Summary of FDA’s Strategy to Prevent Human Norovirus and Hepatitis A Outbreaks Associated with Fresh and Frozen Berries
FDA Prevention Strategies to Enhance Food Safety Main Page
Outbreaks of enteric virus infections, including hepatitis A virus (HAV) and norovirus (NoV) have been linked to fresh and frozen berries in the United States and globally. While no enteric virus outbreaks associated with domestic berries have been reported in 35 years, there have been reported outbreaks linked to imported fresh and frozen berries.
Contamination can be the result of lapses in food safety systems and prevention methods. Key factors to consider in preventing outbreaks include proper hygienic practices of field workers, management of sanitary facilities, measures to prevent cross-contamination of fruit in field and processing operations, and measures to monitor and limit viral carriage of farm and facility workers. Further investigation is needed to better understand viral persistence in the agricultural environment, the processing environment, and in berries; routes of contamination; and public health factors.
Overview of Intestinal Illness Linked to Consumed Berries
Enteric virus (HAV and NoV) outbreaks have been associated with fresh and frozen berries consumed in the United States. The most recent HAV outbreaks occurred in 2022 and 2023, in which imported berries from the same grower were identified as the vehicle. In 2023 a joint expert panel of Food and Agriculture Organizations of the United Nations and World Health Organization identified frozen berries contaminated with HAV and NoV as one of the virus-commodity pairs of “highest global public health burden” in its updated review of foodborne viruses and relevant food commodities of highest public health concern.
Outbreaks reported since 1997 have been linked to imported fresh and frozen berries. However, hygienic practices and challenges for the control of enteric viruses in berries and other hand-harvested produce apply globally.
Observations from outbreak investigations identified potential factors and gaps in food safety programs that were likely contributing factors to the contamination of fresh and frozen berries. Consultations with industry food safety experts identified areas of focus in understanding and managing enteric virus risk in berries.
HAV is a vaccine-preventable short-term infection that does not become chronic. People usually completely recover within several weeks. However, infections may lead to more severe health problems, including liver failure, in persons who are older or immunocompromised, have chronic liver disease, or have other underlying health conditions. Although anyone is vulnerable to HAV, the aforementioned groups of people are at higher risk of becoming infected and developing symptoms such as fatigue, nausea, vomiting, abdominal pain, jaundice, dark urine, and pale stool.
NoV in the United States, according to the Centers for Disease Control and Prevention (CDC). Most common settings for norovirus outbreaks are healthcare facilities, restaurants, catered events, schools, childcare centers, and cruise ships, food can become contaminated with norovirus at the source, including the farm.
The FDA developed a FDA Employee Health Policy Tool as part of Healthy People 2030’s norovirus workgroup initiative to reduce norovirus through retail activities.
Individuals can be infected and shed enteric virus particles before or without demonstrating symptoms, highlighting the importance of consistent application of sanitary controls.
Summary of FDA’s Strategy to Prevent Future Outbreaks of Human Hepatitis A and Human Norovirus Linked to Fresh and Frozen Berries
Food safety is a collaborative effort throughout the supply chain. Growers and processors have a responsibility to deliver safe produce in line with relevant food safety requirements. The identification and communication of effective food safety practices in fresh and frozen berry operations could benefit operators throughout the global berry industry and provide insight into effective controls for other fresh and frozen produce with similar risk factors.
Using information gained from outbreak findings, historical data, consultations with food safety experts in industry and other interest holders, the FDA has established goals and strategies to help prevent future outbreaks linked to consuming fresh or frozen berries.
This prevention strategy is designed to address factors that may contribute to the contamination of berries with enteric viruses. It outlines actions for the FDA, industry, and other interest holders to ensure accurate and timely communication and consistent application of effective prevention measures across the global berry industry. Significant efforts include:
- Promote high rates of compliance with FDA food safety requirements.
- Encourage the berry industry to identify and ensure consistent application of processes, or a combination of processes, which describe adequate berry pre- and post-harvest sanitary practices for domestic and global berry operations, including promoting the use of root cause analysis when failures are observed in food safety systems.
- Broaden scientific knowledge about the viability, persistence, detection, and mitigation of viruses in fresh and frozen berries, pre- and post-harvest environments, and agricultural water sources.
- Incentivize industry and governments to embrace the use of public health prevention measures through immunization programs to promote worker health.
Further, this strategy addresses critical knowledge gaps by fostering scientific research to enhance our ability to detect and characterize enteric viruses in various sample types and link sources of contamination using advanced laboratory methods. Research also focuses on understanding the ecology of enteric viruses in berry and other fresh produce operations. All defined goals and deliverables aim to reduce future incidences of foodborne illness linked to fresh and frozen berries.
“Collaboration between regulators, the global berry industry, and other interest holders has been critical for the development of this strategy. We look forward to on-going collaboration with all interest holders to ensure the success of this strategy, and others, for the prevention of foodborne illness," stated Conrad Choiniere, Director of the Office of Microbiological Food Safety at the FDA’s Human Food Program (HFP).