Tenacity (resistance) of noroviruses in strawberry compote - BfR opinion No. 038/2012, 6 October 2012

On 19 September 2012, what has so far been the largest known foodborne outbreak of gastroenteritis in Germany broke out in various schools and childcare establishments in the federal states of Berlin, Brandenburg, Saxony, Saxony-Anhalt and Thuringia. A total of more than 11,000 children and youths suffered from diarrhoea and vomiting. Epidemiological studies conducted by the Robert Koch Institute and the task force set up at the Federal Office of Consumer Protection and Food Safety suggest that the pathogen and / or the pathogenic substance were transmitted through a batch of raw deep-frozen strawberries. Results from stool tests show that norovirus may have been the cause of the illness. The Federal Institute for Risk Assessment (BfR) has evaluated the tenacity, i.e. the resistance of noroviruses in strawberry compote which was produced in various ways in the kitchens implicated in the outbreak. Little is generally known about the tenacity of the human norovirus, because the infectiousness of these viruses cannot be measured due to a lack of cell culture systems. Nevertheless, according to the current state of knowledge, it is to be assumed that a high risk of infection is posed not only by raw but also by briefly heated dishes made from strawberries, if they are contaminated with noroviruses.