Hepatitis is inflammation of the liver that is often caused by viral infections. There are several different viruses that can cause hepatitis, known as hepatitis A, B, C, D, and E viruses. These different types of hepatitis viruses can be transmitted in different ways, including through contaminated food and water.
Hepatitis A and E
Hepatitis A and hepatitis E viruses are commonly spread through contaminated food or water. This typically occurs when food handlers who are infected don’t properly wash their hands after using the bathroom and then contaminate the food or water supply. Hepatitis A and E are spread through what is known as the fecal-oral route – when tiny amounts of infected fecal matter from one person enters the mouth of another person.
Here are some of the most common foods that can carry hepatitis A and E viruses and lead to infection:
- Raw or undercooked shellfish and mollusks like oysters, mussels, and clams that come from contaminated water
- Unwashed fresh fruits and vegetables that have been contaminated during handling or harvesting
- Ready-to-eat foods like salads, sandwiches, ice, cookies, and boxed lunches that have been handled by an infected food worker
- Unpasteurized milk and dairy products
- Unpasteurized or undercooked eggs
- Undercooked meats
- Contaminated water used for drinking, making ice, cleaning fruits/vegetables, etc.
Hepatitis A and E can spread easily in areas with poor sanitation and inadequate handwashing. Major outbreaks often occur in developing countries where sanitation conditions and access to clean water are limited. Even in developed countries like the U.S., sporadic cases and smaller outbreaks can occur if contaminated items are imported from areas with high hepatitis rates.
Hepatitis B and C
Unlike hepatitis A and E, hepatitis B and C are not typically transmitted through contaminated food or water. Hepatitis B and C usually spread through contact with infected blood or bodily fluids. This includes:
- Sexual contact with an infected person
- Sharing needles or other injection equipment
- Needlestick injuries in healthcare workers
- Blood transfusions (now rare due to blood testing)
- Being born to an infected mother
It is possible, though rare, for hepatitis B and C to potentially be passed on through food. This could occur if an infected food handler bleeding from an open wound contaminates the food. Proper food handling techniques, like wearing gloves and keeping wounds covered, minimize this risk.
There are no known cases of hepatitis C spreading through food or water. But there have been some instances of hepatitis B transmission through food contaminated with infected blood. Overall, both hepatitis B and C have very low risk of spreading through contaminated food.
Hepatitis D
Hepatitis D can only occur in combination with hepatitis B infection. It is caused by the hepatitis D virus, which is an incomplete virus that requires the helper function of hepatitis B to replicate. Hepatitis D (also known as delta hepatitis) is transmitted the same way as hepatitis B – through contact with infected blood and body fluids. Contaminated food is not a source of infection.
How do contaminated foods transmit hepatitis viruses?
Hepatitis A and E viruses often contaminate food and water supplies when infected individuals handle food items with unwashed hands after using the bathroom. Microscopic amounts of fecal matter from the individual can be enough to transmit the virus to others if ingested.
Shellfish such as oysters pose a particular risk because they are often eaten raw or undercooked. Growing waters can become contaminated with sewage runoff containing hepatitis viruses. The shellfish filter and concentrate the viruses, leading to very high viral loads when consumed raw.
Fruits, vegetables, ready-to-eat foods, milk, and ice can also be contaminated if handled by a food worker who has hepatitis A or E. The viruses are relatively stable and can survive for weeks in the environment under optimal conditions. Refrigeration can allow viruses to persist even longer.
In rare cases, hepatitis B virus can contaminate food if it comes into contact with infected blood. This could occur from an infected food handler bleeding into the food. But hepatitis B is sensitive to heat, so cooking contaminated items eliminates the risk of transmission.
What are the symptoms of hepatitis?
Symptoms of hepatitis can include:
- Fever and chills
- Fatigue and weakness
- Loss of appetite
- Nausea, vomiting, and diarrhea
- Abdominal pain
- Dark urine
- Pale or clay-colored stools
- Joint pain
- Jaundice (yellow skin and eyes)
Symptoms can start anywhere from 2-8 weeks after exposure for hepatitis A, E, and B. Hepatitis C symptoms may not appear for 6-7 weeks. Some people, especially children, may have no symptoms with hepatitis infection.
How long can hepatitis viruses survive on food?
Hepatitis A virus can survive on foods and surfaces at room temperature for months unless inactivated by cooking or disinfection. Studies have found hepatitis A can persist:
- Over 30 days on fresh fruits, vegetables, and herbs
- Over 60 days in water and shellfish
- Over 90 days on frozen strawberries
- Over 120 days in blueberries kept at room temperature
Proper refrigeration and cooking can shorten these survival times. But hepatitis A virus can still persist for weeks at refrigeration temps. Heating foods to 185°F (85°C) for at least 1 minute reliably inactivates the virus.
Hepatitis E virus can persist for weeks to months on produce and in water. It also survives freezing. Heat inactivation requires heating to 194°F (90°C) for 3 minutes.
Hepatitis B virus can survive for over a week on surfaces at room temperature. It is less stable than hepatitis A and E. Cooking food to 140°F (60°C) for over 30 minutes inactivates hepatitis B virus.
Are there vaccines for hepatitis viruses?
Safe and effective vaccines are available to prevent infection from hepatitis A and B viruses:
- Hepatitis A vaccine – Given as 2 doses spaced 6-12 months apart. Recommended for all children age 12-23 months. Adults at increased risk should also be immunized.
- Hepatitis B vaccine – Given as 3 doses over 6 months. Now included in routine childhood immunization schedules.
There is currently no hepatitis C vaccine available. But research is ongoing to try to develop one. Hepatitis E vaccines have been developed and are licensed in China, but are not yet available in the U.S.
How can hepatitis be prevented from contaminated food?
To reduce the risk of hepatitis transmission from contaminated food:
- Wash hands thoroughly with soap and water after using the bathroom and before handling food
- Cook shellfish (oysters, clams, mussels) thoroughly before eating
- Wash fruits and vegetables, especially if eating raw
- Do not use contaminated water to wash produce or make ice
- Avoid cross-contaminating foods by keeping raw and cooked foods separated
- Cook foods thoroughly, especially meats, eggs, and seafood
- Avoid foods and beverages of unknown purity in developing areas
- Get vaccinated for hepatitis A and B if at increased risk
Proper food safety practices in commercial establishments and by food handlers are critical to prevent hepatitis viruses from spreading through contaminated food and water.
| Virus Type | Transmission Routes | Foodborne Risk | Inactivation |
|---|---|---|---|
| Hepatitis A | Fecal-oral route | High risk | Heating to 185°F (85°C) for 1 minute |
| Hepatitis E | Fecal-oral route | High risk | Heating to 194°F (90°C) for 3 minutes |
| Hepatitis B | Blood and body fluids | Low risk | Heating to 140°F (60°C) for 30+ minutes |
| Hepatitis C | Blood and body fluids | No known risk | Not foodborne |
| Hepatitis D | Blood and body fluids | No risk | Not foodborne |
Summary
Hepatitis A and E viruses are frequently transmitted through contaminated food and water. Raw or undercooked shellfish, produce, eggs, dairy, and ready-to-eat items pose the highest risks if handled by an infected person. Hepatitis B can rarely spread through food contaminated with blood. Hepatitis C is not known to spread through food. Proper hygiene, cooking temperatures, and avoiding high-risk items can prevent hepatitis infections from contaminated food and water sources.