. No general rule can be given for pompons,
since several varieties, especially some of those in the anemone group,
need more development on the plant than the single varieties.
Gladioluses should be cut when three or four of the lower buds are
partly opened. However, for distant shipments before storage one
or two of the lowest florets should show color but should be in the
tight-bud stage. Gladiolus spikes should always be shipped and
stored in a vertical position (105). |
Easter lily (Lilium longiflorum), Speciosum lily (L. speciosum),
Regal lily (LZ. regale), goldband lily (ZL. awratum), common peony
-(Paeonia officinalis), and Chinese peony (P albiflora) can be held
at 35° F. for comparatively long periods, although 30 days is usually
the maximum storage period. ‘The lies in this group should be cut
for storage when the corolla is about one-half opened or just before
the tips begin to reflex. Liles forced at relatively high temperatures
should be kept at a temperature of about 50° for a preliminary period
of about 24 hours before being put at 35°. Peonies showing color in
the tight-bud stage may be stored at 35° for 3 to 4 weeks, but they
seldom give satisfaction for decorative purposes without special han-
dling; in the loose-bud stage they may be held satisfactorily for 10
to 14 days.
The cut blooms of common and golden callas (Zantedeschia aethi-
opica and Z. elliottiana) may be stored when fresh for as long as 10
days at 40° F. and will be in good condition upon removal. Calla
blooms should be gathered just before the spathe shows signs of
curling downward. Callas that have been subjected to hard forcing
should be held for about 24 hours at a temperature of 50° previous
to storage at 40°. When the blooms are gathered they should be
pulled, not cut, otherwise the stems will split at the cut ends and curl
after a few days in storage. The pulling method separates the stem
from the rhizome, leaving no useless appendage. Although the
blooms are sometimes removed from the plant by cutting, the stub
left on the plant will probably rot and thus may serve as a place of
entrance for disease organisms. Pulling, however, is much easier
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 51
with potted callas than with those planted in beds or benches. Callas
intended for storage should be tied near the end of the stem and also
loosely tied below the blooms. They are usually put up in lots of
1 dozen.
Lupine (Lupinus), clarkia (Clarkia), common stocks (Matthiola
incana), candytuft (lberis), delphinium, or hardy or perennial
larkspur (Delphiniwm formosum and hybrids), cornflower (Cen-
taurea cyanus), feverfew (Chrysanthemum parthenium), common
snapdragon (Antirrhinwm majus), blue laceflower (TZ rachymene
caerulea), English daisy (Bellis perennis), calendula, or pot marigold,
(Calendula officinalis), and common perennial gaillardia (Gaillardia
aristata) should not be held at temperatures lower than 40° F., and
cannot be stored with good results for more than a 3- to 6-day period.
Sweet violets are usually made up in bunches of 100, supported under-
neath by a few galax leaves and wrapped with a light waxed paper,
and should be stored at 33° to 36°.
Columbine (Aguilegia), stevia (Piqueria trinervia), babysbreath
(Gypsophila paniculata), annual larkspur, baby primrose (Primula
jorbesiz), sweet pea (Lathyrus odoratus), true forget-me-not (Myo-
sotis scorpioides), and orange-eye butterflybush (Buddleia davidii)
all have flowers whose petals shed quickly, almost regardless of tem-
perature. They cannot be held much lower than 40° F. or for longer
than 3 to 4 days without impairing the keeping quality after removal.
Forced Buddleia is sold by the dozen. ‘The others mentioned are
bunched in lots of 25. It is not customary to wrap any of these for
storage, but, as previously mentioned, certain kinds may be wrapped
to prevent tangling with adjacent bunches.
Orchids and gardenias (Gardenia augusta, G veitchi, and G. for-
tunez) are not customarily stored for long periods. However, they
may be kept in storage in good condition for about a week at a tem-
perature of 45° to 50° F. They keep best when cut just after they have
reached a salable condition.
Carnations (Dianthus caryophyllus) cut in full bloom may be held
at 33° to 40° F. for 7 to 10 days. If cut in the bud stage they may
be stored at 33° to 40° for 10 to 15 days. Several varieties of carna-
tions, although it is not known how many, will develop satisfactorily
when cut in the bud stage, viz, when one or two petals have unfolded
from the bud, and will last considerably longer than if cut at a more
advanced stage of maturity (47).
‘Roses for nearby markets should be cut in the loose-bud stage; if
they are to be shipped to distant markets they should be cut in as
tight a condition as is permissible with the variety in question. In
the loose-bud stage they may be held at 35° to 40° F. for 1 week; if
stored at lower temperatures the subsequent keeping quality is often
impaired (59). These are often tied loosely in bunches of 25 buds
and wrapped with parchment paper.
Dahlias (Dahlia), China-asters (Callistephus chinensis), sweet
bouvardia (Bowvardia humboltiz), and heath (Frica) may be held 7 to
10 days at 40° F. They usually are handled in lots of 1 dozen, tied, but
not wrapped.
Statice, including bigleaf and notchleaf sea-lavender (Limoniwm
latifolium and L. sinwatum, respectively), and strawflower (Helich-
rysum bracteatum) may be kept at 35° to 40° F. for 3 to 6 weeks.
