Olympic Norovirus & Other Infections: What You Need to Know

[리얼푸드=육성연 기자] An emergency was declared due to the spread of norovirus at the 2026 Milan/Cortina d’Ampezzo Winter Olympics. Following the Finnish women’s ice hockey team, infections also occurred in the Swiss women’s ice hockey team. Even in Korea, special precautions are needed to prevent infection.

Usually, the risk of food poisoning decreases as the weather gets colder, but norovirus is an exception. Rather, it is rampant in winter. It has strong resistance to low temperatures. Infectivity is maintained even at -20 degrees Celsius.

The transmission power is also strong. As few as 10 to 100 virus particles can cause infection. The main route of transmission is through eating contaminated food or water. You can also become infected when you come into contact with a contaminated surface or an infected person.

Survival is also long. They survive on contaminated surfaces from several days to several months.

Oysters are well known as a food with a high risk of infection. Norovirus mixed in seawater can easily become concentrated in oysters. In particular, oysters live in shallow coastal areas, and these areas are more affected by polluted water flowing in from the land. Moreover, oysters, which are in season in winter, are often eaten raw. If oysters contain norovirus, you can become infected not only by eating them raw but also by eating them without sufficiently heating them.

In addition to oysters, you can become infected through many foods. You should also be careful with ‘leaf vegetables’ such as lettuce and cabbage and ‘ice’. In particular, ice has a very strong survivability, although the level of awareness regarding norovirus is low. If you frequently drink ice drinks, including iced Americano in the winter, you need to be careful about hygiene.

This was also confirmed in an actual experiment conducted by the Ministry of Food and Drug Safety (2013). The researchers measured the survival rate of foods such as tomatoes, lettuce, and ice after contaminating them with norovirus.

The results were different from expectations. There was a high risk of infection when eating vegetables such as lettuce or perilla leaves without washing them. The norovirus survival rate in tomatoes was 11% on the 3rd day and 9% on the 6th day. It reached 5% on the 10th day. Norovirus in lettuce survived up to 27% on the 3rd day, 11% on the 6th day, and 3% on the 10th day.

The norovirus in the ice was stronger. Live norovirus remained on the ice even at -20 degrees Celsius. Even after 3 days, up to 99% survived. Even after 17 days, about 45% survived. If the ice in Iced Americano is contaminated, you can get enteritis from eating it.

In a food-specific survey by the U.S. Centers for Disease Control and Prevention (CDC), leafy vegetables were the most common cause of infection. When researchers analyzed foods that caused norovirus between 1998 and 2008, leafy vegetables accounted for the largest proportion (32%). This was followed by fruits and nuts (17%) and fish and shellfish (13%).

According to the Ministry of Food and Drug Safety, to prevent norovirus, raw vegetables must first be thoroughly washed. Even if you wash and store it in the refrigerator, it is safe to wash it again before eating. The Ministry of Food and Drug Safety said, “It is best to soak leafy vegetables in water for at least 2 minutes and then wash thoroughly under running water.”

For ice, wash the ice cube tray thoroughly with water. Ice produced with water purifiers is also managed regularly to prevent bacteria from multiplying. The water used for ice is also important. You can prevent norovirus by using boiled or purified water.

Storage method is also important. Food contaminated with norovirus is highly contagious, so it is easy to cross-contaminate other foods. It is advisable to store each food item in a separate container. In addition, when preparing food, be sure to wash your hands thoroughly with detergent.

The best prevention method recommended by the Ministry of Food and Drug Safety is to eat it ‘heated’. Norovirus disappears when heated at 85℃ for more than 1 minute.

gorgeous@heraldcorp.com