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RETAIL STORES

Agriculture Handbook No. 117

U. S. DEPARTMENT OF AGRICULTURE

Washington, D. C.
CONTENTS

Page

Prepackaging 1

Effect of previous history on shelf

life 2

Care of produce on arrival at retail

store 3

Rough handling lowers quality... 3

Importance of quality to impulse

buying 3

Washing produce 4

Fruit and vegetable display cases. 4

Mechanically refrigerated by

convection or gravity-flow. 4

Mechanically refrigerated by

forced-circulation 5

Ice-bed case.. 5

Nonrefrigerated case 5

Temperatures in display cases. . . 6

Overnight storage 7

Storage of reserve supplies 8

Moisture control important 9

Temperature requirements 14

Apples 15

Apricots 16

Artichokes 16

Asparagus 16

Avocados 16

Bananas 17

Beans, lima 17

Beans, snap 17

Beets 17

Berries 18

Broccoli (Italian or sprouting) 18

Brussels sprouts 19

Cabbage 19

Carrots 19

Cauliflower 20

Celery 20

Cherries 20

Collards 20

Corn, sweet 21

Cranberries 21

ACKNOWLEDGMENTS

Page

Temperature requirements—Con.

Cucumbers 21

Dates 21

Eggplant 21

Endive 22

Figs, fresh 22

Grapefruit 22

Grapes 22

Kale 22

Leeks, green 23

Lemons 23

Lettuce 23

Limes (Tahiti) 23

Mangoes 24

Melons 24

Mushrooms, cultivated 24

Nectarines 24

Okra 24

Onions, dry 25

Onions, green 25

Oranges 25

Parsnips 25

Peaches 26

Pears 26

Peas, green 26

Peppers, green 26

Persimmons 27

Pineapples 27

Plums (including prunes) 27

Potatoes 27

Pumpkins and squashes 28

Radishes 28

Raspberries 28

Rhubarb 28

Shallots 29

Spinach 29

Squashes 29

Strawberries 29

Sweetpotatoes 29

Tangerines 29

Tomatoes 30

Turnips and rutabagas 30

Material in this handbook is based principally 6n studies of

the shelf life of many different fresh fruits and vegetables displayed in several retail-store types of cases, and from material

published in U. S. Department of Agriculture Handbook No. 66,

"The Commercial Storage of Fruits, Vegetables, and Florist and

Nursery Stocks/' The writer has drawn freely from published

and unpublished findings of other staff members and from personal observations of handling practices in various producing

areas and destination markets and their relation to quality and

condition standards for various fresh fruits and vegetables.

Issued March 1957

For sale by the Superintendent of Documents, U. S. Government Printing Office

Washington 25, D. C. - Price 15 cents
MAINTAINING PRODUCE QUALITY

IN RETAIL STORES

By WILLIAM E. LEWIS, senior horticulturist. Quality Maintenance and Improvement

Section, Biologicfd Sciences Branch, Marketing Research Division

The retail store operator plays a very important part in the marketing

of fresh fruits and vegetables. He is the last link in the long chain of

handlers and is the only person with whom the consumer has direct

contact. Unless the retailer offers fresh fruits and vegetables in a

satisfactory condition to the consumer, direct or indirect losses may

reflect back through each handler to the grower. The retail operator

can do a great deal to protect the quality of produce.

Fresh fruits and vegetables displayed in retail stores are living on

'^borrowed time." Aging and other deterioration are continuous processes, the rate depending upon the commodity and the conditions under

which it is held. Most fruits and vegetables are near or at the prime of

life when harvested. They continue to live even after separation from the

parent plants. The length of the post-harvest life depends largely

upon temperature, moisture, and care in physical handling of the commodity. Cooling generally slows down aging and development of decay.

Proper humidity aids in preventing loss of moisture that is essential to

the living cell. Careful handling reduces unattractive bruises and broken

skins that provide openings for decay organisms.

The purpose of this handbook is to provide information regarding

desirable temperature and moisture conditions for daytime display,

overnight holding, and storage of reserve supplies for short periods.^

General principles are discussed and recommendations made for holding

individual commodities under conditions that will aid retail-store operators

in reducing losses and offer the consumer fresh, attractive produce.

Many details are necessarily omitted. The information given should not

be considered absolute or final but rather as a guide in handling the

various products in retail stores.

Prepackaging

Prepackaging of various kinds of fresh fruits and vegetables has

increased during recent years although most produce is still displayed in

* Information relative to extended storage is given in U. S. Dept. Agr. Handbook

No. 66, The Commercial Storage of Fruits, Vegetables, and Florist and Nursery

Stocks. Sept. 1954.
bulk in retail stores.^ Some kinds of produce, such as tomatoes in

cardboard trays, and individual heads of lettuce are overwrapped in

film; others, such as berries, brussels sprouts, and shelled lima beans,

may be in trays or baskets with film-caps; and produce such as potatoes

and oranges is prepackaged in film, paper, or mesh bags. Produce is

frequently unitized in open containers or tied in bunches of the size most

consumers want. Asparagus, celery hearts, and bananas may be tied

or banded as individual consumer units; grapes may be displayed in

open trays, and peaches in small open till baskets; and berries are displayed in small, open or film-capped baskets.

The shelf life of different prepackaged items varies considerably even

under the best temperature and humidity conditions. For example,

the shelf life of prepackaged carrots and radishes is longer than that of

bulk carrots and radishes because the highly penshable tops have been

removed and the roots protected in moisture-retentive bags. The

reverse is true of cut beans and shredded cabbage which need refrigeration

more than the uncut form. Most recommendations given in this handbook concerning temperature and humidity requirements and display

practices for bulk produce apply also to prepackaged produce. Obviously,

the recommendations for sprinkling with water do not apply to prepackaged produce.

Eflfect of Previous History on Shelf Life of Produce

The previous history of the produce has an important effect upon the

length of time it will remain in salable condition in the retail store. Poor

growing conditions, delays in moving produce through marketing channels,

and rough handling often result in shortened shelf life of fresh fruits and

vegetables. Excessive rainfall or long periods of drought, or very hot or

very cold weather during the growing season, may cause injuries to produce before it is harvested. These injuires may or may not be visible.

Delays in moving produce through various handling and shipping operations provoke common and sometimes unavoidable situations that result

in aging and other deterioration of fresh fruits and vegetables. Produce

held too long in cold storage deteriorates rapidly on removal to higher

temperatures. Careless or indifferent physical handling of packed containers often causes excessive bruises or severe cuts or breakage of tender,

highly perishable produce. Produce that is sensitive to cold and has

been subjected to an accumulation of low temperatures previous to arrival

at the retail store will develop chilling injury quicker under unfavorable

refrigeration at the store than produce grown and marketed during warm

weather. Such unfavorable conditions often are the cause of wide varia2 Donald R. Stokes, Marketing Research Division, AMS, in a report presented at

American Management Association Prepackaging Conference, Chicago, 111., April

1955, statesthat estimatesindicate that only about 20 percent offresh fruits and vegetables are marketed in consumer packages.
tions in the keeping quality of fresh fruits and vegetables at the retail

store.

Care of Produce on Arrival at Retail Store

Fresh produce is subject to deterioration when allowed to remain in the

hot sun for several hours or exposed to freezing temperatures on receivers'

platforms. Produce that needs refrigeration should be placed in cold

rooms as soon as possible after arrival at the store, and those commodities

that may be injured by chilling should be moved to rooms with suitable

temperatures.

Rough Handling Lowers Quality

The seriousness of rough handling of fresh produce cannot be overemphasized. Rough handling, whether occurring in the field, in and out of

packinghouses, trucks, railroad cars, wholesale produce houses, or in retail

stores, may result in considerable damage to fresh fruits and vegetables.

Throwing produce into picking or shipping containers, packing containers

too tightly or too loosely, or dropping packed containers often result in

serious damage to the quality and condition of the commodity. Too

often produce that has received the best of care regarding temperature

and moisture is so carelessly handled that badly bruised, cut, or broken

and decayed specimens are found when the package is unpacked at the

retail store.

Rough handling of produce during preparation for display and when

removed from the racks at night and careless handling by customers frequently result in serious loss of quality. When produce is arranged

on the display racks it should be placed, not thrown, into position.

Throwing produce onto the racks sometimes causes bruises and cuts that

are not apparent at the time; it may become soft, discolored, and possibly

decayed. Rough handling by the customer may be lessened to a considerable extent by arranging the produce on the racks so that selections

can be made without digging into the display. Frequent picking over of

produce by customers causes such an accumulation of bruises and other

injuries that the display suffers loss of quality and becomes unattractive.

