The European Food Safety Authority (EFSA) has been coordinating a trace-back investigation into a multinational outbreak of hepatitis A virus (HAV) genotype IA infection that has affected more than 1440 people in 12 European countries since January 2013.
To date, 331 cases in Denmark, Finland, France, Germany, Ireland, Norway, the Netherlands, Poland, Sweden and the UK have been confirmed by genotyping as being caused by the same outbreak strain. A large number of HAV infections have also been reported in Italy.
The outbreak investigation has established an epidemiological link with frozen berry products and HAV contamination was detected in frozen mixed berries and mixed berry cakes/pastries in Italy, France and Norway. Links between confirmed cases and suspect berries have also been identified in Ireland, the Netherlands and Sweden.
Tracing of 43 lots of frozen mixed berries has found that the most common ingredients were Bulgarian blackberries and Polish redcurrants, but no single point source of contamination was identified. It is thought that contamination could be occurring in primary production, or at the freezing processor. As contaminated berries may still be present in the food supply chain, further cases of infection may occur and consumers in some countries are being advised to boil imported frozen berries for one minute before consumption.
The EFSA trace-back investigation report can be found in full here.