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United States Department of Agriculture

Agricultural Research Service

Research Project: MICROBIAL MODELING AND BIOINFORMATICS FOR FOOD SAFETY AND SECURITY

Location: Residue Chemistry and Predictive Microbiology

Title: The effects of salt, sodium pyrophosphate and sodium lactate on the probability of growth of Escherichia coli O157:H7 in ground beef

Authors
item Hwang, Cheng-An
item Juneja, Vijay

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 9, 2010
Publication Date: April 1, 2011
Citation: Hwang, C., Juneja, V.K. 2011. The effects of salt, sodium pyrophosphate and sodium lactate on the probability of growth of Escherichia coli O157:H7 in ground beef. Journal of Food Protection. 74(4):622-626.

Interpretive Summary: Ground beef products are susceptible to contamination with Escherichia coli O157:H7. This study examined the effect of salt (0-2.25%), sodium pyrophosphate (SPP, 0-0.5%) and sodium lactate (0-3%) on the growth of E. coli O157:H7 in vacuum-packaged ground beef after storage for 15 days at 10 degree centigrade. A total of 25 combinations of the three additives were examined. A model was developed to describe the probability of growth of E. coli O157:H7 in ground beef as affected by salt, SPP and lactate concentrations. The model indicated that lactate decreased the growth probability of E. coli O157:H7 in ground beef, and the effect was enhanced by higher salt concentrations. This study demonstrated the effect of salt, SPP and lactate on the probability of growth of E. coli O157:H7 in ground beef, and may be used by the producers to identify the levels of salt, SPP and lactate and/or additional hurdles needed to control E. coli O157:H7 in ground beef products.

Technical Abstract: Ground beef products are susceptible contamination with Escherichia coli O157:H7. The objective of this study was to examine the effect of salt, sodium pyrophosphate (SPP) and sodium lactate on the probability of growth of E. coli O157:H7 in ground beef after storage for 15 days at 10 degree centigrade. Ground beef containing 0-2.25% salt, 0-0.5% SPP and 0-3% lactate was inoculated with a 4-strain mixture of E. coli O157:H7, vacuum-packaged and stored at 10 degree centigrade for 15 days. A total of 25 combinations of the three additives, each with 20 samples, were tested. A logistic regression was used to model the probability of growth of E. coli O157:H7 (with a 1.5-log CFU/g increase during storage) as a function of salt, SPP and lactate. The resulted probabilistic model indicated that lactate at higher concentrations decreased the probability of growth of E. coli O157:H7 in ground beef, and the effect was more pronounced at higher salt concentrations. At salt concentrations below 1.3%, the increase of SPP concentration increased the growth probabilities of E. coli O157:H7, whereas at higher salt concentrations, the increase of SPP concentration decreased the probability. The probabilistic model demonstrated the effect of salt, SPP and lactate on the probabilities of growth of E. coli O157:H7 in ground beef, and will be used to identify the levels of salt, SPP and lactate and/or additional hurdles needed to control E. coli O157:H7 in ground beef products.

Last Modified: 7/31/2014
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