Title: Predictive thermal inactivation model for effects and interactions of temperature, NaCl, sodium pyrophosphate and sodium lactate on Listeria monocytogenes in ground beef Authors
Submitted to: Food and Bioprocess Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 23, 2013
Publication Date: April 18, 2013
Citation: Juneja, V.K., Mukhopadhyay, S., Marks, H.L., Mohr, T., Warning, A., Datta, A. 2013. Predictive thermal inactivation model for effects and interactions of temperature, NaCl, sodium pyrophosphate and sodium lactate on Listeria monocytogenes in ground beef. Food and Bioprocess Technology. DOI:10.1007/s11947-013-1102-z. Interpretive Summary: Listeria monocytogenes has been known as a human pathogen for over 80 years and causes over 1500 illnesses annually in the United States. Undercooked meat and meat products are commonly implicated as transmission vehicles in these outbreaks. We quantified a reduced heat treatment given to these foods to provide an adequate degree of protection against survival of the pathogen and developed a mathematical model for predicting the destruction of this pathogen in beef. The model can be used to predict the time required at any temperature to kill a certain number of bacteria. This information will be of immediate use to consumers and to the food industry and regulatory agencies to aid in the development of guidelines to ensure safety of the food supply.
Technical Abstract: The effects and interactions of heating temperature (60 to 73.9C), salt (0.0 to 4.5% w/v), sodium pyrophosphate (0.0 to 0.5% w/v), and sodium lactate (0.0 to 4.5% w/v) on the heat resistance of a four-strain mixture of Listeria monocytogenes in 75% lean ground beef were examined. Meat samples in sterile filtered stomacher bags were heated in a temperature controlled waterbath to determine thermal death times. The recovery medium was tryptic soy agar supplemented with 0.6% yeast extract and 1% sodium pyruvate. Weibull survival functions were employed to model the primary survival curves. Then, survival curve-specific estimated parameter values obtained from the Weibull model were used for determining a secondary model. The results indicate that temperature and salt have a large impact on the inactivation kinetics of L. monocytogenes, while sodium lactate (NaL) has an impact in the presence of salt. The model presented in this paper for predicting inactivation of L. monocytogenes can be used as an aid in designing lethality treatments meant to control the presence of this pathogen in ready-to eat products.