UPDATED: Potential Hep A contamination of fruit – experts respond

The Ministry for Primary Industries is warning consumers there is a small chance that fruit from a Hawkes Bay packhouse may have been contaminated with the Hepatitis A virus.

peachesIn media statement issued yesterday, MPI Deputy Director General Scott Gallacher reassured consumers that the  risk of transmission of the virus is relatively low, but MPI is issuing the information as a precaution so that people with any related concerns about their health can contact their doctor.

“We have been advised that a person packing some varieties of apples and peaches in a Hawke’s Bay packhouse has been diagnosed with Hepatitis A.”  Mr Gallacher said.

“This worker handled Royal Gala and New Zealand Beauty apples and Golden Queen peaches over a four day period while they would have been infectious. Hepatitis A virus can remain infectious on the surface of fruit for some months and transmit infection to other handlers and consumers.”

While some potentially affected fruit has been traced and withdrawn from sale, it is expected that approximately 1400 cartons have been sold, with fruit either consumed or still in some people’s homes.

Details of the fruit concerned, and where it may have been sold can be found in the MPI statement.

Symptoms  of Hepatitis A include: skin jaundice (yellowish tinge), yellowing of the whites of eyes, dark coloured urine and pale bowel motions. Early signs of Hepatitis A are fever, loss of appetite, stomach pains and nausea. MPI is Contact your doctor if you have these symptoms – particularly jaundice. If you are concerned about your health or the health of others, seek advice from your medical practitioner, or you can call the Healthline (0800 611 116) or PlunketLine (0800 933 922).

The SMC collected the following expert commentary. Feel free to use these quotes in your reporting. If you would like to contact a New Zealand expert, please contact the SMC (04 499 5476; smc@sciencemediacentre.co.nz):

Dr Gail Greening,  Science Leader/Consultant,  Environmental and Food Virology Laboratory, ESR, comments:

“Hepatitis A is a severe food and waterborne disease mainly transmitted by the faecal – oral route and caused by hepatitis A virus (HAV). It was previously known as infectious hepatitis or jaundice. The disease has an incubation period of two to six weeks with an average of 28 days.  Initially the symptoms are non-specific and include fever, headache, fatigue, anorexia, dark urine, light stools, and nausea and vomiting with occasional diarrhoea. The long incubation period means that it is often difficult to link the disease with a particular food product.

“Hepatitis A virus is very stable, showing high resistance to chemical and physical agents such as drying, heat, low pH, disinfectants and solvents and has been shown to survive in the environment, including seawater and marine sediments, for over three months.  Under refrigeration and freezing conditions the virus remains intact and infectious for several years.   It is also resistant to drying and shows high resistance to low humidity. 

“Hepatitis A virus has been associated with many outbreaks of foodborne disease. Contamination generally occurs either pre-harvest or during food handling.  Pre-harvest contamination of fruits and vegetables, including strawberries, raspberries, blueberries, lettuce, semi-dried tomatoes and green onions, has been reported and has resulted in outbreaks of disease in countries such as Finland, the Netherlands, the United States, Australia and New Zealand, where populations have low or no immunity to the disease.  The source of contamination in these outbreaks was reported to be infected produce harvesters, food handlers or contaminated irrigation waters. Since HAV is shed before symptoms appear and >106 infectious virus particles can be excreted per gram of faeces, HAV-infected produce-harvesters and food handlers, without knowing, can become a source of contamination.

“Following recent Australian outbreaks linked to HAV contamination of semi-dried tomatoes (SDT), HAV survival on fresh and semi-dried tomato surfaces was investigated by ESR. Results showed that inactivation of HAV on SDT using chemicals or heat was difficult and that the virus could retain infectivity at both room temperature and at 5oC for periods beyond the shelf life of the product. In an earlier study, ESR found that after storage at 4°C for 15 days no decline in hepatitis A virus levels was observed on strawberries and that the virus was not completely removed from the strawberries by washing with either cold or warm water.”

References are available on request.

Prof Michael Baker,  Department of Public Health, University of Otago, Wellington, comments:

“For older children and adults, hepatitis A is a very unpleasant illness that lasts from a few weeks to a few months.  It typically starts with fever, weakness, loss of appetite, and nausea, followed a few days later by jaundice.  About a third of cases are hospitalized.  Deaths are uncommon.  However, illness is more severe in older adults where the case fatality may be 1 to 2%. 

“Hepatitis A is now an uncommon infection in New Zealand with typically 50-100 notified cases a year.  Number vary considerably from year to year because of small local outbreaks. In most years, about half of the cases are acquired overseas, often by New Zealanders going on holiday or to visit friends and relatives.

“Transmission of hepatitis A is by the ‘faecal-oral’ route. Humans are the only important reservoir of hepatitis A, so infection is acquired from other people. It has a long incubation period (28-30 days).  The virus is excreted in faeces, so that becomes the source of infection for other people. Excretion in faeces takes place for 1-2 weeks before the case becomes symptomatic so an infectious food handler can potentially contaminate a lot of food before it is apparent that they are ill.  Similarly, young children often have asymptomatic infection, so can infect other children and adults without this being detected until one of those infected develops symptomatic illness.  These features of the disease make it difficult to prevent small outbreaks, particularly those that are linked to infected people coming from overseas.

“Hepatitis A outbreaks have been linked to contaminated fruit and vegetables in New Zealand and overseas. In 2002 New Zealand had an outbreak of at least 20 cases from consumption of contaminated raw blueberries. The outbreak was linked to a single commercial orchard. Hepatitis A virus was detected in blueberry product from the orchard which had been distributed across the country.  It was likely that the orchard was contaminated by infected food handlers or polluted groundwater.

“Preventing such outbreaks depends on multiple approaches throughout the food harvesting, production and distribution chain. In the case of hepatitis A, it is important to consider the health status of those involved in handling food that is sold and consumed raw, notably fruit and vegetables.  Hepatitis A vaccination is highly effective and could be considered for such occupational groups.”