They may be dried and will retain their original color and shape;
52 CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
strawflowers are usually dried instead of being stored to retain their
freshness.
Common foxglove (Digitalis purpurea), common white foxglove
(D. purpurea var. alba), and garden phlox (Phlox paniculata) are
not ae satisfactory for storage but may be held for 8 or 4 days at
40° F.
The various forced irises, especially the so-called Dutch irises, may
be held for 1 week at 33° F. (106).
Cut poinsettias (Z’uphorbia pulcherrima) sold during the Christmas
season usually need not be stored for the few days between their
arrival at the wholesale house and the day of sale. If holding is neces-
sary, storage at about 50° F. is recommended. Any change of en-
vironment, such as improper storage, will increase the apparently
inherent tendency of poinsettias to shed their foliage. They should
be cut when showing sufficient color to be salable. Searing the cut
ends with boiling water is a practice usually followed to prevent undue
loss of sap before or during storage.
Cut lilies-of-the-valley (Convallaria majalis) are kept satisfac-
torily at 40° F. and may be held for 1 week at this temperature; if
they are kept longer the lower bells often become watery in appearance
(104). The proper cutting stage is just after the terminal bell has
lost its deep-green color. It should be of a yellow-green appearance,
the lower 3 or 4 bells at this time being well opened. They are usually
tied with foliage in bunches of 25 and are better wrapped loosely in
heavy waxed paper, leaving the tops and bottoms of the bunches open.
Hyacinth (Hyacinthus orientalis), tulip (107), narcissus (daffodil
and paperwhite), freesias (Freesia refracta var. alba), squills, snow-
drops (Galanthus nivalis), and crocuses can usually be held satisfac-
torily for 1 to 2 weeks at 33° to 36° F.
Spikes, such as snapdragons, should be cut just after the lower five or
six flowers have fully opened; umbels, such as blue lacefiower, should
be cut just after they develop to a salable condition; flowers formed in
heads usually should be cut after the outermost petals are fully de-
veloped and just before stamens appear in the center of typically
single heads or after the center has become closed with petals in
double sorts; corymbs, such as candytuft, are usually best when cut
after three-fourths of the lower flowers are opened; flowers described
as thyrses, or corymbose cymes, such as the hlac, should be cut when
about two-thirds of the determinate branches are developed; cymose
clusters, such as babysbreath, should be cut after a few of the terminal
flowers have developed.
Experiments have been reported on the use of a plastic coating on
gardenia blooms (87). With further tests on different types of
blooms, the usé of such materials may become more extensive as a
supplement for cold storage or during shipment.
FLorists’ GREENS
Fern asparagus (Asparagus plumosus) and smilax asparagus (A.
asparagoides) are usually shipped in crates. The turn-over of these
greens is rapid and shipments are arranged so that storage for longer
than 3 or 4 days is usually unnecessary, but they may be kept in the
case for 7 to 10 days at 40° to 45° F. The sprays of A. plumosus are
tied in bunches of various sizes. Smilax is packed in the crates in
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 53
various lengths or “strings.” The commercial popularity of A.
sprengeri has declined so much that it is produced and used chiefly by
small retail growers.
Drooping leucothoe (Leucothoe catesbaez), huckleberry, and moun-
tain-laurel (alma latifolia) sprays may be held in good condition at
32° to 40° F. for 3 to 6 weeks. ‘They are usually tied in bunches and
kept standing in water.
Galax (Galax aphylla), groundpine (Lycopodium), dagger ferns,
common woodferns, and various other species including Vryopteris
intermedia, packed in crates, may be held at 82° to 45° F’., depending
on the length of time it is desired to keep them. At 32° they may be
expected to keep 1 to 4 months, whereas at 45° they may be kept for
but 2 to 3 weeks in good condition. They are not put in water, but if
stored loose they are kept moist by occasional sprinklings. If they are
held in wooden cases or packed in such a way as to prevent excessive
drying out by direct air currents, no sprinkling is necessary. Galax
is usually tied in bunches of 25; the ferns are tied in lots of 50; but
both are customarily sold by the hundred. ‘Those who make a busi-
ness of gathering the greens in this group sometimes store them in
coldframes, covering them with about 6 inches of some material such
as sphagnum moss or leaves, and shading or using sash as the weather
demands. Handled in this way, shipments can be made at any time.
Others who might be termed “brokers” have many employees gather-
ing galax and ferns and store their entire holdings in cold-storage
warehouses; this is the method commonly employed for storage, and
it usually gives satisfaction.
Holly (lex opaca) sprays or wreaths can usually be held satisfac-
torily for approximately 1 month at a temperature of 32° F. and a
relative humidity of about 80 percent. ‘These should be left in the
packing cases to prevent the circulation of air immediately around
them (122).
A plastic coating has been used on such greens as fern asparagus,
dagger fern, and cut branches of several evergreen trees (35, 87). .
RHIZOMES, TUBERS, AND CorMsS
Lily-of-the-valley pips or crowns may be held in cold-storage ware-
houses at a temperature range of 25° to 28° F. (104) up to 17 months,
although after about 12 months increasing deterioration in quality
becomes noticeable. The pips are tied in bundles of 25 with string or
willow ties and are packed with sphagnum moss in wooden cases of
various sizes containing 250 to 2,500 pips.
