The Hepatitis A virus (HAV) is a non-enveloped, single stranded RNA virus that is classified in the Picornaviridae family. HAV is a liver disease that results from exposure to virus particles. The virus is primarily spread via the fecal-oral route—when an uninfected person ingests water or food that is contaminated with the feces of an infected person. HAV can be spread through contaminated water, inadequate sanitation, or poor personal hygiene by food handlers.
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Severity of illness from HAV can range from a mild illness lasting a few weeks to a severe illness lasting several months. Symptoms of Hepatitis A include: fever, fatigue, abdominal discomfort, nausea and vomiting, joint pain, loss of appetite, jaundice, clay-colored bowel, and dark urine.
According to the World Health Organization, HAV is one of the most frequent causes of foodborne infection, with a yearly estimate of 1.4 million cases worldwide. The largest foodborne outbreak of HAV occurred in Shanghai in 1998, affecting 300,000 people. The source of that outbreak was determined to be clams harvested from sewage-polluted waters.
The most common sources of foodborne HAV contamination are oysters, mussels, fruits, and vegetables. Fresh produce, such as salad, strawberries, raspberries, blueberries, and vegetables, have increasingly been implicated in foodborne outbreaks of Hepatitis A.
Individuals who have not been vaccinated or previously infected are at risk to contract HAV. In developed countries, such as the U.S., good sanitation and hygiene conditions keep HAV infection rates low. However, in developing countries, HAV is endemic and a majority of infections occur during childhood. Once infected with the virus, individuals develop antibodies to the virus, resulting in a lifelong immunity from contracting HAV again.
Hepatitis A in foods is a result of fecal contamination. Individuals infected with HAV excrete large numbers of virus particles in their feces, which may continue for several months even after symptoms have subsided. The long duration of virus particle shedding is the main source of spreading HAV via the fecal-oral route or through water contaminated with sewage.
Foodborne contamination with HAV typically occurs when the produce is grown in a region of the world where there is a high incidence of Hepatitis A. Any food that is handled using poor hygienic practices or harvested under poor sanitation conditions could potentially become contaminated.
Any food that is handled using poor hygienic practices or harvested under poor sanitation conditions could potentially become contaminated.
Fruits and vegetables are typically consumed raw and can become contaminated with fecal matter at any point during the growing, harvesting, packing, or serving of fresh produce. Therefore the regions of the world where produce is grown as well as potentially infected food handlers with poor hygiene practices can be potential sources of foodborne HAV contamination.
In the last decade, documented HAV outbreaks have been linked to lettuce, strawberries, blueberries, raspberries, and green onions. Since 2012, frozen berries have been linked to several outbreaks in Europe, totaling 601 cases with three deaths. It was also linked to frozen berries in the U.S. In 2013, pomegranate seeds from Turkey were linked to an outbreak that affected 159 people.
As recently as February of this year, a HAV outbreak occurred in Australia affecting at least 14 people. Once again, frozen berries were identified as the most likely source of the contamination. The implicated product contained raspberries that were packed in China; however, the exact source of the contamination has not yet been identified.
Strategies designed to reduce or prevent the risk of foodborne outbreaks of Hepatitis A should focus on preventing foods from becoming contaminated during growing, harvesting, and packaging. In developing countries, clean water should be used for the irrigation, washing, and processing of produce.