A Refinement of an International Standard Method (ISO/TS 15216–2:2013) to Allow Extraction and Concentration of Human Enteric Viruses from Tissues of Edible Snail Species

Abstract

In the recent years, a revival in interest in snail meat consumption has promoted a rapid development of snail farming systems to cover an increasing consumer demand and to protect the free-living snail population. Snail meat, like other types of food intended for human consumption, should be free from any microbiological hazards before being placed on the market. Snail meat may contain bacteria, but little is known about the possibility of contamination with human enteric viruses. Therefore, to test snail tissues for viruses, a suitable virus detection method is needed. Up to now, many methods for virus extraction and concentration from molluscan shellfish have been published, but only one has been adopted as an international standard procedure. In this study, a refinement of an ISO method (ISO/TS 15216–2:2013) was conducted to make it suitable for processing of edible snail tissues. The digestive glands from three edible snail species (Helix pomatia, Cornu aspersum maxima, Cornu aspersum aspersum) were used as samples, and method performance was assessed on the basis of murine norovirus RNA detection in spiked samples using a one-step real-time reverse transcription-PCR. The mean percentage of virus recovery from tissues of C. a. maxima was 5.71 %, 0.31 % for C. a. aspersum and 1.28 % for edible snail. As demonstrated here, this method was successfully applied for virus detection in snail samples, and its use can be recommended in monitoring of snails for virus contamination.