Taro (Colocasia esculenta), spotted caladium (C. neoguineensis),
and tuber begonias (Begonia tuberhybrida) may be held at 45° F.
and a relative humidity of 75 to 80 percent for 4 to 6 months. They
should be packed in dry sawdust, sand, or peat.
Canna (Canna indica), dahlia (Dahlia) (3), and peony (Paeonia)
may be stored at 40° to 45° F. over a period of 6 to 7 months with a
relative humidity of 70 to 80 percent. They are usually packed in
dry soil, sand, sawdust, or peat moss.
Gladiolus (mostly hybrids) may be stored at 40° to 50° F. with a
relative humidity of 70 to 75 percent for 7 to 8 months. A tempera-
ture of 40° will hold these corms dormant during the normal storage
season, whereas at 50° sprouting will occur after 4 to 6 months’ stor-
54 CIKCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
age. ‘They should be stored dry in shallow trays with ample ventila-
tion but only after a curing period of 3 to 6 weeks in an open or well-
ventilated shed.
Common and golden callas (Zantedeschia aethiopica and Z. elli-
ottiana) stored at 35° F. and a relative humidity of 70 to 75 percent in
dry soil, sand, or peat will keep for many months if it is necessary to
store them. The normal rest period in the forcing cycle is during
May, June, and July. Unless water is withheld during this period
complete dormancy will not exist. Therefore, storage in a dry con-
dition is essential, with sufficient humidity to prevent undue shriveling.
BuLss
Most, varieties of daffodils (Narcissus), hyacinths, freesias, squills
(Scilla), snowdrops (Galanthus nivalis), Crocus, and similar bulbs
may be held at 55° to 60° F. for 4to 6 months. However, these as well
as tulips (Tudipa) are usually not stored, because better results are
obtained by planting them as soon as they are received. Paperwhite
narcissus (108) may be stored at 75° to 80° for 5 to 7 months from
digging time. |
Tulips are usually not stored in any packing material, although
the use of such material may be advantageous for long storage. Tem-
peratures of 36° to 38° F., except for short storage, are considered
rather low for tulips shipped from the West in which the buds are
already formed. The best storage temperature for shipped tulips is
between 50° and 55°, at which they may be kept for 4 to 6 months.
Tuberoses (Polianthes tuberosa) stored at a temperature of 40° to 45°
may be expected to keep satisfactorily for 6 to 8 months.
Bulbs of the genus Lilium, of which there are approximately 50
species, are like most other bulbs in giving best results if planted when
received. However, as Easter lihes are forced during the entire year,
it becomes necessary to provide cold-storage conditions suitable for
satisfactory holding until they are wanted for planting. The bulbs
should be packed in boxes in thoroughly dry soil if rooting and desic-
cation are to be prevented. A temperature of 32° to 35° F., with a
relative humidity of 75 to 80 percent, is recommended; under these
conditions they may be held for 6 to 8 months.
The procedure of storing certain bulbs for a time previous to plant-
ing at a temperature that will subsequently hasten flowering is in con-
sidetable use commercially. Bulbs so handled are said to be “pre-
cooled” (7, 31, 32).
LIPERATORE-€lieD
(1) ALLEN, FE. W.
1932. POSSIBILITIES AND LIMITATIONS OF COLD STORAGE FOR STONE FRUITS.
Ice and Refrig. 82: 424.
and PENTzER, W. T.
1936. STUDIES ON THE EFFECT OF HUMIDITY IN THE COLD STORAGE OF FRUITS.
Amer. Soc. Hort. Sci. Proc. (1935) 33: 215-228, illus.
(3) ALLEN, R. C.
1938. TEMPERATURE AND HUMIDITY REQUIREMENTS FOR THE STORAGE OF
DAHLIA RooTS. Amer. Soc. Hort. Sci. Proce. (1987) 35: 770-773.
(4) Bain, H. F., BERGMAN, H. F., and Witcox, R. B.
1942. HARVESTING AND HANDLING CULTIVATED CRANBERRIES. U. S. Dept.
Agr. Farmers’ Bul. 1882, 24 pp., illus.
(2)
(6)
(18)
(19)
(20)
(21)
(22)
(23)
(24)
(25)
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 955
BARGER, W. R.
1933. EXPERIMENTS WITH CALIFORNIA DATES IN STORAGE. Date Growers’
Inst. Rpt. 10: 3-5. ;
———— PENTzER, W. T., and FISHER, C. K.
1948. LOW TEMPERATURE STORAGE RETAINS QUALITY OF DRIED FRUIT. Food
Indus. 20: F1-F4 (20: [887]—[340] ), illus.
Biaauw, A. H., VERSLUYS, M. C., LUYTEN, I., and others.
1925-26. THE RESULTS OF THE TEMPERATURE TREATMENT IN SUMMER FOR
DARWIN TULIPS. K. Akad. van Wetensch. te Amsterdam, Afd.
Natuurk. Proe., Sect. Sci. 28: 717-731, illus., 1925; 29: [113]-
126, [199]-220, illus., 1926.
Brooks, C., Coontry, J. S., and FisHemr, D. F.
1930. DISEASES OF APPLES IN STORAGE. U.S. Dept. Agr. Farmers’ Bul.
1160, 20 pp., illus. (Revised.)
and HARLEY, C. P.