Importance of Quality to Impulse Buying

Impulse buying of fresh fruits and vegetables by the consumer depends

upon the attractiveness of the display. The effect of mass display or

attractive prices may be dulled by the presence of wilted, shriveled,

spotted, or decayed produce. A single decayed fruit or vegetable in the

display may create doubt in the mind of the customer regarding the

keeping quality of the remainder of the lot. To induce impulse buying,

displays should be free from decay and unsightly discoloration; and the

produce should look clean, fresh, and attractive.
Washing Produce

Washing produce to maintain and improve quality before it is placed

on the display racks is practiced in many retail stores. Washing not only

cleans but "freshens" produce. Rough handling during washing operations should not be permitted. Reasonable care will lessen unsightly

bruises, cuts, and broken stems and leaves. The washing water should

be kept clean to prevent spreading disease organisms throughout the lot.

Fruit and Vegetable Display Cases

Various methods are used to maintain desirable temperatures of fresh

fruits and vegetables in retail stores. Mechanically refrigerated and icebed cases maintain desirable temperatures during both day and night,

while produce displayed in nonrefrigerated cases during the daytime may

be stored at night in fruit and vegetable storage rooms or in iced produce

barrels.

There are many different types of mechanically refrigerated display

cases, including open and closed convection or gravity-flow, and forcedcirculation types. Closed cases may be used advantageously in stores

where the produce is often held for several days before it is sold. In this

type of case, temperatures and moisture are more easily controlled than

in open cases because the produce is less subject to drafts and changes in

display room atmosphere. The open-top case is more suitable for stores

that have a rapid turnover and where it is desirable to have the produce

more readily accessible to the customer.

Mechanically refrigerated by convection or gravity-flow

In the open convection-type case, refrigeration of produce is based on

the principle that cold air sinks and warm air rises. As air passes over

refrigerated coils and is cooled, it sinks to the bottom of the case, passes

under and up through the display where it is warmed by heat removed

from the produce. This warmed air flows back over the refrigerated

coils where it is re-cooled and follows the path of the cold air preceding

it.

Temperatures in the convection-type case depend upon the depth and

the distance of the produce from the coils. The practice of displaying

produce on wooden boxes, crates, or inverted baskets to raise the display

results in the produce being placed farther from and insulated against the

source of refrigeration. Accordingly, higher temperatures occur in

produce displayed on these false racks than in produce displayed on

the regular rack supplied with the case, as will be discussed later. Slow

moving produce should not be piled above the top front edge of convectiontype cases. High temperatures may be expected in the upper layer when

the produce is piled too high on the racks. Covering produce at night

with wet canvas or heavy paper will aid in pr^jventing loss ofmoisture and

refrigeration.
Mechanically refrigerated by forced-circulation

In the mechanically refrigerated case with forced-ciiculation, fans move

the air over and through the produce from which heat is picked up.

The air then returns through ducts to the refrigerated coils where it is

re-cooled and re-circulated. The forced circulation of cold air over the

top of the produce permits the display of produce in a desirably high,

prominent position in the case. This air-flow over the top layer, however,

may cause some wilting, especially if the fan speed is too great. Allen

and Pentzer ^ found that doubling the rate of air movement increased

moisture loss by about one-third. Moisture loss may be minimized by

sprinkling the produce with water several times daily. Covering the

produce at night with wet canvas or heavy paper will lessen wilting or

drying. The covering should be arranged so that the circulation of air

is not obstructed.

Ice-bed case

Low temperatures and high humidity are readily obtained with proper

use of the ice-bed case. Arrange the produire on a 3- to 5-inch bed of

crushed ice each morning and then cover it immediately with a thick

layer of ice for best results. Much of this garnish ice will soon melt and

leave the produce fresh and crisp when the early customers arrive. At

noon and at midafternoon, a light garnish of ice will keep the produce

cool and moist. In some stores the produce is sprinkled with water

instead of being garnished with ice during the daytime. Although

sprinkling retards wilting and drying, it does not cool the produce in

the upper layers, and water from sprinkling, especially if heavily applied,

will melt some of the ice in the bed of the case. Whether garnished with

ice or sprinkled with water, a thick layer of ice should be spread over

the produce when it is prepared for night storage, and the whole covered

with canvas or heavy paper. Produce garnished with ice or sprinkled

with water usually increases in weight (table 1).

Nonrefrigerated case

Nonrefrigerated cases may be used to display continuously fruits and

vegetables that do not need refrigeration or that may be injured by low

temperatures; these cases may also be used for other produce that is

stored at night in iced produce barrels or in cold storage rooms. Most

fruits and vegetables that will be sold during the first day may be displayed without refrigeration, but produce that does best at low temperatures should be kept as cool as available refrigeration will permit. In

some stores, a thin layer of crushed ice is spread over the top ofthe produce

but no ice is used underneath. This method is intermediate between the

' Allen, F. W., and Pentzer, W. T. Studies on the effect of humidity in the cold

storage of fruits. Amer. Soc. Hort. Sei. Froc., 33: 215-223, illus., 1936.
TABLE 1.- -Weight changes in produce as affected by different handling

practices in an ice-bed case

Commodity

Beans, snap

Beets, bunched. . .

Broccoli, sprouting

Carrots, bunched. .

Cauliflower

Cucumbers

Lettuce

Onions, green

Radishes, bunched.

Weight change of produce

Garnished with

ice 3 times daily

and covered witn

thick layer of ice

at night

1

day

Pet,

+ 1

+5

0

+ 1

+2

0

+ 1

+4

+ 4

2

days

Peí.

+4

4-7

+ 1

+3

+3

0

+ 1

+6

+6

3

days

Pet,

+ 6

+8

+ 1

+5

+3

0

+ 1

+7

+ 5

Sprinkled with

tap-water 3

times daily and

covered with

thick layer of ice

at night

1

day

Pet,

4-1

+4

4-2

4-2

+2

0

+ 1

4-3

4-3

2

days

Pet.

+4

-f6

4-4

+3

-h2

0

-hi

4-5

4-3

3

days

Pet,

-f5

+ 8

+5

+3

-1-3

0

4-1

+ 7

4-4

Not garnished or

sprinkled days

but covered with

thick layer of ice

at night

1

day

Pet,

0

-fl

-1

0

0

0

0

0

0

2

days

Pet,

4-1

4-1

-1

0

-1

0

0

-h2

-h2

3

days

Pet,

4-1

-f3

-1

0

-1

0

-1

-1-3

-1-2

usual practice followed in using the ice-bed case, and that of displaying

produce without refrigeration during the daytime. Garnish ice spread

over produce displayed on a nonrefrigerated rack provides some cooling,

and water from melting ice provides moisture that minimizes wilting and

drying of the produce. Tests by Hansen and McColloch * showed that

the average produce temperature of about 58"* F. was low enough to check

somewhat the development of spoilage, but after 2 days the quality deteriorated faster than in the ice-bed case where ice beneath the produce

resulted in lower temperatures.

Temperatures in Display Gases

Refrigeration slows respiration in fresh fruits and vegetables. Generally, the lower the respiration, the slower the loss of quality. Produce

displayed in retail stores, however, does not require the low temperatures

needed for extended storage. Temperatures of 40° to 50° F. will keep most

produce in satisfactory condition for 3 or 4 days.

Loss from unnecessary deterioration of fresh fruits and vegetables may

be reduced if produce temperatures in different parts of display cases are

known. Although temperatures often found in the lower layer in refrigerated display cases are highly desirable for some kinds of produce, they

cu* Sî'îr'^'i.Î; ^'\ ÏÎ** McColloch, L. P. Effect of Temperature and Moisture on the

Shelf Life of Fresh Produce. U. S. Bur. Plant Indus., Soils, and Agr. Eng. Handling,

Transportation & Storage Off. Rpt. No. 213, 13 pp., illus. July 1949.
may cause chilling injury to others that are sensitive to temperatures

below 40° F.

The differences in temperatures of produce displayed in several types

of cases, at various positions, are given in figure 1. Temperatures of produce displayed in the ice-bed case and in both types of mechanically refrigerated cases were materially higher in the top layer than in the bottom.

In the convection-type case, temperatures of produce displayed on a

raised false rack were considerably higher than those of produce on the

regular rack. Temperatures in the top layer on the false rack were only a

few degrees lower than that of produce displayed continuously without

refrigeration.

The depth to which produce is piled in a display case may cause wide

variations in the temperatures between the bottom and top layers.

