Modeling for the inhibition of CO2 combined with probiotic on Listeria monocytogenes in pork

Abstract:

[Background] The pork safety problem caused by Listeria monocytogenes not only brings great consumption risks to consumers but also causes huge economic losses to the food processing industry. The virulence of Listeria monocytogenes in pork products should be controlled to curb the occurrence of public health events.[Objective] To explore the inhibitory effect of CO₂ combined with the probiotic Lactobacillus plantarum (CO₂-LP) on L. monocytogenes in pork by the method of predictive microbiology and determine the optimal combination of CO₂-LP. [Methods] The Jameson-effect model was employed to establish the growth curves of L. monocytogenes in pork samples treated with CO₂-LP, and the kinetic parameters including lag phase (λ), maximal growth rate (μ_max), and maximum population density (N_max) were determined. [Results] The inhibitory effect of CO₂-LP was well fitted by the Jameson-effect model. CO₂-LP treatment prolonged the λ and reduced the μ_max and N_max of L. monocytogenes. Moreover, the inhibitory effect of CO₂-LP enhanced as the CO₂ concentration increased. Compared with the control group, the 80% CO₂-LP treatment increased the λ by 0.87 fold and decreased the μ_maxand N_max by 47% and 2.05 lg (CFU/g), respectively. Although 80% CO₂-LP had the best inhibitory effect, the 60% CO₂-LP was selected as the optimal treatment, because the presence of N₂ could prevent pack collapse in modified atmosphere packaging. Compared with the control group, 60% CO₂-LP treatment increased the λ by 0.81 fold and decreased the μ_maxand N_maxby 33% and 1.83 lg (CFU/g), respectively.[Conclusion] CO₂-LP treatment inhibited the growth of L. monocytogenes in pork from different aspects, which reflected the advantages of hurdle technology.

Key words:CO₂;probiotic;combination;model of inhibition;Listeria monocytogenes