The Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO) Joint Expert Meeting on Microbiological Risk Assessment (JEMRA) has published a report on control measures for foodborne viruses.

The report is a continuation of JEMRA’s work to review recent scientific developments, data, and evidence associated with foodborne viruses. As part of this work, in December 2024, JEMRA published a report ranking the most important foodborne viruses and virus-food commodity pairings, which identified human norovirus as the leading cause of foodborne illness, especially associated with prepared foods, frozen berries, and shellfish. Hepatitis A virus contamination of shellfish, frozen berries, and prepared foods and hepatitis E virus contamination of pork and wild game were also identified as virus–commodity pairs of concern.

The newly published report on prevention and intervention measures for foodborne viruses focused on the virus–commodity pairs of concern identified in the first report.

JEMRA concluded that, in the last 16 years, awareness of the public health importance of foodborne virus-commodity pairs of concern has increased, resulting in additions or changes to some food supply chain management strategies and research initiatives. Prevention remains the cornerstone of control, as the foodborne viruses of concern are environmentally persistent and resistant to many treatments commonly used to inactivate foodborne pathogens.

The report outlined contamination routes, prevention strategies and virus inactivation methods for commodities of concern.

Shellfish

Fecal pollution in growing waters is the primary route of viral contamination. Sanitary surveys to evaluate fecal contamination status can inform safe shellfish harvesting. The use of male-specific coliphages to assist in evaluating the efficacy of depuration and relaying processes shows promise. More effective tertiary wastewater treatment can reduce viral load in effluent but requires infrastructure investment. Climate change is anticipated to result in heavier rainfall in some locations, which may increase the likelihood of sewage overflows or runoff.

Contaminated products are either discarded or diverted to processing (depuration, relaying, heat, or high-pressure). Depuration does not always adequately remove or inactivate viruses from contaminated products. For diverted product, thermal processing at very high internal temperatures (90 seconds at more than 90 °C) can inactivate viruses but may ruin the product; emerging data indicates that other time-temperature combinations can lead to the same outcome. High-pressure processing (HPP) can be effective but may affect organoleptic properties.

Fresh and Frozen Produce

Sewage sludge, fecally impacted source waters (used for irrigation, washing, pesticides, and frost protection), and infected food handlers (pickers/packers) are the most prominent sources of viral contamination for fresh and frozen produce. Frozen berries are the most significant produce commodity associated with virus outbreaks due to freezing preserving virus infectivity and resulting in global distribution and extended shelf-life.

In the last 16 years, virus prevention during produce production and processing has been included in Good Agricultural Practices (GAPs), Good Manufacturing Practices (GMPs) and Good Hygiene Practices (GHPs). Specific production-related intervention strategies should focus on water source, location, method, and timing of application. Emerging treatments of water (e.g., ozone, photocatalysis, ultraviolet, and ultrafiltration) show potential but require infrastructure investment. Biochar filtration is a relatively inexpensive method that shows promise for treating reused water.

Most fresh berries are not washed post-harvest. Washing other produce items (e.g., lettuce and green onions) with water alone removes less than 1 log₁₀ foodborne viral pathogens. The addition of low concentrations of chlorine-based disinfectants (e.g., hypochlorite and chlorine dioxide) can boost efficacy but may come with regulatory and organoleptic concerns. For produce diverted to thermal processing, commercial sterilization (e.g., jams and jellies) should result in inactivation of viruses. Standard juice pasteurization conditions should provide some inactivation, but longer times and/or higher temperatures may be needed to eliminate heat-resistant strains. Novel and emerging food processing techniques have been investigated, but none currently have a strong enough body of evidence to justify their routine use.

Prepared and RTE Foods 

In the case of norovirus and hepatitis A virus, prepared and ready-to-eat (RTE) foods are usually contaminated through infected food handlers. Prevention focuses on exclusion of infected food handlers from work, glove-wearing, surface disinfection, and adequate personal hygiene, including handwashing. Facilities should be equipped with handwashing stations and toilets to encourage good personal hygiene. Although many countries have policies guiding foodservice appropriate employee behaviors (e.g., personal hygiene, exclusion of sick workers) and most countries actively promote handwashing, compliance is generally poor. In response to findings that noroviruses are shed and aerosolized in vomiting events, formalized guidelines for clean-up and disinfection after vomiting or defecation incidents in foodservice have been implemented.

For maximum effectiveness of chemical-based surface disinfection, surfaces should be cleaned first. Guidelines for norovirus disinfection using free chlorine vary by country. Most commercial disinfectants and hand sanitizers, used under manufacturer recommended conditions, provide only partial inactivation of norovirus. There is significant variability in product performance based on active substance(s) and formulation.

Pork and Wild Game Meat

Zoonotically transmitted hepatitis E virus enters the food chain by infection of pigs and wild game animals. Human exposure occurs through the consumption of raw or inadequately cooked meats and tissues, direct contact with infected animals on farms and in slaughterhouses (surface cross-contamination), or use of untreated pig manures or runoff from farms. Recent studies have proposed that control measures should focus on prevention of animal infection at the preharvest phase (i.e., biosecurity measures and disinfection) and post-harvest interventions (i.e., preventing cross-contamination, virus inactivation by heat, and avoiding the use of high-risk tissues in product formulations).

In meat, hepatitis E virus is highly resistant to heat. For example, it was reported that it took 20 minutes in a pâté-like product to obtain the similar inactivation as was observed for a relatively pure virus suspension treated at the same temperature (70–72 °C) for 2 minutes. Omitting the use of high-risk contaminated tissues (liver or blood) in raw or undercooked pork products can also reduce transmission risk from foods.

Data Gaps and Future Research

An overarching problem identified throughout the literature is the limited ability to routinely cultivate wild-type foodborne viruses in the laboratory, which complicates the ability to validate interventions, compare studies, or interpret monitoring data.

In future research, it may be beneficial to explore early identification of contamination hotspots (e.g., wastewater surveillance) as a control tool, as well as the use of technologies like satellite imagery and hydrographic dye studies to predict virus dispersion in waterways. Emerging scientific data should be used to develop surface disinfectant and hand sanitizer formulations with greater efficacy against environmentally stable viruses.