|Hwang, Cheng-an - Andy|
|Altuntas, Evrim Gunes|
Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2013
Publication Date: 6/5/2013
Citation: Juneja, V.K., Hwang, C., Sheen, S., Friedman, M., Altuntas, E., Ayhan, K. 2013. Predictive model for the reduction of heat resistance of Listeria monocytogenes in ground beef by the combined effect of sodium chloride and apple polyphenols . International Journal of Food Microbiology. 164:54-59. Interpretive Summary: Listeria monocytogenes continues to be a significant threat to the safety of ready-to-eat foods. This emphasizes the need to better define and quantify the heat treatment given to meat to provide an adequate degree of protection against survival of this pathogen. We 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 guard against the pathogen in foods.
Technical Abstract: We investigated the combined effect of three internal temperatures (57.5, 60, and 62.5C) and different concentrations (0 to 3.0 wt/wt %) of sodium chloride (NaCl) and apple polyphenols (APP), individually and in combination, on the heat-resistance of a five-strain cocktail of Listeria monocytogenes in ground beef. A complete factorial design (3 x 4 x 4) was used to assess the effects and interactions of heating temperature, NaCl, and APP. A total of 48 variable combinations were replicated two times and 96 bacterial survivor curves were obtained from the experimental data. Mathematical models were then used to quantitate the combined effect of these parameters on heat resistance of the pathogen. The theoretical analysis shows that compared with heat alone, the addition of NaCl enhanced and that of APP reduced the heat resistance of L. monocytogenes measured as D values. By contrast, the protective effect of NaCl against thermal inactivation of the pathogen was dramatically overcome by both additives, as evidenced by reduction of up to 68% in D-values at 57.5C; 65% at 60C; and 25% at 62.5C. The influence of the combined effect allows a reduction of the temperature of heat treatments as well as the salt content of the meat. Meat processors can use the predictive model to design processing times and temperatures that can protect against adverse effects of contaminated meat products. Additional benefits include reduced salt content of processed meat products, reduced energy use in cooking, and the potential for consumers to receive the reported beneficial health effects of antioxidative apple polyphenols.