Fact sheet on Hepatitis A viruses

General
The hepatitis A virus causes an acute inflammation of the liver with clinical signs of jaundice. Regarding food, transmission is possible particularly via raw foods, water and human excretors. In countries with low hygiene standards, seroprevalence in childhood is very high. In Europe and North America, hepatitis A cases now occur mainly in association with travel, which has led to a continuous decline in case numbers in recent decades.

Properties

• Viral pathogen

Origin / Occurrence

• Humans are the main host of hepatitis A viruses
• Occurs in countries with low hygiene standards. In Europe and North America, hepatitis A cases now occur mainly in association with travel
• Contaminated wastewater and drinking water as well as contaminated raw foods (e.g. shellfish, oysters, fruit (mostly frozen) and vegetables)

Significance

• Humans are the main host and probably the only reservoir of hepatitis A viruses. These are excreted in stool 1 to 2 weeks before onset of illness and are transmitted to people and food by direct contact or smear infections
• Characteristic for the virus is a high resistance to disinfectants, environmental influences and heat
• The number of foodborne hepatitis A infections in Germany is very low and predominantly travel-associated
• There is a vaccination recommendation by the Standing Committee on Vaccination (STIKO) for travellers to endemic areas

Clinical picture

• Low minimal infectious dose: approx. 10–100 viral particles
• Incubation period: 2 to 6 weeks
• Duration of illness: 3 to 6 weeks
• Symptoms: abdominal pain, joint and limb pain, flu-like symptoms, vomiting, nausea, associated with fever and an aversion to fatty and fried foods, jaundice (due to liver disease bile components enter the blood and cause yellowing of the eyes and skin)

Examples of affected foods

• Contaminated drinking water
• Contaminated seafood (e.g. shellfish, oysters)
• Vegetables, salad, fruit (due to fertilization of fields with feces or irrigation with fecally contaminated water)
• Foods contaminated with feces containing hepatitis A viruses

Stability

• Replication is only possible in host cells in humans
• In foods and drinking water viruses cannot replicate but can remain infectious for an extended period
• Temperature:
  • Optimum: +4 °C
  • Viruses can remain infectious for prolonged periods at refrigeration and freezing temperatures (-18 °C)
  • Increasing inactivation above +60 °C
• Sensitive to low pH values and dryness

Inactivation by heating

• At +85 °C for a minimum exposure time of 2 minutes the viruses are inactivated (Note: check core temperature)

1. Train employees regarding potential errors and corrective measures
2. Regular cleaning and disinfection of hands and regular glove changes
3. Regular change of work clothing. Ensure cleanliness of work clothing
4. Train employees on infection control requirements
5. Verification by visual on-site inspections and follow-up testing

Deficiencies in infection control:
This creates the risk of transmission of pathogenic microorganisms from people to product-contact surfaces or directly to food

Examples:

Salmonella from excretors or ill employees

Staphylococcus aureus from employees with inflamed or purulent wounds or with colonization of the nasopharynx

1. Employees who are ill with or suspected of infections by Salmonella, EHEC/STEC, Shigella, Vibrio cholerae, hepatitis A or E viruses or other infectious gastroenteritis, or who excrete the above-mentioned bacterial pathogens, must not work in food businesses handling highly perishable foods and in kitchens according to the Infection Protection Act (IfSG) (see IfSG § 42)
2. The same applies to employees with inflamed or purulent wounds. Non-infected wounds must be dressed hygienically
3. Regular training/instruction of employees regarding the required infection control measures
4. Verification by visual on-site inspections, checks of training records and follow-up testing

1. Distance from fields with livestock; keep wild animals away from fields using e.g. fences or nets
2. Water hygiene: contaminated water must not be used for irrigation. Irrigation and drainage systems must be suitable. Regular monitoring of microbiological water quality
3. No use of microbially contaminated fertilizers in crop production
4. Personnel & work hygiene during harvest or downstream steps
5. Remove soil/contaminants by washing
6. Verification by follow-up testing

1. Inspect products at goods receipt for e.g. incoming/transport temperature, shelf life, packaging, deviations or abnormalities
2. The same applies to goods before use in production. In case of doubt, do not use the food and ask a supervisor
3. Check microbiological specifications. If necessary, arrange laboratory testing of suspicious products or request results from the supplier
4. Verification by follow-up testing

1. Review work organization in the facility
   1. Separate work areas, equipment and utensils for raw and processed foods
   2. Separation of "clean" and "unclean" areas and activities
2. Train employees regarding potential errors and corrective measures
3. Verification by visual on-site inspections and follow-up testing

1. Check processes, production protocols and documentation
2. Inactivation of the viruses at a core temperature of +85 °C for a minimum of 2 minutes
3. Check correctness of processes and temperatures
   1. Generally, hot-holding temperatures above +60 °C are required
   2. Rapid cooling: after 3 hours a core temperature of at least +7 °C must be reached (special caution is required for large quantities)
4. Verification by follow-up testing