What are foodborne viruses?
A foodborne illness is caused by eating food or drinking a beverage that is contaminated by bacteria, viruses or parasites.
In the European Union, viruses are estimated to be responsible for almost 12% of all foodborne outbreaks in 2007. In the UK is estimated that viruses are responsible for 18% of UK foodborne disease.
Viruses are tiny, very transmissible agents that can cause disease. Viruses consist of DNA or RNA enclosed in a protein coat. Viruses can only replicate inside other living cells. Certain virus can survive and remain infectious in food, water and the environment for a long time and can last through severe conditions such as heat, drying or freezing.
How can food be contaminated with viruses?
Viruses do not grow in foods. Foodborne viruses come from the intestines of humans and animals, so are commonly shed in faeces or other body fluids.
Illness is caused by:
- Eating food contaminated by food handlers infected by a virus due to poor food hygienic practices.
- Eating food contaminated with animal waste, human waste or sewage-polluted water.
- Eating food products from animals contaminated with viruses.
What viruses most commonly cause foodborne illness?
Most foodborne illnesses are caused by a very small number of viruses including:
- Norovirus, which causes gastroenteritis; symptoms include diarrhoea, vomiting and abdominal pain. The foods most associated with Norovirus include uncooked shellfish, raw fruits and vegetables, however other foods can become contaminated through food handlers using poor food hygiene practices.
- Hepatitis A, which causes liver inflammation, fever, loss of appetite, diarrhoea, nausea, abdominal discomfort, dark-coloured urine and jaundice. Not everyone infected with Hepatitis A will show all symptoms. The foods most associated with Hepatitis A are uncooked shellfish, raw fruit and vegetables and imported frozen berries which should be boiled for one minute before eating.
- Hepatitis E, which causes inflammation of the liver, again not everyone infected with Hepatitis E will show symptoms. Food commonly associated with Hepatitis E are raw/undercooked pork meat and liver.
How can I avoid getting infected by foodborne viruses?
- Washing hands
- Cooking shellfish fully before eating
- Making sure pork and pork products are fully cooked - including whole cuts of pork, pork products and offal. It is fully cooked when thickest part of the meat reaches at least 75°C with a thermometer, or it is piping hot all the way through, there is no pink left and the juices run clear
- Always follow the manufacturer's instructions when preparing food
- Boil imported frozen berries for one minute before eating them or adding them to smoothies. This is particularly important for vulnerable people like pregnant women, the elderly or those with compromising condition. Boiling imported frozen berries is needed because they have been associated with outbreaks of norovirus and hepatitis A across Europe in recent years.
- If you are showing symptoms (i.e., diarrhoea and vomiting) wash your hands fully and often. To avoid person to person spread, stay away from school or work (especially if you are a food handler) until a week or more after the symptoms have started.