Reheating and then cooling food a second time can be very risky. This process takes the food through the "danger zone" (5°C to 50°C) multiple times, which can increase the chance of harmful bacteria growing. Once food has been reheated, it should either be eaten immediately or discarded if not used.
Common misunderstanding: It's safe to reheat and cool food multiple times as long as it's done quickly.
Even if reheating and cooling are done quickly, repeatedly taking food through the danger zone can still promote bacterial growth. Each cycle increases the risk of contamination, making the food unsafe to eat.
Common misunderstanding: If food smells and looks fine after multiple reheats, it's safe to eat.
Food can look and smell normal even when it's not safe. Bacteria like Salmonella and E. coli can grow without changing the look or smell of the food. Always follow safe food handling practices to avoid risks.
When food is reheated and then cooled, it passes through the temperature range of 5°C to 50°C, known as the danger zone. This is where bacteria can grow rapidly. Repeatedly moving food through this zone can significantly increase the risk of foodborne illnesses.
Common misunderstanding: A quick pass through the danger zone is harmless.
Even a brief time in the danger zone can be enough for bacteria to start multiplying. It's important to minimise the time food spends in this temperature range.
Common misunderstanding: All bacteria are killed during cooking, so reheating is just about warming the food up.
Some bacteria can form spores that survive cooking. These can become active again and multiply if the food is improperly reheated and cooled.
Repeated heating and cooling cycles can compromise food safety by allowing bacteria to multiply during each cycle through the danger zone. This increases the risk of creating conditions that are conducive to foodborne illnesses.
Common misunderstanding: Frequent heating and cooling cycles don't affect the food's safety if the food is refrigerated quickly each time.
Quick refrigeration does not negate the risk of bacteria multiplication if the food has been through multiple heating and cooling cycles. Each cycle is a risk.
Common misunderstanding: Using a microwave or blast chiller effectively resets the safety of the food with each cycle.
While these appliances can control the temperature quickly, they do not remove the toxins produced by bacteria that might have multiplied during previous cycles. Safety is not just about temperature, but also about preventing bacterial growth and toxin production.