Effect of Processing Technologies to Control Viruses in Foods

Traditionally, processing technologies rely on the control of bacterial contaminants as a measure of their effectiveness. However, various studies have shown that some foodborne viruses are more resistant than vegetative bacteria to certain control mechanisms and thus may not be inactivated at the same rate as bacteria. In addition, as the food industry increasingly moves towards milder thermal processes, as well as the use of non-thermal technologies, the likelihood of viruses surviving such treatments increases. Therefore, validations of control strategies also need documented scientific evidence to demonstrate the effectiveness of control measures for reducing or eliminating viruses from foods. Validation approaches are hampered by the difficulty in cultivating enteric viruses. The replication assay recently developed for certain human norovirus strains should in the future allow evaluation of control strategies for these viruses. However, at present, the most common approach has been to use cultivable surrogate viruses such as Feline Calicivirus, Murine norovirus, Tulane virus and bacteriophages such as MS2. This presentation will give an overview on the efficiency of intrinsic and extrinsic factors of foods and various processing technologies, both traditional thermal and non-thermal technologies, and chemical based technologies to inactivate enteric viruses in foods. There are difficulties in comparing inactivation studies as numerous factors such as surrogate choice and its preparation, treatment time, inoculation methods and time allowed for inoculum to attach to the product could have a significant impact on the reduction observed. A standardised method for evaluating decontamination strategies for foods would be very useful for the food industry and future research needs to develop such as guidance will be discussed.