Freezing Food Safely
Foods in the freezer -- are
Every year, thousands of callers to the USDA Meat and Poultry
Hotline aren't sure about the safety of items stored in their own
home freezers. The confusion seems to be based on the fact that few
people understand how freezing protects food. Here is some
information on how to freeze food safely and how long to keep it.
What Can You Freeze?
You can freeze almost any food. Some exceptions are canned food or
eggs in shells. However, once the food (such as a ham) is out of the
can, you may freeze it.
Being able to freeze food and being pleased with the quality after
defrosting are two different things. Some foods simply don't freeze
well. Examples are mayonnaise, cream sauce and lettuce. Raw meat and
poultry maintain their quality longer than their cooked counterparts
because moisture is lost during cooking.
Is Frozen Food Safe?
Food stored constantly at 0 °F will always be safe. Only the quality
suffers with lengthy freezer storage. Freezing keeps food safe by
slowing the movement of molecules, causing microbes to enter a
dormant stage. Freezing preserves food for extended periods because
it prevents the growth of microorganisms that cause both food
spoilage and foodborne illness.
Does Freezing Destroy Bacteria &
Freezing to 0 °F inactivates any microbes -- bacteria, yeasts
and molds - - present in food. Once thawed, however, these microbes
can again become active, multiplying under the right conditions to
levels that can lead to foodborne illness. Since they will then grow
at about the same rate as microorganisms on fresh food, you must
handle thawed items as you would any perishable food.
Trichina and other parasites can be destroyed by sub-zero freezing
temperatures. However, very strict government-supervised conditions
must be met. It is not recommended to rely on home freezing to
destroy trichina. Thorough cooking will destroy all parasites.
Freshness & Quality
Freshness and quality at the time of freezing affect the condition
of frozen foods. If frozen at peak quality, foods emerge tasting
better than foods frozen near the end of their useful life. So
freeze items you won't use quickly sooner rather than later. Store
all foods at 0° F or lower to retain vitamin content, color, flavor
The freezing process itself does not destroy nutrients. In meat and
poultry products, there is little change in nutrient value during
Enzyme activity can lead to the deterioration of food quality.
Enzymes present in animals, vegetables and fruit promote chemical
reactions, such as ripening. Freezing only slows the enzyme activity
that takes place in foods. It does not halt these reactions which
continue after harvesting. Enzyme activity does not harm frozen
meats or fish and is neutralized by the acids in frozen fruits. But
most vegetables that freeze well are low acid and require a brief,
partial cooking to prevent deterioration. This is called
"blanching." For successful freezing, blanch or partially cook
vegetables in boiling water or in a microwave oven. Then rapidly
chill the vegetables prior to freezing and storage. Consult a
cookbook for timing.
Proper packaging helps maintain quality and prevent "freezer burn."
It is safe to freeze meat or poultry
directly in its market wrapping but this type of
wrap is permeable to air. Unless you will be using the food in a
month or two, overwrap these packages as you would any food for
long-term storage using airtight heavy-duty foil, (freezer) plastic
wrap or freezer paper, or place the package inside a (freezer)
plastic bag. Use these materials or airtight freezer containers to
repackage family packs into smaller amounts. It is not necessary to
rinse meat and poultry before freezing. Freeze unopened vacuum
packages as is. If you notice that a package has accidentally been
torn or has opened while food is in the freezer, the food is still
safe to use; merely overwrap or rewrap it.
Freezer burn does not make food unsafe, merely dry in spots. It
appears as grayish-brown leathery spots and is caused by air
reaching the surface of the food. Cut freezer-burned portions away
either before or after cooking the food. Heavily freezer-burned
foods may have to be discarded for quality reasons.
Color changes can occur in frozen foods. The bright red color of
meat as purchased usually turns dark or pale brown depending on its
variety. This may be due to lack of oxygen, freezer burn or
abnormally long storage.
Freezing doesn't usually cause color changes in poultry. However,
the bones and the meat near them can become dark. Bone darkening
results when pigment seeps through the porous bones of young poultry
into the surrounding tissues when the poultry meat is frozen and
The dulling of color in frozen vegetables and cooked foods is
usually the result of excessive drying due to improper packaging or
Freeze food as fast as possible to maintain its quality. Rapid
freezing prevents undesirable large ice crystals from forming
throughout the product because the molecules don't have time to take
their positions in the characteristic six-sided snowflake. Slow
freezing creates large, disruptive ice crystals. During thawing,
they damage the cells and dissolve emulsions. This causes meat to
"drip"--lose juiciness. Emulsions such as mayonnaise or cream will
separate and appear curdled.
Ideally, a food 2-inches thick should freeze completely in about 2
hours. If your home freezer has a "quick-freeze" shelf, use it.
Never stack packages to be frozen. Instead, spread them out in one
layer on various shelves, stacking them only after frozen solid.
Refrigerator - Freezers
If a refrigerator freezing compartment can't maintain zero degrees
or if the door is opened frequently, use it for short-term food
storage. Eat those foods as soon as possible for best quality. Use a
free-standing freezer set at 0° F or below for long-term storage of
frozen foods. Keep a thermometer in your freezing compartment or
freezer to check the temperature. This is important if you
experience power-out or mechanical problems.
Length of Time
Because freezing keeps food safe almost indefinitely, recommended
storage times are for quality only. Refer to the freezer storage
chart at the end of this document, which lists optimum freezing
times for best quality.
If a food is not listed on the chart, you may determine its quality
after defrosting. First check the odor. Some foods will develop a
rancid or off odor when frozen too long and should be discarded.
