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A comparison of proteinase K and PEG<sub>8000</sub> on the recovery of calicivirus and norovirus in artificially contaminated food

Tibollo, S., Zoni, R., Mariani, E., Zanelli, R., Colucci, M.E., Sansebastiano, G.E.
Quality assurance and safety of crops & foods 2014 v.7 no.2 pp. 153-158
Feline calicivirus, Norovirus, food contamination, food matrix, foods, peptidase K, protocols, quality control, rapid methods, raspberries, virion, viruses, water pollution
Noroviruses (NoV), transmitted mainly through the faecal-oral route, are particularly infectious and only a few particles carried by contaminated water or food are needed to cause the disease. In particular raspberries are often the cause of the onset of an outbreak. These viruses may cause large-scale outbreaks that could be limited if there was a rapid detection of the source of infection. The aim of this study is to compare the results of a method for viral detection in foodstuffs using proteinase K, a serine protease, with one that uses PEG<sub>8000</sub> in order to assess which one provides the highest viral recovery. Mixed berries were artificially contaminated with a viral solution – feline calicivirus (FCV) or NoV – and they were analysed with the two methods for the elution of viral particles. In tests with FCV the method with proteinase K was able to obtain recovery percentages on average about three times higher than with PEG<sub>8000</sub> (68.297 vs. 23.989). The difference between the two recoveries is statistically significant, whereas in tests with NoV, even if the protocol with proteinase K provided the best results the gap between the two methods isn't statistically significant. The proteinase K protocol obtained better recoveries in tests with both FCV and NoV. This method has the potential to become the official standard technique for the detection of viruses in food matrices.