Inhibitor‐Assisted High‐Pressure Inactivation of Bacteria in Skim Milk

• Autores: Hai‐bin Liu, Ping Li, Chang Sun, Xin‐jun Du, Yan Zhang, Shuo Wang
• Localización: Journal of food science, ISSN 0022-1147, Vol. 82, Nº 7, 2017, págs. 1672-1681
• Idioma: inglés
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• Resumen

  • The combined inactivation effects of high hydrostatic pressure (HHP) and antimicrobial compounds (potassium sorbate and ε‐polylysine [ε‐PL]) on 4 different bacterial strains present in skim milk and the effect of these treatments on milk quality were investigated in this study. HHP treatment at 500 MPa for 5 min reduced the populations of Escherichia coli, Salmonella entericaTyphimurium, Listeria monocytogenes, and Staphylococcus aureusfrom 6.5 log colony‐forming units (CFUs) or higher to less than 1 log CFU/mL. Compared to HHP alone, HHP with potassium or ε‐PL resulted in significantly higher reductions in the bacterial counts. After 5 min of treatment with HHP (500 MPa) and ε‐PL (2 mg/mL), no growth of E. coli, S. entericaTyphimurium, or L. monocytogenesin skim milk was observed during 15 d of refrigerated storage (4 ± 1 °C). Scanning electron microscopy analysis revealed that the synergistic treatments caused more serious damage to the bacterial cell walls. Quality assessments of the treated samples indicated that the combined treatments did not influence the color, the turbidity, the concentrations of –SH group of the proteins, or the in vitrodigestion patterns of the milk. This study demonstrates that HHP with potassium or ε‐PL may be useful in the processing of milk or milk‐containing foods. High hydrostatic pressure (HHP) processing is a nonthermal treatment but causes only sublethal injures to most microorganisms, which can later regrow during storage. HHP combined with food additives may cause microbial cell collapse and achieve greater food safety.