Research and consumer advice recommended on foodborne viruses

The Advisory Committee on the Microbiological Safety of Food (ACMSF) assessed the risk from viruses believed to be the primary cause of foodborne illness​.

The group said a better understanding of foodborne viral disease is required by investigating correlation between infective dose and genome titre.

It also recommended developing the methods used to assess norovirus and hepatitis E infectivity in food samples.

Surveillance and investigation​

Improved surveillance and investigation of foodborne viruses is required with government agencies developing a single outbreak reporting scheme, said the report.

An approach that would involve annual consolidation of records to reduce the underreporting outbreaks is needed, it added.

The report said there is a need for clear advice for consumers, for example on cooking shellfish and pork products and information on washing leafy green vegetables and soft fruit.

Technologies such as whole genome sequencing (WGS) and metagenomics for viruses may provide further insight into burden of foodborne infection and environmental routes of contamination.

ACMSF is a scientific advisory committee that provides the FSA with independent expert advice. It set up a group to revisit the issue of foodborne viruses after developments since its latest report.

The most important viruses associated with foodborne infection are norovirus, hepatitis A virus (HAV) and hepatitis E virus (HEV).

Norovirus and Hepatitis​

Norovirus is often associated with outbreaks linked to shellfish consumption, such as oysters or contaminated produce, or to soft fruits, particularly frozen.

The most commonly recognised outbreaks of foodborne norovirus cases are thought to result from contamination by infected food handlers but the proportion transmitted by food is still uncertain.

It is estimated that it causes around 200,000 cases of foodborne illness in England and Wales each year (Adak et al 2005).

ACMSF said the burden of HEV transmitted by food, including pork and pork products, is also not clear, although likely to be significant.

In England and Wales there are 300-700 clinical cases of Hepatitis E annually.

“With the emerging risk of hepatitis E in pigs, the group recommends work is undertaken to investigate the heat inactivation of hepatitis E in ‘pork products’.” ​

A review of data on food contact surface contamination, including survivability and persistence was considered along with options for control at all stages of the food chain e.g. thermal processing, storage.

Professor Sarah O’Brien, chair of the ACMSF, said until recently it was difficult to assess accurately the impact of foodborne viruses on public health.

“However, significant advances in our ability to detect viruses in food, coupled with up- to-date estimates of the burden of illness, highlighted in the ACMSF’s latest update, show us that viruses are very important, preventable causes of foodborne illness.”​

ACMSF published a report on foodborne viral infections in 1998.

At a March 2010 meeting, members agreed an Ad Hoc Group should be set up to revisit the issue because of significant developments, so an updated risk profile could be produced based on findings.

The results from the Second Infectious Intestinal Disease (IID2) Study (Food Standards Agency, 2012) provided further data on contribution of viruses to the burden in the UK.

Data identified norovirus, sapovirus and rotavirus as being the most common viruses found in samples from those with intestinal disease.