Differences of 25 to 30 degrees between the 2 layers have been noted in

produce piled 12 inches deep. The temperatures of produce in various

positions when piled at different depths in the display case are shown in

the cross-section diagrams in figure 2.

Relatively high temperatures in produce displayed continuously

without refrigeration, or in the top layer on raised false racks in convection-type cases, favor decay and rapid deterioration of lettuce, bunched

beets, and other kinds of produce that require low temperatures for best

shelf life.

Overnight Storage

Fruit and vegetable storage rooms and iced barrels may be used to

refrigerate produce during the night after daytime display without refrigeration. The cooling effect of night refrigeration carries well into

the following day when the produce is displayed again on nonrefrigerated

racks (fig. 3). Tests have shown that the average daytime temperatures

of produce held overnight in 32° and 40° F. storage rooms averaged 13

and 15 degrees, respectively, below the average temperatures of produce

displayed continuously without refrigeration. The average 24-hour

temperature of produce held overnight in a 40° storage room, or in an

iced barrel, averaged approximately 50° and that of produce stored in a

32° room, averaged about 45°. These 24-hour temperatures were approximately 20 and 25 degrees, respectively, below the average 24-hour

temperatures of produce held continuously without refrigeration.

Iced produce barrels (fig. 4) may be used to refrigerate produce during

the night. A stout wooden barrel or metal drum,^ provided with a

drain and a slatted false bottom, is suitable for this purpose. A barrel of

about 50 gallons capacity will hold 100 to 125 pounds of produce in

addition to the ice. Two or three inches of crushed ice is spread over the

slatted rack in the bottom. The barrel is then filled with alternate

layers of produce and crushed ice, and a wet burlap sack or other suitable

5 Average temperatures of produce held overnight in the wood barrel and the metal

drum varied less than 1 degree.

417201 0—57-
material is placed over the top. About 10 to 12 pounds of ice is used in

the bottom, 6 to 8 pounds between layers, and about 12 pounds over the

top layer of produce. This will require from 50 to 90 pounds of ice daily.

The packed barrel of produce may be left in the display room during the

night.

Produce stored overnight in the iced barrel increased in weight more

than that held at night in a storage room at 40° F. (table 2).

Storage of Reserve Supplies

For short storage of reserve supplies (generally less than one week),

fresh fruits and vegetables may be classed into two groups based on

NONREFRIGERATED RETAIL-STORE DISPLAY CASE

-»o...«

.0-'^

.6^°'

r^''^'^^^^^^^^^^ r^%''¿00^^¿^A6-

^AA"'

No refrigeration. Aver- No refrigeration during No refrigeration during

age temperature of prod- day; in storage room at day; in 40° storage room

uce, ÎO^'FJ 32** F. during night. Av- at night. Average 24-

erage 24-hour temperature hour temperature of proof produce, 46°. duce, 51*".

OPEN, MECHANICALLY REFRIGERATED CASES

{Produce sprinkled with tapwater 4 times daily and covered with heavy paper at night.)

Convection or Gravityflow Type Forced-Circulation Type

/ PRODUCE

troduce on raised or false

rack. Average temperature of produce, 60° F.

PRODUCE

-50'-

.39**-

Regular rack has slight

slope from front to back

of case. Average temperature of produce, 43°

F.

Produce rack slopes from

about 1 inch at front to 12

inches at back. 'Average

temperature of produce,

43° F.

8
ICE-BED CASE

{Produce covered with thick layer of ice at night)

.4^"- •••• — tf-C

Produce garnished with

ice during day. Average

temperature of produce,

42° F.

Produce sprinkled with

tapwater during day.

Average temperature of

produce, 47° F.

Produce not sprinkled

with water or garnished

with ice during day. Average temperature of

produce, 47° F.

Figure 1.—Effect of position in display case on temperature of 8 to 13 fruits and vegetables piled 6 to 8 inches deep. Temperatures were taken during 18 to 4^ testing

periods. The weekly temperature of the display room ranged from 74 to 77 J^.,

and averaged 75°.

temperature requirements. The first group should include kinds of

produce that require refrigeration, and the second those that may be held

m satisfactory condition at room temperatures (65° to 75 F.) for several

days. A cold storage room equipped to provide temperatures of 40

to 45° could be used for the first group, while ordinary room temperatures

would be satisfactory for such commodities as potatoes, sweetpotatoes,

winter squash, and bananas.

Meat coolers provide the only available refrigeration m some of the

smaller stores. Some, fresh produce might be seriously damaged by

freezing or chilling if stored at temperatures suitable for preservmg meat.

Produce that requires some refrigeration but is sensitive to temperatures below 45° F. if exposed to them for several days, may be held

overnight in a 40° room. A brief summary indicating the smtabihty ot

different temperatures for various commodities held for a short period

in retail stores is given in table 3. . j

Where different kinds of produce are stored together for more than a day

or so, a cross-transfer of odors may be expected. Combinations that may

result in a transfer of odors are apples with celery, cabbage, potatoes, and

onions; celery with onions; and citrus fruits with any of the strong y

scented vegetables. Odors from apples, onions, and other strongly

scented produce are readily absorbed by dairy products. Pears and apples

take on an earthy fiavor when stored with potatoes.

Moisture Control Important

The living cells of fresh fruits and vegetables consist mostly of waterwater essential to the life of the cell and to the preservation of a fresh.
NONREFRIGERATED CASE

6rH T.,

1

Produce in A, B, and C is displayed without refrigeration during the day, and is stored

in 45° to 50° F. room at night.

ICE-BED CASE

..5J° .

9

\^^^

Produce in D, E, and F is garnished with crushed ice 3 times a day and is covered with

a thick layer of ice and heavy paper at night.

MECHANICALLY REFRIGERATED CASE

Open top, convection type

o' \

\

...•^^°-

.——

51°

63°-\

-42°- — 43°—1

1

9

1.

Produce in G, H, and I is sprinkled with tapwater 4 times daily and covered with heavy

paper at night.

Figure 2.—Effect of depth to which fruits and vegetables are piled in the retail-store

display case on temperature of the produce. Temperatures are averages of 12 to 17

daytime readings at each position over a period of 4 to 5 days. Display room air

temperatures ranged from 75° to 84° F., and averaged 81°. The dotted line represents the top of the produce, and the dash line the rack on which produce is placed.

Depth of produce on the racks is indicated at left of each diagram.

tasty, succulent commodity. With some kinds of produce, such as

onions, drying is necessarily a part of the curing process, but with most

fresh fruits and vegetables loss of moisture results in wilting and drying

that detracts from the appearance and general quality of the commodity

and may also result in loss of nutritional value.

Retention of moisture in fresh produce can be aided by control of moisture in the surrounding air. When the relative humidity is low, the com10
TABLE 2.—Effect on weight of produce of storing at night in metal barrel^

in tvood produce barrel, and 40^ F, storage room, after daytime displaywithout refrigeration^

Commodity

Gain or loss in weight of produce displayed on nonrefrigerated rack during day, sprinkled 4 times daily,

and stored at night in—

Metal produce

barrel after being

displayed—

Wood produce

barrel after being

displayed—

40° F. room

after bemg

displayed—

1

day

Beans, green

Broccoli

Cabbage

Carrots, bunched.

Cauliflower

Lettuce

Onions, green. . . .

Average. .

Pet. Í+3

1+4

+5

+4

+ 1

-fl Í+ 4

1 +4

>2

+2

Í +3

1+2

+2

+2.8

2

days

Pet.

+5

+ 7

+ 7

+4

+ 1

+ 1

+5

+6

+3

+3

+ 5

+3

+4

+4.2

3

days

1

day

Pet.

+ 7

+ 11

+8

+5

+2

+2

+5

+8

+2

+ 5

+ 13

+4

+2

Pet.

+2

+ 5

+ 5

+4

+ 1

0

+ 5

+5

+2

+2

+3

+ 3

+4

+5.7 +3.2

2

days

Pet.

+4

+8

+6

+ 5

+2

+ 1

+6

+9

+4

+3

+5

+2

+6

+ 4.7

3

days

1

day

Pet.

+6

+ 11

+8

+5

+2

+ 1

+5

+9

+3

+4

+ 18

+4

+ 4

Pet.

+ 2

+ 1

+4

+3

+ 1

-1

+ 3

0

+2

0

+2

0

-1

+6.2 + 1.2

2

days

Pet.

+2

+2

+4

+ 3

0

-1

+ 4

+2

+2

-1

+2

0

-2

+ 1.3

3

days

Pet.

