Establishment of growth probability model for Pseudomonas spp. in chilled pork with modified atmosphere package

In order to extend the shelf life of chilled pock and to provide reference for the choice of atmosphere package, this study simulated the real production, and established the growth probability model of Pseudomonas spp. in chilled pork with atmosphere modified packaged at (4±1)℃. Logistic model was used to establish the growth/non-growth boundary of Pseudomonas spp. in different percentage of CO2. The disinfected pock was inoculated with Pseudomonas spp., which is one kind of specific spoilage organisms of the chilled pock. The results indicated that without CO2 or with low percentage of CO2, the growth probability of Pseudomonas spp. increased with the increase of percentage of O2 or the initial inoculation. With high percentage of CO2, the growth probability of Pseudomonas spp. was low, and not sensitive to the percentage of O2, and initial inoculation. The Logistic model performed well, which determination coefficient (r2) of the model was higher than 0.85, the determination coefficient (R2) of observed data and predicted data were all higher than 0.95, and the predicted accuracy was higher than 93.3%. Four predicted conditions of the probability model were defined as "effective-safe", "effective-dangerous", "ineffective-safe", "ineffective-dangerous" in this paper, which were used to evaluate the validity of the model and to ensure the safe choice of the atmosphere condition. The results can provide technological references for the choice of atmosphere condition in the chilled pock production.