The Hidden Risk in Our Food: Why Viruses Persist Despite Modern Safety Systems

Foodborne viruses such as norovirus, hepatitis A, and hepatitis E remain difficult to control because they spread through contaminated water, infected food handlers, and animal reservoirs, and they resist many standard food safety measures. The FAO–WHO experts conclude that prevention, safe water, sanitation, hygiene, and keeping sick workers away from food is far more effective than trying to remove or kill viruses after contamination.

When the Food and Agriculture Organization of the United Nations and the World Health Organization brought together scientists from Wageningen University & Research, Erasmus MC, the Swedish Food Agency’s EU Reference Laboratory for Foodborne Viruses, the U.S. Food and Drug Administration, Health Canada, Mahidol University, and public health institutes across the globe, they were tackling a quiet but stubborn problem. Foodborne viruses cause millions of illnesses every year, yet they remain far less understood and far harder to control than bacterial foodborne threats.

Unlike bacteria, viruses such as norovirus and hepatitis A do not grow in food. They get there through human contamination and then simply wait. Hepatitis E virus follows a different path, entering the food chain through infected pigs and wild game. What unites them is their ability to survive harsh conditions, resist common cleaning methods, and infect people at extremely low doses. The result is a global food safety challenge that standard controls often fail to contain.

Water: The Invisible Highway for Viruses

Water runs through nearly every part of the food system, and the report makes clear that it is also the main route for viral contamination. Shellfish filter large volumes of coastal water and concentrate whatever pathogens are present. Fruits and vegetables may be contaminated by irrigation water, pesticide sprays, or wash water used after harvest. As climate change and water scarcity push more countries toward wastewater reuse, the risks grow if treatment systems are not strong enough.

A key problem is that water safety rules usually rely on bacterial indicators. These bacteria are easier to measure, but they do not reliably signal whether viruses are present. As a result, food can meet legal standards and still carry infectious viruses, creating blind spots in even advanced food safety systems.

Shellfish and Produce: Clean on Paper, Risky in Reality

Shellfish show how these gaps play out in practice. For decades, producers have relied on depuration, holding shellfish in clean water so they purge contaminants. While this works well for bacteria, viruses often remain. Numerous outbreaks have been linked to shellfish that passed inspections but still carried norovirus. Relaying shellfish to cleaner waters for longer periods works better, but it is expensive, location-dependent, and still guided by imperfect indicators.

Fresh and frozen produce presents another challenge. Frozen berries, in particular, have been linked to large international outbreaks. Freezing preserves viruses, allowing contamination that happened on a farm or in a processing plant to cause illness months later in another country. Despite stronger hygiene rules, contamination events such as sewage leaks or poor sanitation during harvesting are hard to detect before products reach consumers.

The Human Factor in Ready-to-Eat Foods

In restaurants and food service settings, the biggest risk is not technology but people. The report confirms that infected food handlers are the main source of norovirus and hepatitis A virus in ready-to-eat foods. Even one sick worker can contaminate dozens of meals through poor hand hygiene, surface contact, or vomiting incidents.

Studies show that the most effective solution is also the simplest: keep sick workers away from food preparation. High compliance with exclusion policies sharply reduces illness. Cleaning surfaces and wearing gloves helps, but they cannot fully compensate for an infectious worker. Yet in many places, workers lack paid sick leave, making exclusion policies difficult to enforce.

Pork, Game, and a Virus That Starts on the Farm

Hepatitis E virus adds a different layer of complexity. It is common in pigs and wild game and has been found in pork livers, sausages, pâtés, and blood products sold at retail. Animals often show no signs of illness, so contamination goes unnoticed. Cooking can kill the virus, but it is more heat-resistant than expected, especially in fatty foods.

Several outbreaks have been linked to traditional dishes made with raw or lightly cooked pork liver. While labeling and public warnings have helped in some countries, changing long-standing food habits has proven difficult.

Prevention Beats Fixes, Every Time

The strongest message from the report is that prevention works better than any after-the-fact fix. Safe water, effective sanitation, good hygiene, and keeping sick workers out of food handling roles consistently reduce risk. High-tech solutions like advanced wastewater treatment, ultraviolet disinfection, and novel food processing methods show promise, but they are costly, unevenly available, and difficult to test fully.

In lower-income settings, simple measures, such as clean water access, toilets, and hygiene education, have delivered major public health gains. In wealthier countries, the challenge is not lack of knowledge but lack of consistency.

Foodborne viruses, the experts conclude, are not unstoppable. But controlling them requires treating food safety as more than a technical issue. It is a matter of infrastructure, labor policy, environmental protection, and public behavior. As food systems grow more global and water systems more stressed, ignoring viral risks is no longer an option.