This document provides information on freezing foods for food preservation. It discusses the principles of freezing, types of freezers and packaging materials, how to freeze different foods like fruits, vegetables, meats and fish, shelf life of frozen foods, and what to do in freezer emergencies. The key steps outlined are preparing foods for freezing, blanching vegetables, using proper packaging and labels, freezing at 0°F or colder, and storing frozen foods for optimal quality and shelf life.
4. Principles of Freezing
Does not sterilize food.
Extreme cold (0oF or colder):
stops growth of microorganisms and
Slows chemical changes, such as enzymatic
reactions.
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5. Advantages of Freezing
Many foods can be frozen.
Natural color, flavor, and nutritive value
retained.
Texture usually better than other methods of
food preservation.
Foods can be frozen in less time than they can
be dried or canned.
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6. Advantages of Freezing
Simple procedures.
Adds convenience to food preparation.
Proportions can be adapted to needs unlike
other home preservation methods.
Kitchen remains cool and comfortable.
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7. Disadvantages of Freezing
Texture of some foods is undesirable because
of freezing process.
Initial investment and cost of maintaining
freezer is high.
Storage space limited by capacity of freezer.
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8. How Freezing Affects Food
Chemical changes
Enzymes in vegetables
Enzymes in fruit
Rancidity
Texture Changes
Expansion of food
Ice crystals
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10. Freezer Selection
Consider:
Size
Shape
Efficiency
Defrosting features
Available floor area
Amount of freezer space needed
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11. Freezer Selection
What size?
General Rule
Allow 6 cubic feet of freezer space per person (3 cubic
feet per person might be adequate if other methods of
food preservation are used).
Standard Freezer
Capacity -- 35 pounds of frozen food per cubic foot or
usable space.
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12. Types of Freezers
Upright
6 to 22 cubic feet
Convenient
Uses small floor space
Easy to load and unload
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13. Types of Freezers
Chest
6 to32 cubic feet
Takes more floor space
More economical to buy and to operate than upright
Loses less air when opened
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14. Types of Freezers
Refrigerator - Freezer Combination
2 to 6 cubic feet
Be sure can set temperature at 0ºF or colder
Freezer can be above, below, or beside refrigerator
area
Other features
Self defrosting or manual defrost
Receptacle clips - prevent accidental disconnecting
Door locks and drains for defrosting
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15. Location and Placement of
Freezer
Place in convenient, cool, dry, well-ventilated
area.
Do not place by stove, range, water heater or in
the sun.
Do not push flush against wall. Leave space for
air circulation and cleaning.
Be sure freezer is level.
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17. Packaging Materials
Moisture-vapor resistant
Durable and leak-proof
Not become brittle and crack at low temperatures.
Resistant to oil, grease, or water
Protects foods from absorption of off-flavors or odors
Easy to seal and mark
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18. Types of Packaging Materials
Rigid Containers
Plastic freezer containers
Freezer boxes with liners
Coffee canisters
Wide mouth canning/freezing jars
Good for liquids, soft, juicy, or liquid-
packed foods
May be reusable
Hold their shape and can be stored upright
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19. Types of Packaging Materials
Non-Rigid Containers
Bags
Wrappings - cellophane, heavy-duty aluminum foil,
polyethylene, laminated paper
Good for firm, non-juicy foods
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21. General Freezing Instructions
Selection
Freezing does not improve quality.
Choose the highest quality available.
Freeze promptly.
Remember some foods do not freeze well.
Preparation
Work under sanitary conditions.
Follow recommended procedures.
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22. Packing Foods to be Frozen
Cool food before freezing.
Ice bath
Pack in serving size quantities.
Usually up to 1 quart
Pack foods tightly.
Allow for some headspace.
Vegetables like broccoli and asparagus, bony
pieces of meat, tray packed foods, and breads,
do not need any headspace.
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23. Packing Foods to be Frozen
Press all air from bagged foods, seal bags by
twisting and then folding over loose edge
(gooseneck). Secure with string, twist-tie or
rubber band.