+ 4

+3

+6

+3

+ 1

-1

+4

+ 1

+2

-2

+ 11

0

-5

+2.1

1 Results are of 2 tests on all the vegetables except onions.

TEMPERATURE CHANGES IN PRODUCE

REFRIGERATED AT NIGHT ONLY

Daytime Display^

Without

Refrigeration

Stored at Night in Rooms

with Temperatures of

32''and 40''F.

AO"" F. Room'

8 a.m. Noon 6 p.m. Midnight 8a.m.

*IV££/fLr TEMPERATURES OF THE DISPLAY-ROOM AIR RANGED FROM TA'* TO 77", AVERAGING 75"F.

à>.CURVES ARE BASED UPON THE AVERAGE HOURLY TEMPERATURES OF 9 DIFFERENT FRUITS AND VEGETABLES.

U. S. DEPARTMENT OF AGRICULTURE NEG. 3650-56(10) AGRICULTURAL MARKETfNG SERVICE

Figure 3.

11
TABLE 3.—Suitability of various temperatures for holding fresh fruits and

vegetables in retail stores ^

Cominodity

Apples

Apricots

Artichokes

Asparagus

Avocados, for

ripening.

Avocados, fullripe.

Bananas, for

ripening.

Bananas, full-ripe.,

Beans, snap

Beans, lima

Beets

Berries (strawberries, raspberries, blackberries).

Broccoli, sprouting.

Brussels sprouts. . .

Cabbage

Carrots

Cauliflower

Celery

Cherries

Collards

Corn, sweet

Cranberries

Cucumbers

Dates

Eggplant

Endive, escarole. . .

Figs, fresh

Grapefruit

Grapes

Kale

Leeks, green

Lemons

Lettuce

Limes

Mangoes

Melons, for

ripening.

Melons, full-ripe. . . Mushrooms

Nectarines, for

ripening.

Nectarines, fuUripe.

Okra

Onions, dry (see

text, page 25).

Onions, green

Oranges

Parsnips

Peaches, for

Best....

Best

Best....

Too low.

ripening.

See footnotes at end of table.

Produce temperatures—° F.

32° to 35°

Best 2.. .

Best

Best....

Best....

Too low.

Too low.

Too low.

Too low.

Too low.

Best....

Best....

Best....

Best

Best....

Best

Best

Best

Best

Best....

Best....

Best....

Too low.

Too low.

Best....

Too low.

Best

Best

Good. . .

Best....

Best....

Best....

Good. . .

Best....

Too low.

Too low.

Too low.

Too low.

Best

Too low.

Best....

Too low.

40° to 50°

Good

Good

Good

Fair to good

Too low.. . .

Best

Too low. . . .

Too low.. . .

45°-50° best

Good

Good

Fair to good

Good

Good

Good

Good

Good

Good

Fair to good

Good

Fair

Best

Best

Good

Best

Good

Fair to good

Good

Good

Good

Good

Best

Good

45°-50° best

Fair

Too low.. . .

Best

Fair

Too low.. ..

Good

Best

Fair

Good

Good

Too low....

55° to 60°

Fair

Fair

Fair

Fair

Good

Fair to good

Too low.. . .

Best

Good

Fair

Fair.

Fair

Too high. . .

Fair

Good

Fair

Fair

Fair

Fair

Fair

Too high. . . Good

Good

Good

Good

Fair

Fair

Good

Fair

Fair

Too high. . .

Good

Fair

Good

Best

Good

Fair to good

Too high. . .

Fair to good

Fair

Fair

Too high. . .

Good

Good

Fair to good.

65° to 75°

Too high.

Too high.

Too high.

Too high.

Best.

Too high.

Best.

Too high.

Fair.

Too high.

Too high.

Too high.

Too high.

Too high.

Fair.

Too high.

Too high.

Too high.

Too high.

Too high.

Too high.

Fair.

Fair to good.

Fair.

Too high.

Too high.

Too high.

Fair to.good.

Too high.

Too high.

Too high.

Fair.

Too high.

Fair.

Fair.

Fair.

Too high.

Too high.

Best.

Too high.

Too high.

Too high.

Fair to good.

Fair.

Best.

12
TABLE 3.—Suitability of various temperatures for holding freshß

vegetables in retail stores ^—Continued

ruits and

Commodity

Produce temperatures—° F.

32° to 35° 40° to 50° 55° to 60° 65° to 75°

Peaches, full-ripe. .

Peas, green.

Pears, for ripening.

Pears, full-ripe....

Peppers, green

Persimmons, for

Best. . Good

Fair to good. .

Too low

Good

Best

Fair Too high.

Too high.

60°-70^ best.

Too high.

Too high.

Best.

Best

Too low

Best

Too high

Good

Fair

Too low

Too low

Best

Fair

Fair Good

Fair

ripening.

Persimmons, fuU- Good

Too low

Best

Too high.

Good.

ripe.

Pineapples, for

ripening.

Pineapples, fullripe.

Plums (including

prunes), ripe.

Potatoes (see text

page 27).

Pumpkins and

winter squash.

Squash, summer

(soft-skin types).

Radishes

Too low

Good

Best

Fair

Fair Too high.

Too high.

Good.

Good

Too low

Best

Fair

Too low

Fair to good. .

Best

Best

Fair Too high.

Too high.

Too high.

Too high.

Too high.

Good.

Good

Good

Fair

Fair

Rhubarb Best Fair

Shallots Best Too high

Too high

Best

Spinach Best Fair to good. .

Too low

Good

Too low

Best

Sweetpotatoes

Tangerines

Tomatoes, for

ripening.

Tomatoes, fullToo low

Best Fair Too high.

60°-70^ best.

Too high.

Too high.

Good.

Too low

Good

Best

Fair to good..

Fair

ripe.

Turnips Good

Good

Good

Rutabagas Best Good

1 Recommendations are for produce displayed on racks in retail stores a maximum

of about 4 days and for storage of reserve stocks for less than 1 week. For details on

each item, see pages 14-30.

2 Explanation of terms used:

Best, most desirable temperatures.

Good, satisfactory temperatures for 3 or 4 days' display.

Fair, satisfactory temperatures for 1 or 2 days' display.

Too low, produce subject to chilling injury.

Too high, produce subject to rapid aging and decay.

modity will lose moisture to the surrounding air. Sprinkling the produce

with water or garnishing it with ice reduces this moisture loss and usually

aids in prolonging the attractiveness of produce (table 4).

The relative humidity of the air in the display room determines how

often sprinkling is needed. In dry climates, more frequent sprinkling

may be necessary than in areas where the humidity is high. When temperatures are high, decay develops rapidly if there is too much moisture;

sprinkling under such conditions should be held to a minimum. At low

temperatures sprinkling is not likely to be harmful, and the produce will

remain in good condition longer if the necessary moisture is supplied.

13
Produce displayed in the upper layers of display cases is much more

subject to moisture loss and wilting than that in the lower layers. Light

sprinkling of the upper layers of produce is effective in minimizing wilting.

Heavy wetting throughout the produce may cause waterlogging of some

kiiiJs of produce, especially when displayed without refrigeration during

the daytime. Matting of watersoaked leaves of such commodities as

bunched beets, bulk spinach, and other leafy vegetables may lead to decay.

In a large number of tests with 10 different vegetables in refrigerated

and in nonrefrigerated cases, the average temperature difference between

the sprinkled and nonsprinkled produce was less than one-half degree.

Temperature Requirements

Temperature requirements vary with different fruits and vegetables.

Some commodities keep best at room temperatures (65° to 75° F.). For

long storage periods most commodities need temperatures as low as 31°

or 32°, although some are injured at temperatures below 45° or 55°.

TABLE 4.—Attractiveness of produce as affected by sprinkling with water,

garnishing with ice, and not sprinkling or garnishing ^

Percentage of lots attractive at end of 1, 2, and 3 days

1st day 2d day 3d day

Display and storage 1

P

CO <^

11

1Ü2

CO ^

Ú 1

CO __>;^

c '«3

Is .5

Is

0

ICD

ai

0 Is

a

CD

at

0

Per- Per- Per- Per- Per- Per- Per- Per- Percent cent cent cent cent cent cent cent cent

On nonrefrigerated rack during

daytime:

In 32° F. room at night. 100 100 76 94 47 65

In 40° F. room at night. 90 97 83 83 41 55

In mechanically refrigerated.

open convection-type case: ^

On regular rack

On false bottom

97 97 76 93 59 76

91 91 73 73 41 32

In ice-bed case continuously 3. 4 100 100 100 495 96 97 4 86 88 83

1 Produce included: snap beans, bunched beets, broccoli, cabbage, bunched carrots,

cauliflower, cucumbers, lettuce, green onions, and bunched radishes.

