Hepatitis A virus and Food Safety
Hepatitis A virus is one of the most important causes of foodborne viral infection globally and has been responsible for numerous large outbreaks associated with contaminated food. Unlike norovirus, which primarily causes gastroenteritis, hepatitis A virus infects the liver and can result in more severe and prolonged illness.
Foodborne transmission occurs when food becomes contaminated with the virus at any point during primary production, harvesting, processing, or preparation. Ready to eat foods that receive no further processing before consumption present the highest risk.
Understanding how hepatitis A virus enters the food chain, and how contamination can be prevented, is essential for food businesses, regulators, and food safety professionals.
Why hepatitis A virus is important in food safety
Hepatitis A virus is transmitted via the faecal oral route and can spread through contaminated food and water. Infected individuals may shed the virus before symptoms appear, increasing the risk of unintentional contamination.
Key characteristics that make hepatitis A virus a significant food safety concern include:
- Ability to survive in the environment and on food surfaces
- Stability under refrigeration and freezing conditions
- Long incubation period, typically 2 to 6 weeks
- Association with large, international foodborne outbreaks
- Potential to cause severe illness, particularly in adults
Because of the long incubation period, outbreaks are often difficult to detect and trace, allowing contaminated products to be widely distributed before the source is identified.
How hepatitis A virus is transmitted through food
Foodborne transmission occurs when food becomes contaminated with faecal material containing the virus. This contamination may occur at several stages of the food chain.
Contaminated irrigation or processing water
Fresh produce may become contaminated if irrigation or washing water contains human sewage.
Infected food handlers
Food handlers who are infected, particularly those who are asymptomatic or in the early stages of infection, may contaminate ready to eat foods through hand contact.
Contaminated harvesting environments
Foods produced in areas with poor sanitation infrastructure are at increased risk of contamination.
Cross contamination during processing or preparation
Contaminated surfaces, equipment, or hands may transfer the virus to food.
Foods most commonly associated with hepatitis A virus
Hepatitis A virus is most often linked with ready to eat foods and foods that are minimally processed.
High risk foods include:
- Fresh berries such as strawberries and raspberries
- Frozen berries
- Dates and other dried fruits
- Leafy green vegetables
- Shellfish, particularly oysters
- Ready to eat foods handled after cooking
Frozen fruit has been associated with multiple large outbreaks in Europe, highlighting the ability of the virus to remain infectious under frozen conditions.
Hepatitis A outbreaks linked to food
Numerous foodborne outbreaks of hepatitis A virus have been linked to contaminated produce and shellfish.
Examples include:
- Frozen berry outbreaks affecting multiple European countries
- Outbreaks linked to imported dates
- Shellfish harvested from contaminated waters
- Ready to eat foods contaminated during preparation
These outbreaks can affect large numbers of people and may result in significant public health and economic consequences. Many cases involve hospitalisation.
Hepatitis A virus and HACCP
Hepatitis A virus must be considered within food safety management systems, particularly where ready to eat foods are produced or handled.
Critical control measures include:
- Strict food handler hygiene and illness exclusion policies
- Control of water quality used in irrigation and processing
- Supplier assurance and verification
- Prevention of cross contamination
- Implementation of effective HACCP systems
The FAO and WHO Joint Expert Meetings on Microbiological Risk Assessment (JEMRA) have published detailed guidance on prevention and control measures for foodborne viruses, including hepatitis A virus.
Recommendations emphasise the importance of prevention as the primary control strategy.
Why hepatitis A virus is difficult to control
Hepatitis A virus is highly stable and can persist in the environment and on foods for extended periods.
Challenges include:
- Survival under refrigeration and freezing
- Resistance to environmental stress
- Lack of visible signs of contamination
- Long incubation period delaying outbreak detection
Because contamination cannot be detected visually, prevention is essential.
Detection of hepatitis A virus in food
Detection requires specialised molecular methods such as RT PCR.
Testing is complex and requires:
- Careful sample preparation
- Efficient virus extraction
- Sensitive and specific molecular detection
Testing is usually performed during outbreak investigations, verification studies, or research. Routine testing of food is not widely used as a primary control measure. There are currently no regulations in place concerning the detection of hepatitis A virus in foods.
Prevention of foodborne hepatitis A virus
Effective prevention relies on multiple layers of control:
Food handler hygiene
- Strict hand washing procedures
- Exclusion of symptomatic staff
- Training and awareness
Control at primary production
- Use of clean irrigation water
- Protection from sewage contamination
- Good agricultural practices
Food business controls
- HACCP based food safety systems
- Supplier verification
- Environmental hygiene
Training and awareness
Training food handlers and food safety professionals is one of the most effective ways to reduce hepatitis A risk.
Foodborne virus training
Understanding how hepatitis A virus behaves differently from bacterial hazards is essential for effective control.
ViroSafety provides specialist training courses focused specifically on foodborne viruses, including norovirus, hepatitis A virus, and hepatitis E virus.
These courses are designed for:
- Food manufacturers
- Retailers
- Food service operators
- Environmental Health Officers
- Food safety professionals
Learn more about our foodborne virus training courses here: www.virosafety.co.uk
Frequently asked questions
Can hepatitis A virus be transmitted through food?
Yes. Hepatitis A virus is commonly transmitted through contaminated food, particularly ready to eat foods and fresh and frozen produce.
Which foods carry the highest risk?
Fresh and frozen berries, dates, shellfish, and ready to eat foods are most frequently associated with outbreaks.
Why is hepatitis A associated with frozen fruit?
The virus can survive freezing and remain infectious for long periods.
The virus can survive freezing and remain infectious for long periods.
How can food businesses reduce the risk?
Strict hygiene, safe water use, supplier control, and effective HACCP systems are essential.