Comparison of hydrostatic and hydrodynamic pressure to inactivate foodborne viruses

The effect of high hydrostatic pressure (HPP) and hydrodynamic pressure (HDP), in combination with chemical treatments, was evaluated for inactivation of foodborne viruses and non-pathogenic surrogates in a pork sausage product. Sausages were immersed in distilled water, 100-ppm EDTA, or 2% lactoferrin, and then inoculated with feline calicivirus (FCV), hepatitis A virus (HAV) or bacteriophage (MS2, phiX174, or T 4). Each piece was packaged individually and subjected to pressure by either HDP, HPP (500 MPa, 5 min, 4 °C), or control (no pressure). On sausages immersed in water, HPP and HDP significantly ( P < 0.05) reduced titers of FCV by 2.89 and 2.70 log 10 TCID 50/ml, and HAV by log 10 3.23 and 1.10, respectively, when compared to non-pressure-treated controls. Titers of T 4 (1.48 and 1.10 log 10 PFU/g) and MS2 (1.46 and 0.96 log 10 PFU/g) were also significantly reduced by HPP and HDP treatments, respectively, in combination with water. Inoculation of viruses and bacteriophage on a meat product may have protected viruses from complete inactivation by pressure treatments. This is the first study to directly compare hydrostatic and hydrodynamic pressure technologies to inactivate microorganisms. This is also the first study to examine the inactivation of viruses and bacteriophages by pressure technology in a deli meat product. This study shows that viruses attached to meat surfaces may be protected from complete inactivation by hydrostatic and hydrodynamic pressure treatments, and these findings require more investigation into the survival of viruses in deli meat products.