Answer:
Freezing is an effective way of maintaining the nutritional value, quality, and flavor of many kinds of food. Unlike food stored in a cooler, which is more easily perishable, frozen food is generally safe to consume after its expiration date.
Normally, storing at -17 degrees Celsius will neutralize bacteria that causes food spoilage. However, if you regularly open the freezer door and the food is left at temperatures higher than -17 degrees Celsius, the chances of spoilage increase.
Although expired foods can be used safely, they will lose quality and flavor after being left in the refrigerator for too long.
Meat, including poultry and fish, can maintain their quality for longer periods of time when they are frozen raw due to their higher moisture content. The freezing time of fruits and vegetables varies depending on how the food is prepared, packaged and stored.
Some vegetables such as cabbage, potatoes, celery and cucumbers cannot be frozen completely; at the same time, due to their high water content, they can be mushy after being defrosted.
Here is how long it takes to maintain the quality and freshness of some foods kept in the freezer at -17 degrees Celsius:
Vegetables and fruits can be kept in the freezer for 8-12 months; raw pork or beef for 3-4 months; whole chickens for 12 months; cold or processed meats (bacon, sausages) for 1-2 months; cooked fish for 4-6 months; fresh or grilled beef for 4-12 months.
There are some steps you can take to ensure frozen foods are safely edible, such as keeping a thermometer in the freezer to always maintain a temperature of -17 degrees Celsius; avoid placing hot food in the freezer (they should be allowed to cool down at room temperature); and trying not to open the freezer too often.
All kinds of meat should be tightly covered in air-tight condiments. Food should also be divided into small portions for easier defrosting.
Dr. Ta Tung Duy
The Vietnam Institute of Applied Medicine