Does Freezing Destroy Bacteria and Parasites?
Freezing at 0°F does not destroy microbes—bacteria, yeasts, and molds—present in food; instead it inactivates them. Once thawed these microbes can again become active, multiplying under the right conditions to levels that can lead to food-borne illness. Since they will grow at about the same rate as microorganisms on fresh food, you must handle thawed items as you would any perishable food.
Thorough cooking will destroy all bacteria and parasites.
Freezer Burn
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
Color changes can occur in frozen foods. The bright red color of meat as purchased usually turns dark or pale brown depending on the variety. This may be due to lack of oxygen, freezer burn, or long storage.
Freezing doesn’t usually cause color changes in poultry. However, the bones and the flesh 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 is frozen and thawed.
The dulling of color in frozen vegetables and cooked foods is usually the result of excessive drying due to improper packaging or over lengthy storage.
Freeze Rapidly
Freeze food as fast as possible after purchasing or preparing to maintain its quality. Slow freezing creates large, disruptive ice crystals. During thawing, they damage the cells and dissolve emulsions. This causes meat to “drip,” or lose its juiciness. Rapid freezing prevents these undesirable large crystals from forming throughout the product because the molecules don’t have time to take their positions in the characteristic six-sided snowflake.
Ideally, a food 2 inches thick should freeze completely in about 2 hours. If your home freezer has a “quick-freeze” shelf, use it.
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 a power outage 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 section, 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.
Power Outage in Freezer
If there is a power outage and the freezer fails, or if the freezer door has been left ajar by mistake, the food inside 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 door.
A freezer full of food will usually keep for about two days if the door is kept shut; a half-full freezer will last for 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 temperature.
When it is freezing outside and there is snow on the ground, the outdoors 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 food-borne 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.
FREEZER STORAGE CHART (0°F)
These guidelines are for quality only. Frozen foods remain safe indefinitely.
|
Item |
Months | |||
|
Bacon and sausage |
1 to 2 | |||
|
Casseroles |
2 to 3 | |||
|
Egg whites or nonfat egg substitutes |
12 | |||
|
Gravy, meat, or poultry |
2 to 3 | |||
|
Ham, hot dogs, and lunch meats |
1 to 2 | |||
|
Meat, uncooked roasts |
4 to 12 | |||
|
Meat, uncooked steaks or chops |
4 to 12 | |||
|
Meat, uncooked ground |
3 to 4 | |||
|
Meat, cooked |
2 to 3 | |||
|
Poultry, uncooked whole |
12 | |||
|
Poultry, uncooked parts |
9 | |||
|
Poultry, uncooked giblets |
3 to 4 | |||
|
Poultry, cooked |
4 | |||
|
Soups and stews |
2 to 3 | |||
|
Wild game, uncooked |
8 to 12 |
A Primer on Freezer Styles
There are three types of freezers on the market: upright, chest, and refrigerator-freezer combinations. The upright and refrigerator freezer are available as manual-defrost or frost-free models. Though less convenient, manual-defrost freezers are more cost efficient. They also maintain higher-quality food than do frostless models because they don’t have a fan running to remove the moisture that would turn to frost. The constant removal of moisture from the freezer could cause freezer burn in improperly wrapped food. Frost-free chest freezers are not available, but frost builds up in chest freezers less readily.
Upright Freezers: These appliances have the same general shape and appearance as home refrigerators. They have one or two outside doors and from three to seven shelves for storing food. Freezers of this type are popular due to their convenience, the small floor space they require, and the ease with which food may be put in or removed. However, more cold air escapes each time the door is opened.
Chest Freezers: Freezers of this type require more floor area than the uprights but are more economical to buy and operate. These freezers lose less cold air each time they’re opened. Make sure this type of freezer is equipped with sliding or lift-out baskets to permit easy loading and removal of food.
Refrigerator-Freezer Combination: This is a single appliance with one or two doors. It has one compartment for frozen foods and another for refrigerated foods. The freezing compartments may be above, below, or to one side of the refrigerated area. If selecting this type, be certain that the freezer is a true freezer (will maintain 0°F or less) and not just a freezing compartment.