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Inactivation of Viruses and Bacteriophages as Models for Swine Hepatitis E Virus in Food Matrices

Emmoth, Eva, Rovira, Jordi, Rajkovic, Andreja, Corcuera, Elena, Wilches Pérez, Diego, Dergel, Irene, Ottoson, Jakob R., Widén, Frederik
Food and environmental virology 2017 v.9 no.1 pp. 20-34
Escherichia coli, Feline calicivirus, Hepatitis E virus, Norovirus, coliphages, decontamination, food contamination, food industry, food matrix, ham, high pressure treatment, lactic acid, light intensity, liver, mice, microbial contamination, microorganisms, models, risk, sausages, swine
Hepatitis E virus has been recognised as a food-borne virus hazard in pork products, due to its zoonotic properties. This risk can be reduced by adequate treatment of the food to inactivate food-borne viruses. We used a spectrum of viruses and bacteriophages to evaluate the effect of three food treatments: high pressure processing (HPP), lactic acid (LA) and intense light pulse (ILP) treatments. On swine liver at 400 MPa for 10 min, HPP gave log₁₀ reductions of ≥4.2, ≥5.0 and 3.4 for feline calicivirus (FCV) 2280, FCV wildtype (wt) and murine norovirus 1 (MNV 1), respectively. Escherichia coli coliphage ϕX174 displayed a lower reduction of 1.1, while Escherichia coli coliphage MS2 was unaffected. For ham at 600 MPa, the corresponding reductions were 4.1, 4.4, 2.9, 1.7 and 1.3 log₁₀. LA treatment at 2.2 M gave log₁₀ reductions in the viral spectrum of 0.29–2.1 for swine liver and 0.87–3.1 for ham, with ϕX174 and MNV 1, respectively, as the most stable microorganisms. The ILP treatment gave log₁₀ reductions of 1.6–2.8 for swine liver, 0.97–2.2 for ham and 1.3–2.3 for sausage, at 15–60 J cm⁻², with MS2 as the most stable microorganism. The HPP treatment gave significantly (p < 0.05) greater virus reduction on swine liver than ham for the viruses at equivalent pressure/time combinations. For ILP treatment, reductions on swine liver were significantly (p < 0.05) greater than on ham for all microorganisms. The results presented here could be used in assessments of different strategies to protect consumers against virus contamination and in advice to food producers. Conservative model indicators for the pathogenic viruses could be suggested.