Use tight lid on rigid containers and keep
sealing edge clean. Use freezer tape on loose
fitting covers.
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24. Washing Fruits and Vegetables
Wash fruits and vegetables in warm water
before freezer.
The only exception to this rule is that
blueberries should not be washed before
freezing.
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25. Labels
Name of product
Added ingredients
Form of food: halves, whole, or ground
Packing date
Number of servings or amount
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26. Freezing
Freeze foods at <0ºF (set freezer at -10ºF at
least 24 hours before freezing foods).
Freeze foods immediately.
Do not overload freezer with unfrozen food.
Freeze amount that will freeze in 24 hours -- 2
to 3 pounds of food per cubic foot.
Pack already frozen foods together so they do
not thaw.
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27. Freezing
Place unfrozen foods in contact with surfaces and in
coldest parts of freezer.
Leave space so air can circulate.
When food is frozen, organize freezer into types of
food.
Arrange frozen foods so that the foods frozen
longer can be used first.
Keep a current frozen foods inventory.
Check freezer temperature periodically.
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28. Sweetened Packs for Fruit
Syrup Pack
Better texture
Not needed for safety
Fruits should be covered with syrup
Place crumpled water-resistant paper in top of
container
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29. Sweetened Packs for Fruit
Sugar Pack
Soft sliced fruits (strawberries, peaches, etc.) make
on syrup when mixed with the right proportion of
sugar.
Layer fruit and sugar.
Allow it to stand for 15 minutes.
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30. Unsweetened Packs for Fruit
Dry Pack
Good for small whole fruits such as berries that
do not need sugar.
Simply pack into containers and freeze.
Can freeze on a tray first, so pour easily.
Pectin Syrup
Good for strawberries and peaches.
Mix 1 pkg. powdered pectin and 1 cup water.
Bring to boil, boil 1 minute. Remove from heat,
cool, and add 1-3/4 cups more water.
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31. Unsweetened Packs for Fruit
Water or Unsweetened Juice Packs
Texture will be mushier.
Color poorer.
Freezes harder, takes longer to thaw.
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32. Packs for Purees or Juices
Pack as is, with or without sugar.
Add ascorbic acid if light-colored.
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33. Artificial Sweeteners
Can be used in the pectin syrup, juice, or water
packs.
Or could be added just before serving
Do not help with color retention or texture, like
sugar does.
Use amounts on product labels.
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34. Preventing Fruit Darkening
The following work well:
1 teaspoon (3000 mg) ascorbic acid to one
gallon of water
Commercial ascorbic acid mixture
Heating the fruit
The following do not work as well:
Citric acid solution
Lemon juice
Sugar syrup
Salt/vinegar solution
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35. Preventing Discoloration during
Freezing
Ascorbic Acid
Is the most economical.
Use powdered or tablet form.
1/2 teaspoon powdered ascorbic acid = 1500 mg
Crush tablets well.
Use amount specified for each fruit.
In syrup or liquid packs, add powder to liquid.
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36. Preventing Discoloration during
Freezing
In sugar or dry packs, dissolve 2 to 3 tablespoons in
cold water and sprinkle over fruit.
For crushed fruit, purees or juices, mix with fruit
about 1/8 teaspoon per quart.
Ascorbic Acid Mixtures
Follow package directions
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37. Preventing Discoloration during
Freezing
Citric Acid or Lemon Juice
Not as effective
May mask flavors
Steaming
Best for fruits that will be cooked before use
Follow directions in freezing publications
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38. Freezing Vegetables
Select young, tender, high-quality vegetables.
Sort for size and ripeness.
Wash and drain before removing skins or shells.
Wash small lots at a time, lifting out of water.
Do not soak.
Work in small quantities, preparing per
instructions.
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39. Preventing Flavor and Color
Changes in Vegetables
Water blanching
Use 1 gallon water per pound of vegetables.
Place vegetables in blanching basket.
Lower into vigorously boiling water.
Cover and begin timing.
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40. Blanching Vegetables
Steam Blanching
Use kettle with tight lid and basket.
Put 1 to 2 inches of boiling water in the bottom of
pan.
