Safely defrosting frozen food so its outer layers do not sit in the temperature danger zone while the centre thaws.
Safely defrosting frozen food so its outer layers do not sit in the temperature danger zone while the centre thaws. Thawing, or defrosting, is the process of bringing frozen food back to a state where it can be safely prepared and cooked. The main risk during thawing is that the outer surface of the food warms into the temperature danger zone, between 5 and 60 degrees Celsius, where bacteria can multiply, while the centre is still frozen. Slow, controlled thawing keeps the whole food out of that risk range for as long as possible. There is no single thawing rule in the Food Standards Code, but the general requirement is that potentially hazardous food must be kept under temperature control so it does not become unsafe. Safe methods include thawing in the refrigerator, thawing as part of the cooking process, or using a microwave when the food will be cooked straight afterwards. Thawing food on the bench at room temperature is discouraged because the surface can spend too long in the danger zone. In an Australian kitchen, the safest routine is to plan ahead and thaw frozen food in the fridge, on a tray to catch drips, and placed below or away from ready-to-eat foods to avoid cross-contamination. Larger items such as whole poultry can take a day or more to thaw fully, so batch planning matters. Food that has been thawed should be treated as perishable and kept under 5 degrees Celsius until cooked. Once thawed, food should not be refrozen unless it has been cooked in between, as repeated freezing and thawing increases risk and reduces quality. The two-hour four-hour guidance can help judge whether thawed food that spent time out of refrigeration is still safe. A pub kitchen takes frozen chicken breasts out of the freezer the night before service and places them in a covered tray on the bottom shelf of the cool room. By the next morning they are fully thawed at under 5 degrees Celsius, kept away from salad ingredients, and ready to cook, with no time spent thawing on the bench.
Frequently asked questions
What is the safest way to thaw food?
Thawing in the refrigerator is the safest general method, because it keeps the food cold and out of the temperature danger zone while it defrosts.
Can you thaw food on the bench at room temperature?
This is discouraged, because the outer surface can sit in the temperature danger zone between 5 and 60 degrees Celsius for too long while the centre is still frozen.
Can thawed food be refrozen?
Thawed food should not be refrozen unless it has been cooked in between. Repeated freezing and thawing increases food safety risk and reduces quality.
Why is thawing a food safety risk?
During thawing the surface of the food can warm into the temperature danger zone and allow bacteria to grow, even while the centre remains frozen.
Can you thaw food in the microwave?
Yes, if the food is cooked immediately afterwards, because microwave thawing can leave warm spots where bacteria could grow if the food is left standing.
