The Effect of Film Permeability on the Storage Life and Microbiology of Vacuum‐packed meat

Joints of beef were stored in packaging films with oxygen permeabilities ranging from 0–920 ml/m 2 24 h/atm at 25 °C and 100% r.h. The storage life of the ‘vacuum‐packaged’ meat, as assessed by discolouration and the development of putrefactive odours, was inversely related to film permeability; the best results were obtained with meat which received ‘zero oxygen’ treatment. The growth rates and final counts of Pseudomonas spp. increased with increasing film permeability; the storage life of the meat corresponded with the time taken for the counts of the organism to reach ca. 10 6 /cm 2 for putrefactive odours to be produced. Although their growth rate was unaffected, the final counts of Brochothrix thermosphacta also increased with increasing film permeability. These results are discussed in terms of the influence of film permeability on the inhibitory effects of Lactobacillus spp., whose numbers were unaffected by the permeability of the film used, and the substrates in the meat available to the bacteria.