1934. SOFT SCALD AND SOGGY BREAK-DOWN OF APPLES. Jour. Agr. Res. 49:
55-69, illus.
and McCotiocg, L. P.
1936. SOME STORAGE DISEASES OF GRAPEFRUIT. Jour. Agr. Res. 52: 319—
351, illus.
and McCottocHu, lL. P.
1937. SOME EFFECTS OF STORAGE CONDITIONS UPON LEMONS. Jour. Agr.
Res. 55: 795-809, illus.
Camp, A. F., GappuM, L. W., and STAHL, A. L.
1933. COLD STORAGE STUDIES ON CITRUS FRUITS. Fla. Agr. Expt. Sta.
Ann. Rpt. 1932-33 : 104-109.
CARRICK, D. B.
1930. SOME COLD STORAGE AND FREEZING STUDIES ON THE FRUIT OF THE
VINIFERA GRAPE, N. Y. (Cornell) Agr. Expt. Sta. Mem. 181,
37 pp., illus. ;
CooLey, J. S., and CRENSHAW, J. H.
1931. CONTROL OF BOTRYTIS ROT OF PEARS WITH CHEMICALLY TREATED WRAP-
PERS. U.S. Dept. Agr. Cir. 177, 10 pp., illus.
CoRDNER, H. B.
1943. EXPERIMENTS WITH IRISH POTATOES: TIME OF PLANTING; SEED
SOURCES ; VARIETIES } IRRIGATION ; FERTILIZERS ; TIME OF HARVEST;
AND STORAGE OF THE SPRING CROP. Okla. Agr. Expt. Sta. Tech. Bul.
T-18, 27 pp., illus.
DENNY, F. E.
1924, EFFECT OF ETHYLENE UPON THE RESPIRATION OF LEMONS. Bot. Gaz.
77: 322-329, illus.
DIEHL, H. C.
1940. QUICK FREEZING FRUITS [AND] QUICK FREEZING VEGETABLES, Amer.
_ Soe. Refrig. Engin., Refrig. Data Book 2: 19-30, illus.
MAGNESS, J. R., Gross, C. R., and Bonney, V. B.
1930. THE FROZEN-PACK METHOD OF PRESERVING BERRIES IN THE PACIFIC
NORTHWEST. U.S. Dept. Agr. Tech. Bul. 148, 38 pp., illus.
Epear, A. D.
1938. STUDIES OF POTATO STORAGE HOUSES IN MAINE. U.S. Dept. Agr. Tech.
Bul. 615, 47 pp., illus.:
1947. POTATO STORAGE. U.S. Dept. Agr. Farmers’ Bul. 1986, 38 pp., illus.
FISHER, D. F. :
1942. HANDLING APPLES FROM TREE TO TABLE. U.S. Dept. Agr. Cir. 659,
39 pp., illus.
and Coo.Ley, J. S.
1947. APPLE SCALD AND ITS conTROL. U. S. Dept. Agr. Farmers’ Bul.
1380, 9 pp., illus. (Revised.)
FRANKLIN, H. J.
1940. CRANBERRY GROWING IN MASSACHUSETTS. Mass. Agr. Expt. Sta. Bul.
371, 44 pp., illus.
FRIEND, W. H., and Bacu, W. J.
1932, STORAGE EXPERIMENTS WITH TEXAS CITRUS FRUIT. Tex. Agr. Expt.
Sta. Bul. 446, 40 pp., illus.
FRuIT DISPATCH COMPANY, EQUIPMENT DEPARTMENT.
1942, BANANA RIPENING MANUAL. Fruit Dispatch Co., Equipment Dept.
Cir. 14, 20 pp., illus.
56
(26)
(27)
(28)
(29)
(41)
(42)
(43)
(44)
(49)
(46)
CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
GERHARDT, F., and ENGLISH, H.
1945. RIPENING OF THE ITALIAN PRUNE AS RELATED TO MATURITY AND STOR-
AGE. Amer. Soc. Hort. Sci. Proc. 46: 205-209, illus.
and HZELL, B. D.
1941. PHYSIOLOGICAL INVESTIGATIONS ON FALL AND WINTER PEARS IN THE
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1939. THE STORAGE OF SWEET CHERRIES AS INFLUENCED BY CARBON DIOXIDE
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Gore, H. C.
1911. STUDIES ON FRUIT RESPIRATION. I. THE EFFECT OF TEMPERATURE ON
THE RESPIRATION OF FRUITS. II. THE EFFECT OF PICKING ON THE
RATE OF EVOLUTION OF CARBON DIOXIDE BY PEACHES. III. THE RATE
OF ACCUMULATION OF HEAT IN THB RESPIRATION OF FRUIT UNDER
ADIABATIC CONDITIONS. U.S. Bur. Chem. Bul. 142, 40 pp., illus.
GREEN, W. P., HUKILL, W. V., and Ross, D. H.
1941. CALORIMETRIC MEASUREMENTS OF THE HEAT OF RESPIRATION OF FRUITS
AND VEGETABLES. U.S. Dept. Agr. Tech. Bul. 771, 22 pp., illus.
GRIFFITHS, D.
1936. SPEEDING UP FLOWERING IN THE DAFFODIL AND THE BULBOUS IRIS. U.S.
Dept. Agr. Cir. 367, 18 pp., illus.