2 Produce covered at night with heavy paper or canvas.

3 Produce covered at night with thick layer of ice over which heavy paper or canvas

was placed.

* Produce was not garnished with ice or sprinkled with water during the day but was

wet each morning from the ice used at night.

Differences in the inherent keeping quality of fruits and vegetables,

while not always apparent, may result in considerable variation in the

14
Lettuce

Peas

Cucumbers

Carrots

Celery

Cabbage

Burlap

Crushed ice

Slatted rack

resting on

Water 2X4's

drain

Figure 4.—The produce barrel packed with alternate layers of vegetables and crushed

ice for night storage.

time produce will remain in good condition at any given temperature.

Recommendations given in table 3 and elsewhere in this handbook apply

to produce that appears to be in reasonably good condition. Frequent

inspections should be made during the day to observe changes in quality

before material losses occur. Produce showing early signs of deterioration

should be given temporary temperature preference over similar sound

commodities. However, it should be quickly sold—at a reduced price,

if necessary.

Detailed descriptions of temperature and moisture requirements for

a number of fresh fruits and vegetables displayed in retail stores are given

in the following pages. They apply to produce in reasonably good

condition that may be displayed about 4 days or less on racks in retail

stores, or stored as reserve supplies for about 1 week.

Apples

Apples of good quality and condition may be displayed for several days

on nonrefrigerated racks. Refiigerated apples, however, retain a bright,

attractive appearance and crisp texture longer than nonrefrigerated

apples. Without refrigeration, apples age more rapidly, feel oily to

the touch, and soon develop a mealy texture. Apples in an advanced

stage of ripeness deteriorate rapidly and may soon become worthless if

not refrigerated or sold. The principal factors of deterioration that

may be retarded by refrigeration are softening of the flesh, internal breakdown, discoloration of bruises, and decay.

15
Reserve supplies of apples may be held satisfactorily for short periods

at temperatures of 32° to 50° F., the lower temperature giving the best

results.

Apricots

Apricots are highly perishable and should be moved quickly into consumer channels. They will keep well for a few days at temperatures of

32° to 50° F. in a relative humidity of 85 to 90 percent.

Artichokes

The true artichoke, a member of the thistle family, is known to the

trade as the globe artichoke. The edible bud, made up of a cone of

short, thick-stemmed leaves, is seldom stored. For temporary holding,

a temperature of about 32° F. is preferable, with a relative humidity of

90 to 95 percent to prevent drying and wilting. However, artichokes

should keep satisfactorily for several days at display temperatures of

40° to 50°. Artichokes often show brown discoloration of the outer

leaves, which may be caused by bruises or by freezing. At cool temperatures, artichokes may be lightly sprinkled to minimize wilting and

drying, but at warm temperatures, sprinkling with water encourages the

development of decay where water settles between the leaves.

Asparagus

Fresh asparagus deteriorates rapidly at temperatures above 32° F. In

retail stores, it should be displayed at temperatures as low as 32° if

available equipment permits. The original tenderness of fresh asparagus,

which at ordinary room temperatures is lost soon after cutting owing to

the formation of woody tissue, is preserved at low temperatures. Furthermore, after the asparagus is cut, the sugar content, which contributes

to the flavor, rapidly diminishes at temperatures above 32°; if the produce

is put in storage at 32° F. immediately after cutting, the sugar content

remains practically unchanged. Therefore, the sooner asparagus is placed

in proper storage after harvesting the better its condition will be when

used. Asparagus is likely to lose a great deal of water in storage or in

transit if the stalks are not stood on wet moss or other moist absorbent

material. Garnishing asparagus with ice or sprinkling it with water on

refrigerated display racks will preserve the quality longer.

Avocados

Aging and softening of ripe avocados can be retarded by holding at a

temperature of about 45° F., but they should not be displayed for more

than a few hours at tempérantures below 45°. At lower temperatures,

avocados are subject to cold, injury in the form of brown to black discolored flesh. A relative humidity of 85 to 90 percent is desirable.

Avocados are usually displayed without refrigeration for short periods.

16
Bananas

Green bananas ripen at temperatures of 62° to 70° F. and in a relative

humidity of 85 to 90 percent. After ripening, aging and softening of

fruits will be delayed if the bananas are held at temperatures of 56° to

60°. At temperatures below 56° bananas will become chilled and the

peel injured. Both green and ripe bananas are susceptible to chilling.

Fruit chilled in the green stage develops a dull smoky color. Fruit chilled

after ripening develops a dull-brown color when later exposed to higher

temperatures and is very susceptible to handling marks; the slightest

bruising causes discoloration of both peel and flesh. Prolonged exposure

to high temperatures results in poor color and hastens decay. Ripe

bananas are extremely perishable.

Beans, Lima

Unshelled lima beans can be expected to keep in good condition for

several days at temperatures of 32° to 45° F. Shelled lima beans are

much more perishable than the unshelled and will deteriorate rapidly at

room temperatures. The shelled beans should be held at as low temperatures as practical to control stickiness, spotting, and loss of sweetness,

succulence, and vitamin content. Unless the shelled beans can be refrigerated at 32° to 40°, they should be quickly moved into consumer channels. Studies by Brooks and McCoUoch ^ showed that high humidity

favors the development of stickiness and spotting. On the other hand,

too low humidity may result in severe shriveling. It is not advisable to

sprinkle shelled lima beans, especially at high temperatures, but the

unshelled beans may be lightly sprinkled with water.

Beans, Snap

Snap beans do not require as low temperatures as many other commodities; they may be displayed satisfactorily for a few days at temperatures

of 45° to 55° F. The beans are subject to russeting and some pitting

when held continuously below 45° for several days. Snap beans that

have been stored 3 to 5 days at 32° to 40°, and are then removed, will

usually develop pitting and russeting in about 1 day during warm weather.

However, if displayed on nonrefrigerated racks during the daytime, night

storage in 40° to 45° coolers with a relative humidity of 85 to 90 percent

will give satisfactory results for 2 or 3 days. Sprinkling snap beans

with water or garnishing them with crushed ice will prolong their shelf

life by preventing moisture losses that cause drying and flabbiness.

Beets

Bunched beets, especially the tops, are highly perishable. Since low

temperatures help retard the development of decay of the tender, leafy

« Brooks, Chas., and McCoUoch, L. P. Stickiness and Spotting of Shelled Green

Lima Beans. U. S. Dept. Agr. Tech. Bui. No. 625, July 1938.

17
tops, beets should be kept as cool as possible. Display temperatures of

50° F. or lower are desirable, and even temperatures as low as 32° will

not injure beets but will prolong their shelf life. Bunched beets that

have been displayed during the daytime on nonrefrigerated racks should

be stored under refrigeration at night.

Sprinkling with water or garnishing with crushed ice aids in preventing

sponginess of the roots and wilting of the leaves. Beets in the upper

layers in the display are usually the first to become wilted and spongy,

while those in the lower layers generally remain crisp and firm. Light

sprinkling is advisable when beets are displayed at low temperatures, but

little sprinkling of the leaves should be done at high temperatures, especially if the air is very humid. Heavy sprinkling may cause the leaves

to become matted, and, when temperatures are high, decay develops

quickly if there is too much water. Only enough water to keep the

beets moist in the upper layers should be applied. If these are sufficiently moist, those in the lower layers will be also. The tops should be

loosened occasionally to prevent matting of wet leaves.

Reserve supplies of both bunched and topped beets may be held at

temperatures of 32° to 45° F. in a relative humidity of 80 to 90 percent.

Crushed ice spread over the beets provides both low temperature and

desirable moisture conditions.

Berries

Berries such as strawberries, raspberries, blackberries, dewberries, blueberries, and huckleberries are highly perishable and should be offered for

sale as quickly as possible. In refrigerated cases, they may be displayed

satisfactorily at temperatures of 32° to 50° F. but will keep better at temperatures below 40°. If daytime refrigeration is not available and it is

necessary to keep berries another day, they should be held at night in a

room the temperature of which is 32° to 40° and the relative humidity

85 to 90 percent.

Berries should not be sprinkled.

Broccoli (Italian or sprouting)

Italian or sprouting broccoli is highly perishable and while it may be

displayed for 2 or 3 days at temperatures of 40° to 50° F., temperatures

of 32° to 35° are even better. At temperatures above 55°, broccoli ages

rapidly, the buds turn yellow or brown, and early stages of decay soon

appear. Without refrigeration, only 1 day's shelf life can be expected

because of wilting and yellowing. If daytime refrigeration is not

available, refrigeration at night should be furnished.

