Methods
In UK Food Hygiene Regulations there are currently no requirements to test food samples for viruses for the purpose of Official Control, and therefore no Official Reference method is specified.
However current best practise for virus testing involves use of the appropriate part of ISO 15216 (ISO 15216-1:2017 “Microbiology of the food chain — Horizontal method for determination of hepatitis A virus and norovirus using real-time RT-PCR — Part 1: Method for quantification” and ISO 15216-2:2019 “Microbiology of the food chain — Horizontal method for determination of hepatitis A virus and norovirus using real-time RT-PCR — Part 2: Method for detection”).
The two parts of the method cover quantification of and presence/absence testing for viruses respectively, in soft fruit, leaf, stem and bulb vegetables, bottled water, bivalve molluscan shellfish, and surfaces.
The UK NRL has produced a series of matrix specific generic protocols conforming to the requirements of ISO 15216, to assist testing laboratories in the practical implementation of ISO 15216. These are:
- Quantification of norovirus and hepatitis A virus in bivalve molluscan shellfish
- Quantification of norovirus and hepatitis A virus in soft fruit
- Detection of norovirus and hepatitis A virus on surfaces
In addition, the UK NRL has produced matrix-specific calculation spreadsheets to assist testing laboratories in quantification of samples and the determination of control results, for samples following ISO 15216-1, or the relevant UK NRL generic protocol. These are: