Correlations between growth parameters of spoilage micro-organisms and shelf-life of pork stored under air and modified atmosphere at −2, 4 and 10 °C

The correlations of the growth parameters (the initial cell number (N0), maximum cell number (Nmax), maximum specific growth rate (μmax), lag-phase (λ)) of typical spoilage micro-organisms (lactic acid bacteria (LAB), coliforms, pseudomonads, Brochothrix thermosphacta) growing on sliced pork to the sensory shelf-life and microbial shelf-life were investigated. The changes in sensory quality and proliferation of micro-organisms on pork shoulder were studied at different atmosphere conditions (air and 40%CO2/59%N2/1%O2) and temperatures (−2, 4 and 10 °C). Microbial counts were fitted to the modified-Gompertz equation to obtain the growth parameters of different micro-organisms. B. thermosphacta and coliforms were predominant bacteria associated with spoilage of pork under all temperatures and air conditions. However, pseudomonads could only dominate under regular atmosphere condition. Using multiple linear regression, high correlations were found between the lag-time (λ) of LAB (0.9814, 0.9830), B. thermosphacta (0.9895, 0.9849), or the maximum specific growth rate (μmax) of coliforms (−0.9583, −0.9695) and the microbial shelf-life and sensory shelf-life, respectively. The μmax and λ of micro-organisms correlated well with microbial and sensory shelf-life. The shelf-life of pork is mainly correlated with the growth parameters of μmax and λ than by Nmax.