Some may not look picture perfect or be of high enough quality to
serve alone but may be edible; use them to make soups or stews. Cook
raw food and if you like the taste and texture, use it.
Never defrost foods in a garage, basement, car, dishwasher or
plastic garbage bag; out on the kitchen counter, outdoors or on the
porch. These methods can leave your foods unsafe to eat.
There are three safe ways to defrost food: in the refrigerator, in
cold water, or in the microwave. It's best to plan ahead for slow,
safe thawing in the refrigerator. Small items may defrost overnight;
most foods require a day or two. And large items like turkeys may
take longer, approximately one day for each 5 pounds of weight.
For faster defrosting, place food in a leak proof plastic bag and
immerse it in cold water. (If the bag leaks, bacteria from the air
or surrounding environment could be introduced into the food.
Tissues can also absorb water like a sponge, resulting in a watery
product.) Check the water frequently to be sure it stays cold.
Change the water every 30 minutes. After thawing, cook immediately.
When microwave-defrosting food, plan to cook it immediately after
thawing because some areas of the food may become warm and begin to
cook during microwaving.
Once food is thawed in the
refrigerator, it is safe to refreeze it without cooking,
although there may be a loss of quality due to the moisture lost
through defrosting. After cooking raw foods which were previously
frozen, it is safe to freeze the cooked foods. If previously cooked
foods are thawed in the refrigerator, you may refreeze the unused
If you purchase previously frozen meat, poultry or fish at a retail
store, you can refreeze if it has been handled properly.
Cooking Frozen Foods
Raw or cooked meat, poultry or casseroles can be cooked or reheated
from the frozen state. However, it will take approximately one and a
half times the usual cooking time for food which has been thawed.
Remember to discard any wrapping or absorbent paper from meat or
When cooking whole poultry, remove the giblet pack from the cavity
as soon as you can loosen it. Cook the giblets separately. Read the
label on USDA-inspected frozen meat and poultry products. Some, such
as pre-stuffed whole birds, MUST
be cooked from the frozen state to ensure a safely cooked product.
Power Outage in Freezer
If there is a power outage, the freezer fails, or if the freezer
door has been left ajar by mistake, the food may still be safe to
use. As long as a freezer with its door ajar is continuing to cool,
the foods should stay safe overnight. If a repairman is on the way
or it appears the power will be on soon, just don't open the freezer
A freezer full of food will usually keep about 2 days if the door is
kept shut; a half-full freezer will last about a day. The freezing
compartment in a refrigerator may not keep foods frozen as long. If
the freezer is not full, quickly group packages together so they
will retain the cold more effectively. Separate meat and poultry
items from other foods so if they begin to thaw, their juices won't
drip onto other foods.
When the power is off, you may want to put dry ice, block ice, or
bags of ice in the freezer or transfer foods to a friend's freezer
until power is restored. Use an appliance thermometer to monitor the
When it is freezing outside and there is snow on the ground, it
seems like a good place to keep food until the power comes on;
however, frozen food can thaw if it is exposed to the sun's rays
even when the temperature is very cold. Refrigerated food may become
too warm and foodborne bacteria could grow. The outside temperature
could vary hour by hour and the temperature outside will not protect
refrigerated and frozen food. Additionally, perishable items could
be exposed to unsanitary conditions or to animals. Animals may
harbor bacteria or disease; never consume food that has come in
contact with an animal.
To determine the safety of foods when the power goes on, check their
condition and temperature. If food is partly frozen, still has ice
crystals, or is as cold as if it were in a refrigerator (40 °F), it
is safe to refreeze or use. It's not necessary to cook raw foods
before refreezing. Discard foods that
have been warmer than 40 °F for more than 2 hours. Discard any foods
that have been contaminated by raw meat juices.
Dispose of soft or melted ice cream for quality's sake.
Accidentally frozen cans, such as those left in a car or basement in
sub-zero temperatures, can present health problems. If the cans are
merely swollen -- and you are sure the swelling was caused by
freezing -- the cans may still be usable. Let the can thaw in the
refrigerator before opening. If the product doesn't look and/or
smell normal, throw it out. DO NOT TASTE IT! If the seams have
rusted or burst, throw the cans out immediately, wrapping the burst
can in plastic and disposing the food where no one, including
animals can get it.
Shell eggs should not be frozen. If an egg accidentally freezes and
the shell cracked during freezing, discard the egg. Keep an
uncracked egg frozen until needed; then thaw in the refrigerator. It
can be hard cooked successfully but other uses may be limited.
That's because freezing causes the yolk to become thick and syrupy
so it will not flow like an unfrozen yolk or blend very well with
the egg white or other ingredients.
Freezer Storage Chart (0 °F)
Note: Freezer storage is for quality only. Frozen foods remain safe
|Bacon and Sausage
||1 to 2
||2 to 3
|Egg whites or egg
|Frozen Dinners and Entrees
||3 to 4
|Gravy, meat or poultry
||2 to 3
|Ham, Hotdogs and
||1 to 2
|Meat, uncooked roasts
||4 to 12
|Meat, uncooked steaks or
||4 to 12
|Meat, uncooked ground
||3 to 4
||2 to 3
|Poultry, uncooked whole
|Poultry, uncooked parts
|Poultry, uncooked giblets
||3 to 4
|Soups and Stews
||2 to 3
|Wild game, uncooked
||8 to 12
USDA Meat and Poultry
Hotline: 1-888-674-6854 (1-888-MPHotline)
Food Safety Inspection
Article Courtesy of the
Food Safety Inspection