1936. TULIPS. U.S. Dept. Agr. Cir. 372, 64 pp., illus.
HALLER, M. H., and Harpine, P. L.
1939. EFFECT OF STORAGE TEMPERATURES ON PEACHES. U. S. Dept. Agr.
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HARDING, P. L., Lutz, J. M., and Roskg, D. H.
1932. THE RESPIRATION OF SOME FRUITS IN RELATION TO TEMPERATURE.
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HAMNER, C. L., GARTNER, J. B., and O’RouRKE, F. L.
1948. A NON-TOXIC PLASTIC COATING TO IMPROVE THE KEEPING QUALITY OF
CUT FOLIAGE. Mich. Agr. Expt. Sta. Quart. Bul. 30: 268-271, illus.
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1935. PHYSIOLOGICAL BEHAVIOR OF GRIMES GOLDEN APPLES IN STORAGE. Iowa
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1933. THE INFLUENCE OF STORAGE TEMPERATURES ON THE DESSERT AND KEEP-
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and HAtuer, M. H.
1935. PEACH STORAGE WITH SPECIAL REFERENCE TO BREAKDOWN. Amer. Soc.
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Harvey, HE. M.
1946. CHANGES IN LEMONS DURING STORAGE AS AFFECTED BY AIR CIRCULATION
AND VENTILATION. U.S. Dept. Agr. Tech. Bul. 908, 32 pp., illus.
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1915. RESPIRATION EXPERIMENTS WITH SWEETPOTATOES. Jour. Agr. Res.
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HAWKINS, L. A.
1929. GOVERNING FACTORS IN TRANSPORTATION OF PERISHABLE COMMODITIES.
Refrig. Engin. 18: 130-131, 135.
HENDRICKSON, H. M.
1940, REFRIGERATION OF LEMONS. Amer. Soc. Refrig. Engin., Refrig. Data
Book 2: 174-178, illus.
HUuKILL, W. V., and SmirH, BH.
1946. COLD STORAGE FOR APPLES AND PEARS. U. S. Dept. Agr. Cir. 740,
61 pp., illus.
KImMBprouGcH, W. D.
1944. STORAGE OF IRISH POTATOES IN THE LOWER SOUTH. La. Agr. Expt.
Sta. La. Bul. 386, 17 pp.
LAURITZEN, J. I.
1931. SOME EFFECTS OF CHILLING TEMPERATURES ON SWEETPOTATOES. Jour.
Agr. Res. 42 : 617-627, illus.
and Wricut, R. C.
1930. SOME CONDITIONS AFFECTING THE STORAGE OF PEPPERS, Jour, Agr,
Res. 41 : 295-305, illus.
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 57
LUMSDEN, D. V., Wricut, R. C., WHITEMAN, T. M., and ByrngEs, J. W.
1940. FRUIT AND FLOWERS INCOMPATIBLE, Florists’ Exch, 95 (2):10, 1],
illus.
Lutz, J. M.
1938. FACTORS INFLUENCING THE QUALITY OF AMERICAN GRAPES IN STORAGE.
U. 8. Dept. Agr. Tech. Bul. 606, 27 pp., illus.
1947. STORAGE OF SOUTHERN-GROWN POTATCES DURING THE SUMMER. Amer.
Potato Jour. 24: 209-220, illus.
CULPEPPER, C. W., Moon, H. H., and MEYERS, A. T.
1933. OBTAINING OPTIMUM DESSERT AND CANNING QUALITIES FROM THE
KIEFFER PEAR; SOME INFLUENTIAL FACTORS. Canning Age 14 (10):
404—406, 414, 428, illus.
and Simons, J. W.
1948. STORAGE OF SWEETPOTATOES. U.S. Dept. Agr. Farmers’ Bul. 1442,
50 pp., illus. (Revised. )
LYNCH, S. J., and STAHL, A. H.
1939. STUDIES IN THE COLD STORAGE OF AVOCADOS. Fla. State Hort. Soc.
Proc. 52: 79-81.
Maeness, J. R., and BALLARD, W. S.
1926. THE RESPIRATION OF RARTLETT PEARS. Jour. Agr. Res. 32: 801-832,
illus.
—— DIerH1, H.C., and ALiEn, F. W.
1929. INVESTIGATIONS ON THE HANDLING OF BARTLETT PEARS FROM PACIFIC
coASsT DisTRIcTS. U.S. Dept. Agr. Tech. Bul. 140, 28 pp., illus.
DIEHL, M. C., HALLER, M. H., and others.
1926. THE RIPENING, STORAGE, AND HANDLING OF APPLES. U.S. Dept. Agr.
Dept. Bul. 1406, 64 pp., illus.
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.
MAGRUDER, R., WESTER, R. E., Jonres, H. A., and others.
1941. STORAGE QUALITY OF THE PRINCIPAL AMERICAN VARIETIES OF ONIONS.
U.S. Dept. Agr. Cir. 618, 48 pp.
MILBRATH, J. A., HANSEN, E., and HarTMaAN, H.
1940. DEFOLIATION OF ROSE PLANTS WITH ETHYLENE GAS. Science 91: 100.
NEFF, M. S.
