Virus inactivation - evaluation of treatment processes for food and biowaste

Sammanfattning: Animal by-products and manure contain valuable plant nutrients that could be recycled onto arable land, as fertiliser. If these materials contain pathogenic microorganisms, such as viruses, transmission to domestic animals, wildlife and the food chain could occur. Virus contamination of food may further occur during all production phases, from slaughter to packaging and distribution. To reduce virus hazards, control measures such as physical and chemical treatments could be applied. As many important food-borne viruses are non-culturable, model viruses are often used to evaluate the effect of virus inactivation methods. As models for swine hepatitis E virus (HEV) in food treatments, feline calicivirus, murine norovirus and bacteriophages were evaluated. MS2 and ø6 were used as models for highly pathogenic avian influenza virus (HPAIV) in ammonia inactivation and composting of animal by-products, respectively. In laboratory scale, controlling the factors considered to be the most important for virus inactivation, reduction of relevant and model viruses was assessed as a function of these factors. Recommendations regarding continuously measurable process conditions that should be kept over a certain time to reach sufficient viral reductions could be given, both for normal conditions and in an out-break situation. Bacteriophages could further be used as potential indicators for verification or validation in pilot or full scale processes. Regimes to assure a 3 log10 reduction for Category 3 materials (2011/142/EC) for ammonia and heat treatment were determined. Further protocols based on pH and temperature to be kept during a certain time for management of HPAIV in outbreak situations were provided based on statistical evaluations of the laboratory results. In high pressure treatment of pork products, pressure and time were defined as critical control points for feline calicivirus and murine norovirus, used as models for HEV. MS2 and ø6 were successfully used for verification of ammonia treatment and composting, respectively, in larger scale. In food treatments, MS2 was the most conservative indicator of noro and calicivirus inactivation in high pressure and intense light pulse treatments, and øX174 in lactic acid treatments, with potential as models for these types of viruses for verification in production scale.

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