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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Residue Chemistry and Predictive Microbiology Research » Research » Publications at this Location » Publication #352364

Research Project: Development of Predictive Microbial Models for Food Safety using Alternate Approaches

Location: Residue Chemistry and Predictive Microbiology Research

Title: Thermal resistance of listeria monocytogenes and Enterococcus faecium unsalted and 10% salted liquid egg yolk

Author
item Huang, Lihan

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2019
Publication Date: 5/22/2019
Citation: Huang, L. 2019. Thermal resistance of listeria monocytogenes and Enterococcus faecium unsalted and 10% salted liquid egg yolk. Journal of Food Safety. Available:https://onlinelibrary.wiley.com/doi/10.1111/jfs.12665.
DOI: https://doi.org/10.1111/jfs.12665

Interpretive Summary: Listeria monocytogenes is a major foodborne pathogen that may contaminate liquid egg yolk (LEY). Enterococcus faecium is a bacterium found in pasteurized LEY. This study was conducted to investigate the thermal resistance of L. monocytogenes and E. faecium in both unsalted and 10% salted LEY. Kinetic models were developed to assess the thermal resistance of these microorganisms. The models may be used to design adequate heating conditions to inactivate L. monocytogenes and E. faecium in LEY.

Technical Abstract: Listeria monocytogenes is a major foodborne pathogen that may contaminate liquid egg yolk (LEY). Enterococcus faecium is a bacterium found in pasteurized LEY. This study was conducted to investigate the thermal resistance of L. monocytogenes and E. faecium in both unsalted and 10% salted LEY. Samples were treated isothermally at temperatures between 55 and 67.5C. Both Weibull model and linear survival model were used to analyze the survival curves. Data analysis showed that the thermal resistance of E. faecium was not affected by the addition of 10% salt in LEY, and was in almost 2 orders in magnitude higher than that of L. monocytogenes in unsalted LEY. Adding 10% salt to LEY significantly elevated the thermal resistance of L. monocytogenes to the level of E. faecium. It can be concluded that the heating conditions used to inactivate L. monocytogenes or Salmonella Enteritidis would not be able to kill E. faecium if it is found in unsalted LEY, while similar heating conditions can be used to kill both L. monocytogenes and E. faecium in 10% salted LEY. The results of this study may be used to design adequate heating conditions to inactivate L. monocytogenes and E. faecium in LEY.