The findings of the Clemson University researchers were published in the journal, Food Microbiology.
The researchers claim that combining in-package pasteurization with natural antimicrobial components is a novel approach to food preservation and has a greater impact on bacterial populations compared to interventions using a single treatment, reducing the need for intense heat treatment.
“Results from this study could have a significant impact for the industry since a reduction in bacterial contamination was achieved by a relatively short pasteurization time and antimicrobials reduced populations further during refrigerated storage,” said the research team.
Goals: To evaluate the efficacy of surface application of nisin, a natural GRAS antimicrobial with FDA approval and/or lysozyme, derived from hen egg white. The substances were tested in combination with in-package pasteurization of RTE low fat turkey bologna against L. monocytogenes and salmonella. “Application of additional hurdles to control the growth of these organisms would provide an increased margin of safety during refrigerated storage,” claim the researchers.
Method: RTE low fat turkey bologna averaging 14.3 per cent fat, 10.7 per cent protein, and 71.4 per cent moisture with 2 per cent salt was used for the experiment, according to the study. The sterile bologna samples were treated with solutions of nisin, lysozyme, and a mixture of the two antimicrobials before in-package pasteurization at 65°C, claim the researchers.
Results: The researchers said the in-package pasteurization resulted in an immediate 3.5 to 4.2 log reduction in L. monocytogenes for all treatments and that all pasteurized treatments also resulted in significant reduction of the pathogen by 12 weeks compared to un-pasteurized bologna.
In-package pasteurization allied with nisin-lysozyme treatments was effective in reducing the bacterial population below detectable levels after two-three weeks of storage. This result complies with USDA requirements for RTE and poultry products in order to suppress or limit the growth of the pathogen during storage.
Aporte: Claudia Henríquez P.