How Norovirus and Hepatitis-A Can Linger in Frozen Berries

Berries are a delicious and versatile fruit, but their journey from farm to table comes with a real risk of contamination. While fresh and frozen berries are a healthy snack, they’ve been linked to food borne illnesses caused by resilient viruses. In response, the FDA has introduced new strategies to reduce these risks (1^✔ ✔Trusted Source
Summary of FDA's Strategy to Prevent Human Norovirus and Hepatitis A Outbreaks Associated with Fresh and Frozen Berries

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Why Are Berries at Risk of Contamination?

Berries are often hand-picked and handled extensively during harvesting, which increases the potential for contamination. Workers might not always have access to adequate hygiene facilities or training, and this can result in the transfer of harmful viruses like norovirus and hepatitis A to the berries.

Key factors contributing to berry contamination include:

• Human Handling: Many berries are hand-harvested, which raises the chances of contamination if proper hygiene isn’t practiced.
• Resilience of Viruses: Norovirus and hepatitis A can survive on berries even after freezing or minimal processing.
• Challenges in Washing: Berries are delicate and difficult to wash thoroughly without damaging them, leaving traces of contaminants behind.
• Global Supply Chains: Imported berries are particularly vulnerable due to varying safety standards and hygiene practices in different countries.

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Viruses Most Commonly Found in Berries

Two major viruses that have been linked to berry contamination are norovirus and hepatitis A. These viruses are resilient and can persist in environments where they are hard to detect and eliminate.

Norovirus

• Symptoms: Causes vomiting, diarrhea, stomach cramps, and nausea.
• Spread: Often transmitted through contaminated food or water and spreads rapidly in group settings like schools, restaurants, and cruise ships.
• Resilience: Freezing doesn’t kill norovirus, making frozen berries a common vehicle for its spread.

Hepatitis A

• Symptoms: Affects the liver, causing fatigue, abdominal pain, nausea, vomiting, jaundice (yellowing of skin and eyes), and dark urine.
• Risks: Although a vaccine is available, older adults, immunocompromised individuals, and those with chronic liver diseases are at higher risk of severe complications.
• Spread: Like norovirus, it can be transmitted by infected individuals who don’t practice proper hygiene during food handling.

Why Frozen Berries Are More Vulnerable

Frozen berries have been identified as having the “highest global public health burden” for transmitting viruses like norovirus and hepatitis A. Freezing preserves the viruses rather than killing them, making the fruit infectious upon consumption.

In recent years, several outbreaks have been traced to imported frozen berries. For example, hepatitis A outbreaks in 2022 and 2023 were linked to frozen berries from the same grower. While domestic fresh berries haven’t been linked to outbreaks in decades, imported fresh and frozen berries continue to pose risks due to differing food safety regulations and practices.

How to Reduce the Risk of Contamination

Although contamination risks can’t be eliminated entirely, consumers can take proactive steps to reduce exposure to viruses. Here’s how you can protect yourself and your family:

• Don’t eat berries straight out of the package but wash berries thoroughly
• Use fruit sanitizers with solutions containing peroxyacetic acid or hydrogen peroxide
• Opt for domestic berries
• Practice proper storage in a clean, dry container in the refrigerator or freezer to minimize the risk of cross-contamination.

FDA’s New Strategy to Protect Consumers

To address the risks associated with contaminated berries, the FDA launched a comprehensive prevention strategy. This plan aims to reduce outbreaks caused by viruses in fresh and frozen berries through several measures:

• Promoting Compliance with Food Safety Standards by Ensuring growers and processors follow rigorous food safety practices.
• Enhancing Scientific Knowledge by Studying virus persistence and mitigation in berry production environments.
• Encouraging Worker Vaccinations by Supporting immunization programs for farmworkers to prevent the spread of hepatitis A.
• Enhancing Collaboration by Engaging with the global berry industry to implement consistent safety measures and address gaps in food safety systems.

Berries are a delicious and nutritious addition to any diet, but their vulnerability to contamination with resilient viruses like norovirus and hepatitis A highlights the need for caution. The FDA’s new strategy marks a significant step toward improving safety standards, but individual actions like proper washing and choosing trusted sources also play a crucial role. With these precautions, you can continue to enjoy your favorite berries while keeping food borne illnesses at bay.

Reference:

1. Summary of FDA’s Strategy to Prevent Human Norovirus and Hepatitis A Outbreaks Associated with Fresh and Frozen Berries - (https://www.fda.gov/food/new-era-smarter-food-safety/summary-fdas-strategy-prevent-human-norovirus-and-hepatitis-outbreaks-associated-fresh-and-frozen)

Source-Medindia