Virus Risks in Frozen Foods and Safe Storage

Public attention to food increased noticeably during the pandemic; reports said that viruses had been detected in samples from frozen products in some countries. These developments raised questions about how to ensure the safety of frozen foods during both production and consumption. Statements from the World Health Organization and the U.S. Centers for Disease Control and Prevention said that the likelihood of transmission to people from food or food packaging was very low. Below is an overview of foodborne viruses and ways to store frozen foods safely.

Viruses found in food
Hepatitis A and hepatitis E viruses, rotaviruses, noroviruses, and caliciviruses are among the enteric viruses that can be transmitted through water and food; these viruses are said to spread primarily through the fecal-oral route. Food can become contaminated with these viruses at any stage, before or after processing. Because viruses cannot reproduce on their own, they are generally present in low numbers in contaminated foods; the risk mainly increases when these foods are stored improperly. For this reason, food-safety practices play an important role in preventing transmission to people.

Proper storage temperatures
Because foodborne bacteria grow rapidly between 4°C / 40°F and 60°C / 140°F, it is important to maintain the cold chain. Foods that require refrigeration should not be left at room temperature for more than 2 hours. Frozen products should be kept at the temperature stated on the label, generally −18°C / 0°F or below. After shopping, taking frozen foods home as soon as possible and placing them in the freezer helps prevent a break in the cold chain. Do not buy frozen products with damaged or swollen packaging, as this may indicate that the product’s safety has been compromised.

Safe thawing methods
Frozen foods should not be left to thaw on the kitchen counter at room temperature; this can keep the outer surface of the food in a risky temperature range for a long time. Instead, transferring the product to the upper shelf of the refrigerator one day before and letting it thaw slowly is a much safer method. If faster thawing is needed, the food can be placed in cold water in its sealed package or thawed using the microwave defrost setting; food thawed using these methods should be cooked without delay. Food thawed in the refrigerator can be refrozen without cooking, although its texture may suffer; food thawed in cold water or in the microwave should be cooked before it is refrozen.

Packaging and shopping safety
Keep frozen food packaging clean until you get home, and avoid contact with other fresh foods when removing it from shopping bags. Washing your hands after touching the packaging is one of the most basic general food-hygiene steps. Carry frozen products separately from raw meat and poultry in the shopping cart and bags; this separation reduces the risk of cross-contamination. Pick up frozen products at the very end of shopping and take them home without leaving them in warm conditions.

General food-safety practices
Although health authorities say the risk of virus transmission through food is low, following basic food-safety practices is always recommended; these practices apply to bacterial contamination risks as well as viruses. Clean kitchen surfaces and utensils regularly. Adequate internal cooking temperatures are said to inactivate most foodborne microorganisms, so it is important to cook meat and poultry thoroughly. Frequent handwashing and regularly replacing kitchen towels help maintain general hygiene.