1939. Coren AND KEEPING QUALITIES OF CUT FLOWERS. Bot. Gaz. 101: 501-
U4,
1939. PROBLEMS IN THE STORAGE OF CUT CARNATIONS. Plant Physiol.
14 : 271-284, illus.
and Loomis, W. E.
1936. STORAGE OF FRENCH MARIGOLDS, Amer. Soc. Hort. Sci. Proce. (1935)
33 : 683-685.
OLNEY, A. J.
1926. TEMPERATURE AND RESPiRATION OF RIPENING BANANAS. Bot. Gaz.
82: 415-416, illus.
OVERHOLSER, HL. L.
1925. COLD STORAGE BEHAVIOR OF AvocaDos. Calif. Avocado Assoc. Ann.
Rpt. 1924-25 : 32-40.
PEACOCK, W. M., WRIGHT, R. C., WHITEMAN, T. M., and FULLER, BE.
1931. DIFFERENCES IN THE COOKING QUALITY OF POTATOES DUE TO STORAGE
TEMPERATURES. Potato Assoc. Amer. Proce. (1930) 17: 109-116.
PENTZER, W. T.
1931. THE COLD STORAGE OF GRAPES. Ice and Refrig. 81: 84.
——— and AsBupry, C. E.
1935. THE SODIUM BISULPHITE TREATMENT OF GRAPES TO RETARD MOLD
GROWTH. Blue Anchor 12 (5) :6, 26-27.
and AssBury, C. E.
1937. OBSERVATIONS ON THE COLD STORAGE OF GRAPES AND OTHER FRUITS
DURING THE 1936 SEASON. Ice and Refrig. 93: 193-194.
Magness, J. R., Dient, H. C., and Hater, M. H.
1932. INVESTIGATIONS ON HARVESTING AND HANDLING FALL AND WINTER PEARS,
U.S. Dept. Agr. Tech. Bul. 290, 30 pp., illus.
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CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
PENTZER, W. T., PERRY, R. L., HANNA, G. C., and others.
1936. PRECOOLING AND SHIPPING CALIFORNIA ASPARAGUS. Calif. Agr. Expt.
Sta. Bul. 600, 45 pp.. illus.
WIANT, J. S., and MacGiitivray, J. H.
1940. MARKET QUALITY AND CONDITION OF CALIFORNIA CANTALOUPS AS IN-
FLUENCED BY MATURITY, HANDLING, AND PRECOOLING. U. S. Dept.
Agr. Tech. Bul. 730, 74 pp., illus.
PLAGGE, H. H.
1940. COLD STORAGE OF APPLES AND PEARS. Amer. Soc. Refrig. Engin.,
Refrig. Data Book 2: 163-170, illus.
and Maney, T. J.
1928. SOGGY BREAKDOWN OF APPLES AND ITS CONTROL BY STORAGE TEMPERATURE.
Iowa Agr. Expt. Sta. Res. Bul. 115, pp. 63-118, illus.
and Maney, T. J.
1987. FACTORS INFLUENCING THE DEVELOPMENT OF SOGGY BREAK-DOWN IN
APPLES. Jour. Agr. Res. 55: 739-768, illus.
MANEY, T. J., and PICKETT, B. S.
1935. FUNCTIONAL DISEASES OF THE APPLE IN STORAGE. Iowa Agr. Expt.
ta. Bul. 329, 79 pp., illus.
PLATENIUS, H.
1939. WAX EMULSIONS FOR VEGETABLES. N. Y. (Cornell) Agr. Expt. Sta.
Bul. 723, 43 pp., illus.
JAMISON, F. S., and THoMpPSoON, H. C.
1934. STUDIES ON COLD STORAGE OF VEGETABLES. N. Y. (Cornell) Agr. Expt.
Sta. Bul. 602, 24 pp., illus.
RAMSEY, G. B., and Link, G. K. K.
1982. MARKET DISEASES OF FRUITS AND VEGETABLES : TOMATOES, PEPPERS, EGG-
PLANTS. U.S. Dept. Agr. Mise. Pub. 121, 44 pp., illus.
and WIANT, J. S.
1944. MARKET DISEASES OF FRUITS AND VEGETABLES : BEETS, ENDIVE, ESCAROLE,
GLOBE ARTICHOKES, LETTUCE, RHUBARB, SPINACH, SWISS CH ARD, and
SWEETPOTATOES. U.S. Dept. Agr. Misc. Pub. 541, 40 pp., illus.
WIANT, J. S., and LINK, G. K. K.
1938. MARKET DISEASES OF FRUITS AND VEGETABLES: CRUCIFERS AND CUCUR-
BITS. U.S. Dept. Agr. Mise. Pub. 292, 74 pp., illus.
WIANT, J. S., and SmitH, M. A.
1949. MARKET DIEASES OF FRUITS AND VEGETABLES: POTATOES. U. S. Dept.
Agr. Mise. Pub. 98, 60 pp., illus. (Revised.)
RASMUSSEN, E. J.
1937. EFFECT OF DELAY IN STORAGE TEMPERATURE ON THE KEEPING QUALITIES
OF APPLES. N. H. Agr. Expt. Sta. Tech. Bul. 67, 55 pp., illus.
Rose, D. H., BRATLEY, C. O., and PENTZER, W. T.
