The systems involves two stages: (a) instantaneous heating of the lower surface upper film of the package before the film descends over the meat surface and (b) tight disposition of the plastic film on the meat surface in order to avoid wrinkles and purges.
This system showed higher quality (microbiological and physicochemical analysis) over VP with lower counts of aerobic mesophiles, anaerobes, and lactic acid bacteria (LAB). Lower pH values correlated with higher LAB counts, higher meat firmness, slower met tenderization, and higher luminosity, and redness. All these factors improved meat color (Barros-Velázquez et al. 2003)
VSP versus VP has been evaluated on several cuts from different anatomical parts of beef and on three spoilage bacterial groups (aerobic mesophiles, anaerobes, and coliforms) at 4 C for 40 days. It was observed that for all three groups VSP showed the highest inhibition on microbial growth. However, it seems that VSP has a slightly negative effect on the aging process, since tenderness is one of the most important quality attributes of meat (Vázquez et al. 2004).
ã€Source: Safety and Quality Effects in Foods Stored under Modified Atmosphere Conditions Juliana Morales-Castro and L. Araceli Ochoa-Martinez】