Why putting hot food straight into fridge is safer

The head of the Clinical Nutrition Department at Anhui Medical University Hospital in China said food should be refrigerated as soon as possible, even while still hot, as a rule of thumb for safe storage.

Food safety risks are linked to the "danger temperature zone" between 4 and 60 degrees C, where bacteria such as Salmonella, Staphylococcus aureus and E. coli multiply rapidly, according to the People’s Daily newspaper.

Bacterial growth is slowed below 4 degrees C, the standard temperature of a refrigerator compartment, and they are killed at above 60 degrees C.

If food is left to cool naturally, the time it spends in the "danger zone" is prolonged, increasing the risk of contamination. Health authorities advise that cooked food should not be left at room temperature for more than two hours, or one hour if the ambient temperature exceeds 32 degrees C.

The US Department of Agriculture says hot food can be placed directly into the refrigerator, and classifies the belief that food must cool first as a common food safety myth.

Modern refrigerators are designed to handle higher temperatures, with sensors and cooling systems that prevent damage. Any additional power consumption is minimal compared with the health benefits of proper food storage.

Storage methods also affect food safety. J. Kenji Lopez-Alt, author of the food science book The Food Lab, said the biggest mistake is not refrigerating hot food but placing large pots directly into the refrigerator.

He said large volumes of food retain heat over extended periods of time, allowing bacteria to grow inside the refrigerator even when the surface appears cool.

To store food safely, home cooks are advised to follow four rules:

Portioning: Instead of storing an entire pot, food should be transferred into smaller containers with a depth of less than 5 cm to speed up cooling.

Do not seal immediately: If the food is still hot, leave the lid slightly open during the first hour in the refrigerator to release steam and prevent condensation. Once cooled, containers should be sealed to reduce cross-contamination and odor transfer.

Allow airflow: Containers should be spaced slightly apart in the refrigerator to allow cold air to circulate.

Limit storage time: Refrigeration slows but does not eliminate bacterial growth. Cooked vegetables should be stored in the refrigerator for no more than 24 hours, while cooked meat should not exceed two days.