Food must be kept at a safe temperature during "the big thaw." While frozen, foods are safe indefinitely. However, as soon as food begins to defrost, any bacteria which may have been present before freezing can begin to grow again.
"A package of frozen meat or poultry left thawing on the counter more than two hours, or overnight is not at a safe temperature," cautions Bessie Berry, acting director of the USDA Meat and Poultry Hotline.
Even though the center of the package may still be frozen, the outer layer of the food is in "the danger zone" between 40 degrees F and 140 degrees F -- at a temperature when bacteria multiply rapidly.
"When defrosting frozen foods, it's best to plan ahead and thaw food in the refrigerator where food will remain at a safe, constant temperature -- 40 degrees F or below," recommends Berry.
There are three safe ways to defrost food: in the refrigerator, in cold water and in the microwave.
Refrigerator Thawing requires planning ahead due to the time involved. A large frozen item like a turkey requires at least a day (24 hours) for each 5 pounds of weight. Even small amounts of frozen food -- such as a pound of ground meat or boneless chicken breasts -- require a full day to thaw.
When thawing foods in the refrigerator, there are several variables to take into account.
- Some areas of an appliance may keep the food colder than others. Food placed in the coldest part will require longer defrosting time.
- Many callers to the Hotline report that frozen turkeys in refrigerators with glass shelves seem to require longer defrosting time than in refrigerators with wire shelves.
- Food takes longer to thaw in a refrigerator set at 35 degrees F than one set at 40 degrees F.
After thawing in the refrigerator, ground meat and poultry should remain safe for an additional day or two before cooking, red meat, 3 to 5 days.
Foods defrosted in the refrigerator can be refrozen without cooking although there may be some loss of quality.
Cold Water Thawing is faster than refrigerator thawing but requires more attention. First be sure the food is in a leak-proof package or plastic bag. 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.
Immerse the bag in cold tap water. Check the water frequently to be sure it stays cold. Change the water every 30 minutes until the product is thawed. After thawing, refrigerate the food until ready to use.
Foods thawed by the cold water method should be cooked before refreezing.
Microwave Thawing. 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. Holding partially cooked food is not recommended because any bacteria present wouldn't have been destroyed.
Foods thawed in the microwave should be cooked before refreezing.
For additional food safety information about meat, poultry or eggs, call the toll-free USDA Meat and Poultry Hotline at 1 (800) 535-4555. It is staffed by home economists, registered dietitians and food technologists from 10 a.m. to 4 p.m. ET year round. An extensive selection of food safety recordings can be heard 24 hours a day using a touch-tone phone.
