Prevention not inactivation key to tackling foodborne viruses - EFSA

The European food safety watchdog said foodborne viruses are the second most common cause of outbreaks in the region – bested only by the ubiquitous Salmonella bug - and have been on the rise since 2007.

Figures from the agency’s Scientific Panel on Biological Hazards (BIOHAZ) showed that in 2009 viruses accounted for 1,000 outbreaks – 19 per cent of the total – in the European Union, resulting in 8,700 victims.

Prevention focus​

Viruses do not multiply on food, but products can act as a vehicle for transmittance to humans. The three most common foodborne viruses are norovirus (NoV), hepatitis A (HAV) and hepatitis E (HEV).

“Effective measures to control the spread of these viruses should focus on preventing contamination at all levels of production rather than on trying to remove or inactivate these viruses from contaminated food,”​ said the panel.

Contamination can occur during primary production or further processing and the experts recommended a raft of measures to prevent this from occurring – particularly in higher risk foods such as bivalve molluscs or fresh produce.

Bivalve molluscs – hazard-based controls​

For bivalve molluscs, they propose that a European standard for their classification and monitoring in terms of such factors as method and frequency be adopted across the region. At present this is not the case which can lead to “differential health outcomes”​ in different countries.

The flushing out of faecal decontaminates from molluscs could also be removed. Present operators use either depuration (flushing out with clean seawater in a tank) or relaying (an identical method but carried out in the natural environment.

The panel said these techniques as currently performed are “demonstrably not providing adequate levels of public health protection”.​ It urged that both methods be used and the process be monitored using polymerase chain reaction (PCR).

Food business operators could then be obliged to “determine the depuration and relaying operating procedures incorporated into their HACCP plans according to removal of human enteric viruses rather than E. coli.”​

It also suggests using a more sophisticated risk assessment system based on how intensely the molluscs are cooked and targeting testing according to areas where consumption is highest and where they are more usually eaten whole.

More robust methods for detecting NoVs and HAVs now mean it is feasible to implement hazard-based controls for viruses.

Fresh produce – microbiological criteria​

For fresh produce, the BIOHAZ members tabled the introduction of specific microbiological criteria for viruses.

As well as laying down EU legislation regarding the quality of irrigation water as well as adherence to the World Health Organisation’s guidelines on the safe use of waste-water, excreta and grey water.

The ability of viruses to survive food preservation methods such as chilling or acified or dry conditions – means “establishing microbial growth inhibition will not be sufficient to prevent foodborne viral infections”.​

It suggests using treatments such as irradiation or HPP or other decontamination techniques such as peracitic acid.

Hygiene of food handlers along the production, processing and packaging chain is also flagged up as key for fresh produce and ready-to-eat foods.

Meat products Meat or liver should also be subject to sufficient heat treatment to ensure that possible hepatitis E infections are removed or inactivated.

To read the full EFSA report click HERE​