Broccoli should be garnished with ice or, at low temperatures, sprinkled

with water to minimize wilting, yellowing, or other discoloration, and

weight losses. Light sprinkling is more desirable than heavy wetting,

especially at high temperatures when excessively wet produce is more

18
likely to decay. If the broccoli is not refrigerated during the day or night,

sprinkling is not recommended because of the danger of decay, with consequent off-odors.

Reserve supplies keep best if covered with crushed ice, but some deterioration may occur under any method of storage. A relative humidity of

90 to 95 percent is desirable.

Brussels sprouts

Brussels sprouts are highly perishable and should be sold quickly.

Temperatures as low as 32° F. and high humidity (90 to 95 percent) are

desirable. Low temperatures retard the development of yellow leaves

and decay. Brussels sprouts, need not be sprinkled with water unless

wilting appears, and then only at low temperatures.

Cabbage

Refrigeration in retail stores is desirable if display space is available.

Sprinkling with water aids in preventing wilting and drying of the outer

leaves and results in a more attractive appearance of the heads.

Reserve supplies of cabbage keep best when refrigerated; temperatures

of 50° F. or lower and a relative humidity of 90 to 95 percent are beneficial.

Carrots

Carrots have a longer shelf life if prepackaged than if displayed in

bulk, because the highly peiishable tops have been removed and the roots

are protected in moisture-retentive bags. Bunched carrots are still displayed in some stores, especially duiing the marketing of locally grown

stock. Both prepackaged and bulk carrots need refrigeration for best

results. The latter may require lower temperatures to minimize decay

and yellowing or other discoloration of the leaves.

Variation in the condition in which bunched carrots are received at the

retail store may cause wide differences in results obtained on the display

racks. The principal defects are yellow and discolored (brownish) leaves

and flabby, discolored, and shriveled roots. These defects develop rapidly

in cairots that are not sprinkled and are held at high temperatures.

Sprinkling with water at low temperatures prolongs the shelf life by preserving a fresh appearance of the leaves and firmness of the roots. Light

sprinkling will give better results than heavy wetting, which may cause

dark, watersoaked areas on the leaves. If daytime refrigeration is not

available, night refrigeration should be furnished. When carrots are displayed in an ice-bed case, garnishing with ice or lightly sprinkling with

water several times daily will prolong their shelf life.

Reserve supplies of carrots will keep for several days at temperatures

of 32° to 50° F. A relative humidity of 90 to 95 percent is desirable for

bunched carrots. Crushed ice spread over bunched carrots reduces the

temperature and provides satisfactory moisture conditions.

19
Cauliflower

The principal defects of cauliflower that may develop in the retail

store are spotted discoloration and flabhiness of the curds and wilting

and yellowing of the leaves. Spreading and loose formation of the curds

indicate aging, which may be slowed down by low temperatures and high

humidity.

Cauliflower should be kept as cool as possible; temperatures as low as

32*^ F. are desirable. Cauliflower in good condition may be displayed

satisfactorily for 2 or 3 days at temperatures of 32° to 50°. Sprinkling

with water or garnishing with crushed ice reduces weight losses and

lessens wilting of the leaves and flabhiness of the curds. When the

average temperature of the cauliflower is above 50°, however, sprinkling

sometimes results in spotting of the curds. Cauliflower that has been

displayed on nonrefrigerated racks during the day should be refrigerated

at night.

Reserve supplies should be stored at 32° to 40° F. and at a humidity of

85 to 90 percent.

Celery

Display temperatures of 50° F. or lower and sprinkling with water

several times daily will keep celery in good condition for several days.

Celery displayed without refrigeration during the day should be refrigerated at night.

Reserve supplies of celery should be stored at about 32° to 35° F. if

possible. Crushed ice spread over the celery will provide desirable low

temperatures and ideal moisture conditions. A relative humidity of

90 to 95 percent is desirable.

Cherries

Cherries are highly perishable and benefit from display temperatures

of 40° to 50° F. If cherries are held too long after removal from storage—

especially if they are wet from sweating—brown rot and gray, blue, or

green mold rots may develop. Cherries should not be sprinkled.

Reserve stocks may be held for a few days at low temperature, preferably 32° F., at a relative humidity of 85 to 90 percent.

CoUards

Collards can be expected to keep in satisfactory condition for a few

days at temperatures as high as 50° F. If displayed without refrigeration

during the day, they should be sprinkled with water or garnished with ice

during the day and refrigerated at night. Crushed ice spread over reserve

supplies will keep them cool and provide beneficial moisture. A relative

humidity of 90 to 95 percent is desirable.

20
Corn, Sweet

Sugar content largely determines the quality of sweet corn. It decreases rapidly at ordinary room temperatures but decreases more slowly

at a temperature of 32° F. Sweet corn heats rapidly imless it is well

refrigerated; it should be kept at the lowest possible temperature above

freezing. If sweet corn is not sold during the first day on display, it

should be refrigerated at night. A light layer of crushed ice spread over

the corn during the day and a heavy layer at night will help to reduce the

temperature and provide desirable moisture.

Cranberries

During cool seasons, cranberries may be displayed without refrigeration

for several days, but temperatures of 36° to 50° F. are always beneficial.

Temperatures below 36° are harmful. If cranberries are held below 36°

for over 2 or 3 weeks, "low-temperature breakdown," marked by a

rubbery texture, develops.

Cucumbers

Cucumbers should be displayed at temperatures at 40° to 50° F. If

they are held more than a few days at temperatures below 40°, surface

pitting or dark, watery areas appear. Such areas soon become infected,

and the affected cucumbers decay rapidly on removal to warmer temperatures. Sprinkling with water has no material advantage but is not

harmful.

Reserve supplies should be held at about 45° F. and a relative humidity

of 85 to 95 percent.

Dates

Dates ordinarily stand up fairly well for several days at room temperatures. However, the lower the temperature below 50° F. the better their

keeping quality. Temperatures as low as zero do not harm dates but

are actually beneficial to them. Dates readily absorb moisture and odors

from the air. The rate of absorption is much less at temperatures below

32° than at those above 32°. Deterioration caused by humidity above

75 percent is slow at temperatures below 28°. If dates gain excessive

moisture they become more perishable, and if they lose excessive moisture

they become too dry for consumer acceptance.

Eggplant

The best conditions for eggplant are temperatures between 40° and

50° F. and a relative humidity of 85 to 90 percent. Surface pitting and

bronzing frequently occur on eggplants held continuously at temperatures

below 40°. Unsightly indentations and a fading of the purple color may

result from direct contact with ice. Eggplants lose moisture and become

soft and wrinkled if displayed continuously for several days without

21
refrigeration. When daytime refrigeration is not available, egg plants

should be stored overnight at temperatures of about 40° to 45°. Sprinkling with water is beneficial.

Endive

Curly endive and broad-leaved escarole, like lettuce, should be well

refrigerated to prevent heating and to retard the development of decay.

Temperatures of 32° to 35° F. are most desirable, but temperatures of 40°

to 50° will prove beneficial for several days. At these temperatures,

light sprinkling with water will minimize wilting and give the produce an

attiactive appearance. When enaive is stored overnight in a refrigerated

room, a relative humidity of 90 to 95 percent is desirable.

Figs, Fresh

The best temperature for fresh figs is 32° F. Temperatures up to 45°

are reasonably satisfactory for a few days. Alternaria spotting, which

may start while figs are on the trees and may continue to develop after

harvest especially around 50°, greatly detracts from the appearance of the

fruit. Reserve stocks should be kept to a minimum. Best holding

conditions are 31° to 32° and a relative humidity of 85 to 90 percent.

Grapefruit

Grapefruit in good condition may be displayed for 4 or 5 days at room

temperatures without significant loss of quality. For short storage

periods, grapefruit can be held satisfactorily at temperatures ranging

from 32° to 60° F. and a relative humidity of 85 to 90 percent. Sprinkling

with water gives no material advantage but is not harmful during short

display periods.

Grapes

The European, or vinifera, grapes are benefited by temperatures between 30° and 50° F., and a relative humidity of 85 to 90 percent. Low

humidity results in shriveling, especially of the stems. Although the

stems may become dry, and sometimes may become brittle when held or

displayed in a dry atmosphere, the risk of increasing mold and decay is

too great to justify sprinkling with water.

Reserve supplies may be held satisfactorily for a few days at 30° to

40° F.