1939. MARKET DISEASES OF FRUITS AND VEGETABLES : GRAPES AND OTHER SMALL
FRUITS. U.S. Dept. Agr. Misc. Pub. 340, 27 pp., illus.
Brooks, C., BRATLEY, C. O., and WINSTON, J: R.
1944. MARKET DISEASES OF FRUITS AND VEGETABLES: CITRUS AND OTHER SUB-
TROPICAL FRUITS. U.S. Dept. Agr. Misc. Pub. 498, 57 pp., illus.
Brooks, C., FISHER, D. F., and BRATLEY, C. O.
1933. MARKET DISEASES OF FRUITS AND VEGETABLES : APPLES, PEARS, QUINCES.
U. S. Dept. Agr. Mise. Pub. 168, 71 pp., illus.
FISHER, D. F:, Brooxs, C., and BRATLEY, C. O.
1937. MARKET DISEASES OF FRUITS AND VEGETABLES : PEACHES, PLUMS, CHER-
RIES, AND OTHER STONE FRUITS. U.S. Dept. Agr. Misc. Pub. 228,
27 pp., illus.
SHAPOVALOY, M., and LINE, G. K. K.
1926. CONTROL OF POTATO-TUBER DISEASES. U. S. Dept. Agr. Farmers’
Bul. 1367, 38 pp., illus. (Revised.)
SHERWOOD, C. H., and HAMNER, C. L.
1948. LENGTHENING THE LIFE OF CUT FLOWERS AND FLORAL GREENS BY THE
USE OF PLASTIC COATINGS. Mich. Agr. Expt. Stat Quart. Bul. 30:
272-276, illus.
SIEBEL, J. E.
1918. COMPEND OF MECHANICAL REFRIGERATION AND ENGINEERING ... Ed.9,
571 pp., illus. Chicago.
Srevers, A. F., and Barcer, W. R.
1930. E¥YPERIMENTS ON THE PROCESSING AND STORING OF DEGLET NOOR DATES
IN CALIFORNIA. U. S. Dept. Agr. Tech. Bul. 193, 24 pp., illus.
AA
STORAGE OF FRUITS, VEGETABLES, AND FLORISTS’ STOCKS 59
(90) Smock, R. M.
1940. THE STORAGE OF APPLES. N. Y. Agr. Col. (Cornell) Ext. Bul. 440,
38 pp., illus.
and SouTHWICcK, F. W.
1948. AIR PURIFICATION IN THE APPLE STORAGE. N. Y. (Cornell) Agr. Expt.
Sta. Bul. 848, 52 pp., illus.
(92) StTaut, A. L., and CAIN, J. C.
1937. COLD STORAGE STUDIES OF FLORIDA CITRUS FRUITS. III, THE RELATION OF
STORAGE ATMOSPHERE TO THE KEEPING QUALITY OF CITRUS FRUIT IN
COLD STORAGE. Fla. Agr. Expt. Sta. Bul. 316, pp. 3-41, illus.
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(93) and Camp, A. F.
1936. COLD STORAGE STUDIES OF FLORIDA CITRUS FRUITS. I. EFFECT OF TEM-
PERATURE AND MATURITY ON THE CHANGES IN COMPOSITION AND
KEEPING QUALITY OF ORANGES AND GRAPEFRUIT IN COLD STORAGE.
Fla. Agr. Expt. Sta. Bul. 303, 67 pp., illus.
(94) and Firirip, W. M.
1936. COLD STORAGE STUDIES OF FLORIDA CITRUS FRUITS. II, EFFECT OF VARIOUS
WRAPPERS AND TEMPERATURES ON THE PRESERVATION OF CITRUS FRUITS
IN STORAGE. Fla. Agr. Expt. Sta. Bul. 304, 78 pp., illus.
(95) THOMPSON, H. C.
1917. CELERY STORAGE EXPERIMENTS. U.S. Dept. Agr. Bul. 579, 26 pp., illus.
(96) TRESSLER, D. K., and Evers, C. F.
1936. THE FREEZING PRESERVATION OF FRUITS, FRUIT JUICES, AND VEGETABLES.
369 pp., illus. New York.
(97) VINCENT, C. C., VERNER, L., and BLODGETT, EF. C.
1929. PROGRESS REPORT OF PRUNE STORAGE AND MATURITY STUDIES. Idaho
Agr. Expt. Sta. Bul. 167, 19 pp., illus.
(98) WALKER, J. C.
1947. ONION DISEASES AND THEIR CONTROL. U.S. Dept. Agr. Farmers’ Bul.
1060, 26 pp., illus. (Revised.)
(99) WarpLaw, C. W.
1934. PRELIMINARY OBSERVATIONS ON THE STORAGE OF AVOCADO PEARS. ‘Trop.
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(100) and Lronarp, EH. R.
1935. THE STORAGE OF AVOCADO PEARS. Trop. Agr. [Trinidad] 12: 132-1383.
(101) LEONARD, E. R., and BAKER, R. E. D.
19384. OBSERVATIONS ON THE STORAGE OF VARIOUS FRUITS AND VEGETABLES.
I. TOMATOES, CAULIFLOWERS, STRING BEANS, EGGPLANT, CUCUMBERS,
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(102) LEONARD, HE. R., and BAKER, R. E. D.
