THAWING IS the process of warming food that has been frozen until there is no residual ice left. This is done so the food can be prepared or eaten properly. Thawing may sounds like a simple process, but it is not. And improper thawing of food may lead to serious problems, particularly food-borne illnesses. This is especially the case for frozen poultry, meats, and seafood. These are highly perishables for several reasons. One of this is that they are rich in nutrients that spoilage and disease-causing bacteria need to survive.
Optimal (room temperature) temperature speeds things up. Remember that freezing food only slows down the growth of these microorganisms—they do not die from freezing temperatures. Once the temperature becomes optimal again, microbial activity accelerates. In most cases of improper thawing, the center of the meat is still in its frozen state, but the outer layer could be already in the so-called temperature danger zone (TDZ). The TDZ is between 40°F (4 °C) and 140 °F (60 °C), where bacterial growth doubles in as little as 20 minutes. So allowing food to sit at room temperature allows the bacterial population to grow at dangerous levels that make the food unfit for consumption.
Here are a few tips for safe thawing of frozen foods.
THAWING IN THE REF IS BEST. Room temperature speeds up the thawing process, but it works greatly only on the outside, but the core remains frozen. The soft outside portion of the food becomes an ideal environment for bacterial growth. To prevent uneven thawing, place food in the refrigerator. The temperature is above freezing, but it prevents food from being in the TDZ.
ONLY COOK FROZEN FOOD IN SMALL PORTIONS. Large cuts of poultry, meat, and fish run the risk of being under-cooked in the center but burned on the outside. For this reason, it is recommended to cook frozen food in small portions. Thin to medium thickness fish fillets are best, especially in taste and texture.
REFREEZE FOOD ONLY ONCE. Do not refreeze food that has been left outside the refrigerator for 2 hours. The FDA recommends discarding perishables left at room temperature for 2 hours.
Although freezing thawed meat is fine, quality loss may occur as a result of moisture loss and fat oxidation. This is especially the case for home freezers, where freezing takes longer. The longer the time it takes to freeze the meat, the larger the ice crystals that form, which pierce the meat structure. When the meat is thawed, the meat loses moisture and becomes less juicy and tender.
ROTATE FOOD AS IT DEFROSTS. This is especially important for meat in large cuts or sizes, where defrosting takes longer. Rotating the frozen food allows uniform distribution of heat as the food reaches a safe internal temperature. This works by liberating ice that may be trapped under the food. Rotating food periodically is necessary if thawing in the microwave oven that does not have a turntable that rotates automatically. Thawing in the microwave requires immediate cooking because some areas of the food may start cooking during thawing. By Manny Palomar, PhD (EV Mail January 2-8, 2023 issue)