Vegetables should be in a single layer in basket.
Start timing when covered.
Takes 1-1/2 times longer than water blanching.
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41. Blanching Vegetables
Microwave Blanching (not recommended)
Enzymes might not be inactivated.
Does not save time or energy.
Use specific directions and blanch small quantities
at a time.
After blanching, cool immediately in cold water.
Change water frequently.
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42. Types of Pack for Vegetables
Dry Pack
Pack after blanched, cooled, and drained.
Pack quickly, excluding air.
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43. Types of Pack for Vegetables
Tray Pack
After draining, spread in a single layer on a shallow
pan.
Freeze firm.
After first hour, check often.
Pack quickly, excluding air.
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44. Freezing Meats and Poultry
Keep meat or poultry and everything they touch as
clean as possible.
Keep cold until frozen.
Never stuff poultry before freezing.
Store-bought meats must be over-wrapped.
Freeze meats and poultry using the drugstore or
butcher wrap (drugstore wrap preferred except for
irregular meat cuts).
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45. Freezing Fish
Pre-treat as directed to control rancidity, flavor
changes or loss of liquid.
Package using one of the following:
Lemon-gelatin glaze
Ice glaze
Water
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46. Lemon-gelatin Glaze
Mix 1/4 cup lemon juice and 1-3/4 cups water.
Dissolve 1 packet unflavored gelatin into 1/2
cup of this mixture.
Heat remaining mixture to boiling and add
dissolved gelatin.
Cool, dip fish, wrap and freeze.
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47. Freezing Prepared Foods
Many can be frozen.
Follow directions in a credible freezer
publication.
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48. Foods that Do Not Freeze Well
Cabbage, celery, cress,
cucumbers, endive, lettuce,
parsley, radishes
White potatoes
Cooked macaroni, spaghetti,
rice
Egg whites
Meringue
Icings made from egg whites
Cream or custard filling
Milk sauces
Sour cream
Cheese
Mayonnaise or salad
dressing
Gelatin
Fruit jelly
Fried foods
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49. Thawing Foods for Serving
Fruits
Best if served with ice crystals present.
Thaw:
In refrigerator -- 6 to 8 hours per pound of fruit in
syrup
At room temperature -- 1 to 2 hours per pound
At room temperature in cool water -- 1/2 to 1 hour
per pound
In microwave oven - follow manufacturer’s
instructions.
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50. Thawing Foods for Serving
Dry sugar packs thaw faster than syrup packs.
Unsweetened packs thaw the slowest.
When used in recipes, allow for added sugar
and more juice.
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51. Thawing Foods for Serving
Vegetables
Cook without thawing except partially thaw corn-
on-the-cob and leafy greens.
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52. Thawing Foods for Serving
Meat, Poultry, and Fish
Can be cooked when thawed or frozen (might 1-1/2
times longer if cooked frozen).
Thaw:
In refrigerator
In microwave oven (follow manufacturer’s directions)
In cold water (keep water cold)
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56. Freezer Emergencies
If power will be off, set freezer controls to 10ºF
to -20ºF immediately.
Do not open door.
Foods stay frozen longer if freezer is full, well-
insulated, and in cool area.
Full freezer -- keeps 2 to 4 days
Half full freezer -- 24 hours
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57. Freezer Emergencies
If power interruption will be longer than 1 to
2 days, use dry ice:
50 lbs -- keeps full 20 cubic foot freezer below
freezing for 3 to 4 days
50 lbs -- keeps half-full freezer for 2 to 3 days
Keep dry ice on boards or heavy cardboard on
top of food.
Do not touch dry ice.
Do not open freezer.
Ventilate room.
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58. Refreezing Thawed Foods
Texture will not be as good.
General rule:
Refreeze if freezer temperature is 40ºF or colder or
if ice crystals are still present.
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59. Best Advice for Freezing
Freeze foods quickly.
Set freezer temperature at -10ºF 24 hours before
freezing foods.
Spread packages out until frozen, then stack.
Hold at 0ºF or colder for best quality.
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