1934. OBSERVATIONS ON THE STORAGE OF VARIOUS FRUITS AND VEGETABLES.
II. PAPAWS, PINEAPPLES, GRANADILLAS, GRAPEFRUIT, AND ORANGES.
Trop. Agr. [Trinidad] 11: 230-235.
(103) = LEONARD, EH. R., and BARNELL, H. R.
1939. METABOLIC AND STORAGE INVESTIGATIONS ON THE BANANA. ‘Trinidad
Imp. Col. Trop. Agr. Low Temp. Res. Sta. Mem. 11, 61 pp., illus.
(104) WHiItTEMaN, T. M.
1932. COMMERCIAL FORCING OF LILIES-OF-THE-VALLEY. U.S. Dept. Agr. Cir.
215, 20 pp., illus.
(105) and McCLELLAN, W. D.
1946. TIP CURVATURE OF CUT GLADIOLI. Amer. Soc. Hort. Sci. Proc. 47 : 515—
521, illus. : i
(106) and WRIGHT, R. C.
1939. STORAGE OF WEDGWOOD IRIS BLOOMS. Florists’ Exch. 92 (14) : 16.
(107) WRIGHT, R. C., and GRIFFITHS, D.
1934. THE STORAGE OF TULIP BLOOMS. Florists’ Exch. 82 (3): 11, 14.
(108) WariGut, R. C., and GRIFFITHS, D.
1935. THE FORCING OF PAPER WHITE NARCISSUS BULBS AFTER STORAGE AT VARI-
OUS TEMPERATURES. Amer. Soc. Hort. Sci. Proce. (1934) 32:
645-650.
(109) Wrant, J. S.
1937. INVESTIGATIONS OF THE MARKET DISEASES OF CANTALOUPS AND HONEY
DEW AND HONEY BALL MELONS. U. S. Dept. Agr. Tech. Bul. 573,
48 pp., illus.
(110) WititamMs, L. J.
1933. COLD STORAGE OF PINEAIPLES AND PINEAPPLE JUICE. Ice and Refrig.
85 : 25-26.
60
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CIRCULAR 278, U. S. DEPARTMENT OF AGRICULTURE
WINSTON, J. R.
1935. REDUCING DECAY IN CITRUS FRUITS WITH BORAX. U. S. Dept. Agr.
Tech. Bul. 488, 32 pp., illus.
1936. A METHOD OF HARVESTING GRAPEFRUIT TO RETARD STEM-END ROT. U.S.
Dept. Agr. Cir. 396, 8 pp., illus.
1937. HARVESTING AND HANDLING CITRUS FRUITS IN THE GULF STATES. U. S.
Dept. Agr. Farmers’ Bul. 1768, 38 pp., illus.
WINTER, J. D., and ALDERMAN, W. H.
1935. PICKING, HANDLING, AND REFRIGERATION OF RASPBERRIES AND STRAW-
BERRIES. Minn. Agr. Expt. Sta. Bul. 318, 39 pp., illus.
WOLFE, H. S., Toy, L. R., and STAHL, A. L.
1946. AVOCADO PRODUCTION IN FLORIDA. Fla. Agr. Col. Ext. Bul. 129,
107 pp., illus.
WRIGHT, R. C. -
1937. THE FREEZING TEMPERATURES OF SOME FRUITS, VEGETABLES, AND
FLORISTS’ sTocKsS. U.S. Dept. Agr. Cir. 447, 11 pp.
1941. INVESTIGATIONS ON THE STORAGE OF NUTS. U. S. Dept. Agr. Tech.
Bul. 770, 35 pp., illus.
DEMAREE, J. B., and Witcox, M. §S.
1937. SOME EFFECTS OF DIFFERENT STORAGE TEMPERATURES ON THE KEEPING
OF CRANBERRIES. Amer. Soc. Hort. Sci. Proc. (1936) 34: 897-401,
illus. ;
and GORMAN, E. A.
1940. THE RIPENING AND REPACKING OF MATURE-GREEN TOMATOES. U. S.
Dept. Agr. Cir. 566, 8 pp., illus.
PEACOCK, W. M., WHITEMAN, T. M., and WHITMAN, Hb. F.
1936. THE COOKING QUALITY, PALATABILITY, AND CARBOHYDRATE COMPOSITION
OF POTATOES AS INFLUENCED BY STORAGH TEMPERATURE. U. S. Dept.
Agr. Tech. Bul. 507, 20 pp., illus.
PENTZER, W. T., WHITEMAN, T. M., and Ross, D. H.
1931. EFFECT OF VARIOUS TEMPERATURES ON THE STORAGE AND RIPENING OF
TOMATOES. U. S. Dept. Agr. Tech. Bul. 268, 35 pp., illus.
and WHITEMAN, T. M.
1931. DETERIORATION OF CHRISTMAS HOLLY IN TRANSIT AND STORAGE. U. S.
Dept. Agr. Cir. 207, 12 pp., illus.
and WHITEMAN, T. M.
1949. A PROGRESS REPORT ON THE CHIPPING QUALITY OF 33 POTATO VARIETIES.
Amer. Potato Jour. 26: [117]-120.
U.S. GOVERNMENT PRINTING OFFICE: 1949
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