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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Microbial and Chemical Food Safety » Research » Publications at this Location » Publication #385047
Research Project: Development of Predictive Microbial Models for Food Safety using Alternate Approaches

Location: Microbial and Chemical Food Safety

Title: Growth and no-growth boundary of Listeria monocytogenes in beef – A logistic modeling

Author
item Huang, Lihan
item JIA, ZHEN - Fujian Agriculture And Forest University
item Hwang, Cheng An

Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2021
Publication Date: 12/23/2021
Citation: Huang, L., Jia, Z., Hwang, C. 2021. Growth and no-growth boundary of Listeria monocytogenes in beef – A logistic modeling. Food Research International. 152. https://doi.org/10.1016/j.foodres.2021.110919.
DOI: https://doi.org/10.1016/j.foodres.2021.110919

Interpretive Summary: Listeria monocytogenes is a major food safety hazard. A “zero-tolerance” is maintained by the USDA FSIS to protect consumers. This study attempts to establish the growth and no-growth boundary of L. monocytogenes in ready-to-eat (RTE) products by developing a multi-factor logistic regression model, which may be used by the food industry to properly formulate RTE products with a combination of control factors, such as sodium tripolyphosphate, sodium lactate, sodium diacetate, sodium chloride, sodium nitrite, and pH, to prevent the growth of L. monocytogenes even under the optimum temperature. The results of this research may enhance the safety of the food supply if used by the food industry.

Technical Abstract: Listeria monocytogenes is a potentially fatal foodborne pathogen. Its growth in ready-to-eat (RTE) foods must be strictly controlled to protect public food safety. This study was conducted to define the growth and no-growth boundary of L. monocytogenes with sodium tripolyphosphate (STPP), sodium lactate (NaL), sodium diacetate (NaDiAc), sodium chloride (NaCl), sodium nitrite (NaNO2), and pH as control factors. The growth of L. monocytogenes was examined using a solid medium incubated under 37°C for 48 h in 96-well microtiter plates. NaNO2 (1,800 ppm) and NaDiAc (2,500 ppm) were found not effective in preventing the growth when applied alone. STPP was shown highly effective in preventing the growth of L. monocytogenes. Its growth was unhindered at pH 6-7 but was gradually decreased beyond the neutral range. High concentrations of NaL and NaCl were needed to inhibit the growth of L. monocytogenes. A logistic regression model was developed to define the growth and no-growth boundary of L. monocytogenes for the combined effect of all six factors. The results showed that the logistic regression model was reasonably accurate in determining the growth probability and boundary of L. monocytogenes, with a success rate of 68.6%, false positive rate of 14%, and false negative rate of 17.4% in PALCAM agar. The model was validated in ground beef, with or without pH adjusted with tomato paste. The success rate for predicting the growth of L. monocytogenes in ground beef was 85%, with false positive and negative rates at 10 and 5%, respectively. With a stringent criterion for defining the growth/no-growth boundary, the results of this study may be used by the food industry to formulate RTE products that do not allow the growth of L. monocytogenes even stored under the optimum temperature.