How to safely defrost food?

June 13, 2023 | 05:35 pm PT
My family has a habit of storing frozen food for future use. How should I defrost food so it can be safely consumed? (Han, 30, HCMC).


Fresh food, when left at room temperature, creates favorable conditions for bacteria to grow. During meal prep, there exists the concept of "the danger zone", which is the temperature range of 8-63 degrees Celsius. Freezing food does not eradicate bacteria, it can only help prevent them from growing.

Therefore, the defrosting process easily creates conditions for bacteria to grow in this temperature range. With large amounts of food being frozen for future use, we need to pay attention to the defrosting process.

The most common way is to defrost food in the cool refrigerator compartment. Food should be kept in the lowest compartment to prevent water from leaking onto other foods.

In case you need to defrost things quickly, a microwave is a great option. Before putting food in the oven, it is necessary to remove unsafe packaging such as polystyrene trays, plastic food wrap or paper cartons.

It is necessary to place food in a microwave-safe container. To avoid water leakage during defrosting, it is recommended to use a container with a lid and a vent. It will be difficult for heat to penetrate the entire block of food that needs to be thawed, so it is necessary to mix them up.

Another common way to defrost is to use cold water. However, this method can easily put the food in the dangerous temperature range, creating opportunities for bacteria growth. When using this method, it is necessary to allow the entire mass of food to be submerged in water.

Food needs to be wrapped in waterproof, leak-free packaging to avoid cross-contamination. The defrosting process should only last for two hours or less to avoid putting food in the dangerous temperature range (8-63 degrees Celsius).

Even food wrapped in waterproof packaging still has bacteria attached to the surface. Therefore, it is necessary to clean the wash basin after food has been thawed.

Defrosted food should be cooked within the first 24 hours. If it is not possible to cook immediately, it should be stored in the cool refrigerator compartment.

In case processed food needs to be frozen for gradual use, it is recommended to divide it into portions which are just enough for one meal. It is best to store it in a glass container. When you’re ready to eat, defrost that portion in the microwave.

Dr. Pham Anh Ngan

The HCMC University Hospital of Medicine and Pharmacy

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