HOW CAN PEOPLE PROTECT THEMSELVES?
Leftovers should be hot when they need to be hot, and cold when they need to be cold. It’s all about minimising the time they spend in the danger zone (at which toxins can grow). This danger zone is anything above the temperature of your fridge, and below 60 degrees Celsius, which is the temperature to which you should reheat your food.
After cooking a meal, if you’re going to keep some of it to eat over the following days, refrigerate the leftovers promptly. There’s no need to wait for the food to cool.
Also, if you can, break a large batch up into smaller portions. When you put something in the fridge, it takes time for the cold to penetrate the mass of the food, so smaller portions will help with this. This will also minimise the times you’re taking the food out of the fridge.
As a general guide, you can follow the two hour/four hour rule. So if something has been out of the fridge for up to two hours, it’s safe to put it back. If it’s been out for longer, consume it then and then throw away the leftovers. If it’s been out for longer than four hours, it starts to become a risk.
The common adage of food safety applies here: If in doubt, throw it out.
It’s also worth keeping in mind the general principles of food hygiene. Before preparing food, wash your hands. Use clean utensils, and don’t cross-contaminate cooked food with raw food.
Enzo Palombo is Professor of Microbiology, Swinburne University of Technology. This commentary first appeared in The Conversation.