viral agEnts in food: thE ovErlookEd risk

Nearly each week a new foodborne outbreak linked to viruses is reported in the media. These food poisoning cases usually implicate norovirus (NoV) or hepatitis A virus (HAV) such as when dried tomatoes were contaminated with HAV in France 2010 with 59 people affected.1 In the same timeframe three other hepatitis A outbreaks were associated with eating semi-dried tomatoes: in Australia in 2009 and in the Netherlands in 2010. In the European Union (EU), viral agents were responsible for 11.9% of the foodborne outbreaks reported to the European Food Safety Authority (EFSA) during 2007 and were identified as the second most common causative agent group, after Salmonella.2
undEtECtEd viral infECtions
Foodborne viral infections differ from bacterial infections.

Unlike bacteria, once present in food, viruses will neither modify the taste nor the aspect of the product so viral infections often go undetected. Numerous foodborne outbreaks caused by viruses have been seen in the world. There are estimated to be 9.2 million foodborne illnesses related to Norovirus in the US each year. In 2008, 19 member states of the EU reported a total of 697 outbreaks. For those outbreaks that were verified, noroviruses were the most frequent cause, followed by HAV.

Viruses can be very infectious. Norovirus inoculums as low as ten viral particles may be sufficient to infect an individual, leading to very high excretion of viruses in stool for several weeks. Enteric viruses, like hepatitis A virus and norovirus, can survive for long periods
in food and water. Generally viruses
are more resistant to chemical and UV disinfection, filtration and pasteurization than microorganisms. However, viruses may be removed by ultrafiltration membranes or inactivated by prolonged heating or optimal UV treatment. In general, viruses will survive reasonably well in adverse conditions, microbial proteolysis and fermentation. As they are resistant to several food processes, consumption of these processed food products may lead to new human outbreaks. Additionally, infected people may also represent a risk as a great number of foodborne outbreaks are linked to food handlers.
1 Hepatitis A Associated with Semidried Tomatoes
rEgulatory stEps takEn
To help overcome the risks associated with food-borne viruses, regulatory officials have and continue to pursue several measures:
European Commission Regulation (EC) No 2073/2005 of 15 November 2005 indicates that “Foodstuffs should not contain micro-organisms or their toxins or metabolites
in quantities that present an unacceptable risk for human health”, underlining that methods are required for foodborne virus detection.
This year, an expert working group created by the European Committee for Standardization (CEN), is expected to publish a standard method for the detection of norovirus and hepatitis A virus in food products (shellfish, fruits and vegetables, surfaces and bottled water). The standard method will include qualitative and a quantitative measures.
The CODEX Committee on Food Hygiene (CCFH) is working on a guideline for the application of general principles of food hygiene for the control of viruses in food, which is now ready for final adoption.
EFSA published a report in 2011
on “scientific opinion on an update on the present knowledge on the occurrence and control of food-borne viruses”.
Food may be contaminated by viruses during all stages of the food supply chain, and transmission may occur by
2 EU Summary Report on Food-Borne Outbreaks
consumption of food contaminated during the production process (primary production, or during further processing), or contaminated by infected food handlers. Viruses do not multiply in foods, but may persist for extended periods of time as infectious particles
in foods. Therefore, the EFSA panel recommends focusing controls on preventive measures to avoid viral contamination rather than trying to remove or inactivate viruses from food.
gEt thE bEst support availablE
Foodborne viruses are no longer emerging but constitute a real
concern to the safety of food. To help organizations meet diverse regulation requirements and to support their internal risk assessment studies, SGS has implemented analytical methods based on the expected standard method from CEN.
As validated methods are available for many types of food and environmental samples, SGS can offer analytical services to food companies. Our services will help food companies
to measure viral risks and integrate foodborne virus testing in their analytical surveillance plans.
Find out more about SGS Food Safety Solutions.
Ron Wacker, PhD
Global Business Development Manager Food Testing
SGS Germany
ron.wacker@sgs.com
t +49 6039 4696540