Kale

Both prepackaged and bulk kale should be refrigerated. Display

temperatures of 40° to 50° F. will give reasonably good results, but

temperatures below this range to a minimum of 32°, are preferable.

Bulk kale should be lightly sprinkled with water or garnished with ice to

preserve freshness. Reserve supplies are best held at temperatures of

32° to 40° and a relative humidity of 90 to 95 percent.

22
Leeks, Green

Green leeks are best held at 32° to 40° F., but they may be displayed

for about 2 days at 40° to 50°. Sprinkling with water at low temperatures

or garnishing with crushed ice aids in the prevention of wilting and drying, but at high temperatures the application of water may result in the

development of slimy decay.

Reserve stocks keep best under a covering of crushed ice in a refrigerated

storage room. A relative humidity of 90 to 95 percent is desirable.

Lemons

Lemons will retain a fresh, attractive appearance for about 10 days at

temperatures of 32° to 50° F. Overnight storage at 32° to 50° is recommended. Reserve supplies to be held under constant conditions longer

than 10 days or so are best kept at temperatures of 50° to 55°. If lemons

are displayed continuously at room temperatures for a week or more,

frequently they become excessively soft or their skins become dry and

ridged. As the loss of moisture continues the fruit may also shrink in

size.

Sprinkling with water several times daily has no harmful effect, and it

often aids in preventing shriveling and weight losses, even in lemons

displayed at room temperatures.

Lettuce

Lettuce will decay rapidly unless well refrigerated. Temperatures of

32° to 35° F. are most desirable, but even those of 40° to 50° will retard

the development of decay for 2 or 3 days. If displayed in a mechanically

refrigerated case, or if held overnight in a cold room after daytime display without refrigeration, lettuce should be lightly sprinkled several

times daily to prevent wilting or withering. If displayed in an ice-bed

case, it should be garnished with ice or sprinkled with water several times

during the day and covered with a heavy layer of ice when prepared for

night storage. Lettuce displayed on a nonrefrigerated rack should be

held at low temperatures at night. Sprinkling of nonrefrigerated lettuce

should be kept to a minimum.

Wrapping individual heads of lettuce in film not only aids in the retention of moisture but also prevents loss of outer leaves caused by frequent

customer handling.

Limes, Tahiti (Persian)

Limes are subject to pitting when held at temperatures below 45° F.

The best display temperatures are between 45° and 50°. Holding for a

few hours at temperatures between 45° and 40° will cause no harm. The

fruit gradually yellows at room temperatures. Sprinkling with tapwater

is not harmful and is sometimes beneficial. In storage, a relative humidity

of 85 to 90 percent is desirable.

23
Mangoes

Mangoes may be stored satisfactorily at temperatures of 55° to 75° F.

Internal discoloration of the flesh may develop in storage at temperatures

below 55°, but temperatures of about 45° to 50° will retard decay and

softening of full-ripe fruit.

Melons

Cantaloups, honeydew. Casaba, Crenshaw, and Persian melons usually

need no refrigeration while on display in retail stores. If full ripe, however, they are held best at temperatures of about 45° F. Surplus unripe

melons are best held at 55° or higher; otherwise they may fail to ripen

satisfactorily. If melons are stored too long or at too low temperatures,

breakdown or decay develops so rapidly on removal to room temperatures

that they soon become worthless. Important defects are softening of

bruised areas, decay, surface breakdown, and off-flavors.

Except for convenience to the customer, watermelons need no refrigeration during display in retail stores. They may be held in storage for 2

or 3 weeks at temperatures of 36° to 40° F. and a relative humidity of 85

to 90 percent. At 32°, decay will not develop so rapidly but after 1

week the watermelons may become pitted or dented and take on an

objectionable flavor.

Mushrooms, Cultivated

Mushrooms should be displayed under refrigeration, for best results.

Freshly picked mushrooms will keep in prime condition for 3 to 5 days

at 32° F., for 1 or 2 days at 40°, and for only 1 day at 50°.

Nectarines

Unripe nectarines are best displayed without refrigeration. Ripe

nectarines' however, should either be displayed continuously in refrigerated cases or be stored in refrigerated fruit and vegetable storage rooms

at night after daytime display without refrigeration. Reserve supplies

of nectarines may be held satisfactorily for several days at temperatures

of 32° to 45° F. and a relative humidity of 85 to 90 percent. The lower

the holding temperature, the longer the nectarines may be displayed in

retail stores.

Okra

Okra does best at temperatures of about 50° F. At temperatures

below 40° it may show surface discoloration, pitting, and decay after

removal to room temperatures. In 3 days, at 70° some of the pods will

be decayed or shriveled, but at 32° nearly all the pods will be severely

pitted. Contact or top ice has caused waterlogging in 3 days at all

temperatures. Sprinkling is not generally advisable, but a relative

humidity of 85 to 95 percent in storage will minimize wilting.

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Onions, Dry

Dry or cured onions need not be refrigerated during short display or

storage periods. They should be kept dry, because high humidity induces

root growth and decay. A humidity of 70 to 75 percent is desirable.

Reserve supplies of dry onions should not be refrigerated in retail

stores, as dampness from sweating on removal to room temperatures

will encourage mold growth. Since sprouting is a problem at high temperatures, excessive supplies should be avoided.

Onions, Green

Green onions and green shallots are highly perishable, even when displayed in refrigerated cases, and should be marketed as quickly as possible. High temperatures accelerate and low temperatures retard the

development of yellow and decayed leaves. Green onions and shallots

should be kept at temperatures as low as 32° F., if available equipment

permits, during both day and night. Onions and shallots that have

been displayed during the daytime on nonrefrigerated racks should be

refrigerated at night. At high temperatures, sprinkling with water minimizes wilting but may result in more slimy decay than in onions not

sprinkled. As decay is much more serious than wilting, sprinkling at

high temperatures should be held to a minimum or eliminated entirely.

Sprinkling at low temperatures preserves a fresh, crisp, attractive appearance. Crushed ice spread over the onions and shallots during display

and in storage will aid in keeping them cool and supply moisture to lessen

wilting.

Oranges

Oranges received in good condition at the retail store may be held for

4 or 5 days at room temperatures without material deterioration. However, refrigeration is always beneficial. Oranges that show signs of

withering or decay should be held under refrigeration at low temperatures

or quickly marketed; if daytime refrigeration is not available, the oranges

should be removed to cold rooms at night. Moisture from condensation

or sprinkling with tapwater may slightly reduce moisture loss and will

have no harmful effect upon the condition of the fruit. ^

Reserve supplies should be held at temperatures between 32° and 50° F.

in a relative humidity of 85 to 90 percent.

Parsnips

Parsnips may be displayed for a few days without refrigeration, but

temperatures below 50° F., together with sprinkling with water, are

beneficial. Reserve supplies of parsnips may be held at temperatures of

32° to about 45°. A relative humidity of 90 to 95 percent in the storage

room is desirable to minimize wilting.

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Peaches

As refrigeration retards ripening, peaches that have not yet ripened

sufficiently should be displayed without refrigeration. On the other

hand, to keep ripe peaches in the best condition, they should either be

displayed in a refrigerated case or stored in a fruit and vegetable storage

room at night after daytime display in nonrefrigerated cases. Weight

losses and losses from decay are greatest in peaches displayed without

refrigeration. Tests have shown that moisture condensation caused by

changes in temperature from refrigerated storage to room temperature

displays had no harmful effect.

Reserve supplies of peaches may be held satisfactorily for a few days

at temperatures of 32° to 45° F. and in a relative humidity of 85 to 90

percent.

Pears

The best ripening temperature for pears is about 60° to 70° F.; they

usually do not soften but will soon decay at tempeiatures as high as 75°

to 80°. Pears that have been conditioned (that is, brought to a stage

so they will be ripe enough to eat in a day or so) may be displayed to

advantage at temperatures of 40° to 50°.

Reserve supplies of conditioned pears should be held at temperatures

of about 40° to 45° F. in a relative humidity of 90 to 95 percent.

Sprinkling with water is not advisable because it sometimes results in

watersoaking of the flesh at skinbreaks. Physical handling of pears

should be kept to a minimum, and excessive handling discouraged.

Moving pears from display racks to and from refrigerated night storage

rooms often results in scratches and bruises that become badly discolored

when the pears are displayed at room temperatures.

