Prevalence of Rotavirus, Bovine Enteric Calicivirus and F-RNA Coliphages on Commercial Vacuum Packaged Beef

Introduction: There are concerns about the potential zoonotic transmission of animal strains of norovirus (bovine enteric calicivirus, BEC), and rotavirus (RV). F-RNA coliphages, part of the gut flora and likely to be deposited on meat along with other enteric organisms during carcass dressing and processing, may be regarded as an indicator and/or surrogate for potential zoonotic enteric viruses. In addition, F-RNA coliphages can be genotyped to differentiate human (genogroups II and III) from animal sources (genogroups I and IV).

Purpose: The objective was to determine the numbers of F-RNA coliphages, BEC and RV on commercial vacuum packaged beef in Canada during the summer and winter months and perform molecular characterization of the isolates.

Methods: The entire surface of each sub-primal, purchased from retail stores, was swabbed with a sponge and viruses were dislodged from the sponges with a stomacher. Infectious F-RNA coliphages were detected by plaque assay. RNA was extracted from clarified and concentrated (ultrafiltration) supernatant and F-RNA coliphage, BEC and RV RNA were detected by real time RT-qPCR.

Results: Infectious F-RNA coliphages were recovered from 46/140 cuts at levels ranging from 0.26-80 plaque forming units/100 cm²where 24 samples were positive for F-RNA coliphages of human origin(1 GII and 23 GIII)  and 24 were positive for F-RNA coliphages of animal origin (24 GI and 1GIV) while 4 samples contained genotypes of both human and animal origin.  RV was detected in 6 samples by molecular detection while BEC was not detected. F-RNA GI was detected in only 1 sample by qRT-PCR 

Significance: The low levels of infectious F-RNA coliphages are below the limit of detection by qRT-PCR in most instances. About 4% of samples were positive for RV. In addition, contamination by food handlers may be a concern as 50% of the positive samples were associated with F-RNA coliphages of human origin.