Frequently Asked Questions About Foodborne Viruses and Food Safety
Foodborne viruses such as norovirus and hepatitis A virus are among the leading causes of foodborne illness worldwide. This page answers common questions about foodborne viruses, their transmission, and practical approaches to managing risk in food industry settings.
Foodborne viruses are viruses that can be transmitted through contaminated food, water, or infected food handlers. The most important examples include norovirus and hepatitis A virus, which are leading causes of foodborne illness worldwide. Hepatitis E virus is also an emerging virus which mainly affects the pork and pork products supply chains.
Foodborne viruses are highly infectious and can cause illness even at very low doses. Unlike bacteria, they cannot grow in food, which means contamination typically occurs before consumption through infected handlers or contaminated raw products, including contaminated water e.g. irrigation water.
Norovirus is most commonly transmitted through food by infected food handlers who contaminate food during preparation. This can occur when proper hand hygiene is not followed after using the toilet, or when infected individuals continue working while symptomatic. Norovirus can also contaminate foods such as fresh produce through contaminated irrigation water, or shellfish harvested from contaminated waters. Because norovirus is highly infectious and environmentally stable, very low levels of contamination can be sufficient to cause illness.
Foodborne viruses differ from bacteria in several important ways. Viruses cannot grow or multiply in food, but they are highly infectious and can cause illness at very low doses. Transmission typically occurs through contaminated food handlers, contaminated water, or contaminated raw products rather than through bacterial growth in food. Viruses can also survive for long periods in the environment and are resistant to some common control measures. These characteristics mean that prevention focuses on hygiene, exclusion of ill food handlers, and control of contamination rather than preventing growth.
Foods most commonly associated with foodborne viruses include fresh produce such as berries, leafy greens, and salads, as well as shellfish such as oysters harvested from contaminated waters. These foods are often consumed raw or with minimal processing, which means viruses present on the food are not inactivated before consumption. Ready-to-eat foods handled after preparation and/or cooking also present a risk if contaminated by infected food handlers.
Control of foodborne viruses relies on preventing contamination and reducing viral contamination levels. Key measures include strict hand hygiene, exclusion of symptomatic food handlers, effective cleaning and disinfection, and ensuring safe sources of water and raw materials. For certain products, such as shellfish and pork liver, validated cooking processes can effectively inactivate viruses. Awareness of virus transmission routes and implementation of appropriate food safety management systems are essential to minimise the risk of foodborne virus transmission.
Foodborne viruses are a major cause of foodborne illness worldwide, but they are often not covered in detail in standard food safety training. Because viruses behave differently from bacteria and are transmitted through different routes, food safety professionals need specific knowledge to assess and manage these risks effectively. Specialist training helps improve awareness of transmission pathways, high-risk foods, and appropriate control measures, supporting more effective food safety management and risk reduction.