Peas, Green

Green peas are highly perishable and should be sold quickly if desirable

quality is to be offered and excessive losses avoided. Refrigerated peas

are more attractive and taste better than nonrefrigerated peas. Unless

held at 32° F., part of their sugar content is lost. Green peas lose quality

rapidly at temperatures above 45°. At low temperatures, light sprinkling

with water or garnishing with crushed ice will delay excessive withering

or drying of the pods. Peas displayed without refrigeration during the

daytime should be refrigerated at night. When held overnight in cold

rooms, the spreading of ice over the peas is beneficial. Shelled peas are

even more perishable than the unshelled.

Peppers, Green

Green peppers are subject to chilling injury when held continuously at

temperatures below 45° F. The surface of the peppers may become

pitted and the calyx discolored after removal to higher temperatures.

26
However, temperatures of 40° to 50° are satisfactory for peppers for the

short period they are held in retail stores. At these temperatures,

peppers may be lightly sprinkled with water to prevent wilting and loss

of weight. At high temperatures, sprinkling increases decay; without

sprinkling, peppers lose weight and become flabby. Red color develops

rather rapidly at temperatures above 50°.

Reserve supplies may be held for a few days at 40° to 50° F. with a

relative humidity of 85 to 90 percent.

"Weak" peppers, even under the best handling practices, may show

excessive deterioration after only a short display period. Because of the

difficulty of recognizing weak peppers, especially without knowledge of

the previous history of growing, handling, transportation, storage, and

other conditions, retailers should market peppers as soon as possible to

minimize losses.

Persimmons

Persimmons will ripen in a few days at a temperature of 55° F. or higher.

The best temperatures to delay ripening or to hold ripe persimmons are

about 30° to 32°. A relative humidity of 85 to 90 percent is desirable.

Pineapples

Full-ripe pineapples can be held satisfactorily at 40° to 45° F.; maturegreen fruits should not be displayed at temperatures below 50°, as some

of these retain part of the green color in the skin and fail to develop

good flavor in the flesh after removal to room temperatures. The

relative humidity for pineapples should be about 85 to 90 percent.

Plums (including prunes)

Display temperatures of 40° to 50° F. are beneficial, but plums and

fresh prunes may be displayed at higher temperatures for a day or so.

Decay, shriveling, and internal browning are the main condition defects

of plums and prunes.

Reserve supplies are benefited by temperatures as low as 31° F. in a

relative humidity of 85 to 90 percent.

Potatoes

Potatoes can be displayed and reserve supplies satisfactorily stored

without refrigeration in retail stores. They should not be displayed in

bright sunlight; even display-case or other store lighting may cause

greening of the potatoes after exposure for several days. Reserve stocks

of early-crop potatoes can be held at 50° F. if space is available. Earlycrop potatoes are more perishable than late crop.

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Pumpkins and Squashes

Pumpkins and hard-shell squashes can be displayed and reserve

supplies held satisfactorily without refrigeration. Temperatures below

50° F. may cause cold injury that is often followed by decay.

Summer squash—yellow crookneck, straight (^^banana"), and other

soft-skin types—^may be displayed at temperatures of 35° to 50° F.

Sprinkling with water minimizes drying and reduces weight losses.

Reserve supplies may be held satisfactorily at temperatures of 35° to

45° in a humidity of 90 to 95 percent.

Yellow summer squash often becomes badly discolored from frequent

handling. Extreme care and minimum handling will lessen unsightly

discoloration of yellow summer squash displayed in retail stores.

Radishes

Radish roots are commonly prepackaged in film bags. Removal of

the leafy tops reduces decay, and the film bag aids in the retention of

moisture in the roots. Radishes with tops are still found in some retail

stores, especially during the marketing of locally grown stock. Both

prepackaged and bulk radishes should be refrigerated to preserve satisfactory quality.

Bunched radishes, one of the most highly perishable commodities

displayed in retail stores, should be quickly sold. Temperatures of 32°

to 35° F. are most desirable, but display at 45° to 50° for a day or so will

retard the development of decay and yellowing of the leaves. At temperatures above 50°, decay progresses more or less rapidly, depending

upon the condition of the radishes when received at the store. Decay

often starts where the tissue has been injured by tie-strings. Radishes

that have been displayed during the daytime on nonrefrigerated racks

should be refrigerated at night. Garnishing bunched radishes with

crushed ice prolongs their shelf life by providing moisture as well as

lowering temperatures. Radishes may be sprinkled lightly to lessen

yellowing and wilting of the leaves and flabbiness of the roots.

Reserve supplies of bunched radishes keep best at 32° to 40° F. with

a relative humidity of 90 to 95 percent. Crushed ice spread over the

radishes during storage will provide desirable moisture and low temperatures.

Raspberries

See Berries.

Rhubarb

Temperatures of 32° to 50° F. and a relative humidity of 90 to 95

percent are beneficial to rhubarb. If space is available, rhubarb should

be displayed in an ice-bed case or on mechanically refrigerated racks and

garnished with ice or sprinkeld with water to prevent heating and drying.

Rhubarb displayed without refrigeration during the daytime should be

refrigerated at night.

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Reserve supplies should be stored at temperatures of 32° to 40*^ F.

Rhubarb should be loosely packed to allow good circulation of air;

mold

Shallots

See Onions, Green.

Spinach

Prepackaged and bulk spinach should be kept as cool as available

refrigeration will permit witliout freezing. Temperatures as low as

most

will usually keep satisfactorily for 1 or 2 days at temperatures as high as

50°. A relative humidity of 90 to 95 percent is desirable.

At low temperatures, sprinkUng with water or garnishing with ice will

help keep bulk spinach crisp and fresh in appearance. At high temperatures, spinach will become wilted if not sprinkled or garnished, and yet,

if sprinkled, it is more likely to decay. Spinach should be arranged

loosely on display racks to allow good air circulation. If displayed without refrigeration during the daytime, spinach should be refrigerated at

night. Garnishing with crushed ice will aid in preserving crispness and

minimize yellowing and the development of decay. When iced produce

barrels are used, bulk spinach should be placed in cloth bags to facilitate

handling

Squashes

See Pumpkins and Squashes.

Strawberries

See Berries.

Sweetpotatoes

Sweetpotatoes should not be refrigerated in retail stores,

res below 55° F. should be avoided because of possible chilling injury

damage from certain types of decay, which may develop in the injured

Tempe

/'

fter removal to higher temperatures. Noncured

more susceptible to cold injury than cured The

symptoms of cold injury are increased decay, pitting, and internal

discoloration which may show up before or after cooking. Sweetpotatoes

should be handled as little and as carefully as possible to avoid skinbreaks,

through which decay organisms can enter and quickly cause decay.

Tangerines

4

Temperatures of 32° to 50° F. and high humidity are very beneficial

in maintaining the quality of tangerines. Low temperatures reduce

decay greatly and aid in the retention of the natural flavor. Sprinkling

with water several times daily minimizes drying. When daytime refrigeration is not available, tangerines should be stored at night in cold

rooms.

29
Reserve stocks of tangerines should be stored at 32° to 40° F. in a

relative humidity of 90 to 95 percent.

Tomatoes

The holding temperatures for tomatoes in retail stores depends on the

rate at which tomatoes aie sold, the stage of ripeness preferred by the

customers, and the stage of ripeness of the stock on hand. If the demand

is mostly for fully colored tomatoes and they are delivered at the store

below this stage of ripeness, a majority of the stock should be ripened

before they are offered for sale.

Mature-green tomatoes ripen best at temperatures of 60° to 70° F.

At temperatures below 55° tomatoes develop poor color when ripe, and

have a tendency to decay. At 55° they ripen slowly; at 70° they may

be ripened rather rapidly for immediate demand, but a temperature range

of 60° to 65° is preferable and is used most often by the tomato-ripening

industry. At this range, ripening is slower than at 70° or above, but the

fruit is firmer when ripe and there is usually less loss from decay. Displaying ripe tomatoes at 40° to 50° may delay aging and breakdown.

Reserve supplies of unripe tomatoes should be held at temperatures of

about 55° to 70° F.

Turnips and Rutabagas

Bunched turnips are not so perishable as bunched beets or bunched

carrots; the tops are less tender and the roots less subject to drying.

Temperatures of 32° to 50° F. will give satisfactory results for several

days, and sprinkling with water will aid in keeping the tops fresh, green,

and attractive, and the roots firm. Topped turnips may be displayed

without refrigeration for 2 or 3 days, but storage in coolers at night is

helpful in retaining good quality and condition.

Rutabagas are very hardy and are displayed without refrigeration in

retail stores. Sprinkling with water has no advantage as they are usually

coated with a heavy application of wax.

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U. S. GOVERNMENT PRINTING OFFICE : 1957 O—41720t