Prediction of the Growth of <i>Salmonella</i> Enteritidis in Raw Ground Beef at Various Combinations of the Initial Concentration of the Pathogen and Temperature

Abstract

Recently we clarified the growth kinetics of Salmonella Enteritidis in raw ground beef at various temperatures with our growth model. Based on those results, this study aimed to build a new methodology to predict the growth of Salmonella in ground beef at given initial concentrations of the pathogen and temperatures. Namely, the maximum cell population of Salmonella at various combinations of its initial concentration and temperature was developed with a polynomial equation. The rate constants of Salmonella growth at various temperatures were estimated with the square root model studied in our recent study. A new system consisting of our growth model, the polynomial equation, and the square root model successfully predicted the growth of Salmonella inoculated at given concentrations in beef at constant and dynamic temperatures. The growth of natural microflora in beef at those temperature patterns were also successfully predicted with the growth model.

Prediction of Competitive Microbial Growth

“…Furthermore, this system precisely predicted the growth at dynamic temperatures as well Fig.11 . The growth of NM in ground beef was also successfully predicted with the NM model and the square root model Figs.10 and 11 Fujikawa et al, 2015 . …”

“…This system shown in Eq. 13 Fujikawa et al, 2015 . log N max 1.3 10 -6 T 3 4.2 10 -4 I 3 3.9 10 -7 T 2 I 1.8 10 -5 TI 2 2.7 10 -3 T 2 9.2 10 -4 TI 8.3 10 -4 I 2 6.5 10 -4 T 5.7 10 -1 I 4.7 13…”

“…13 Fujikawa et al, 2015 . As shown in the figure, the estimated value for log N max was generally higher at higher values for T and I.…”

“…The results obtained for a microbe of concern in raw food material so far lead to the following assumptions: i the value for N max of the microbe in raw food material might be determined with I and T, using a polynomial equation with I and T and ii the value for r at a given value of I might be determined only with T, using a model like the square root model Sabike et al, 2015 . Thus, the growth of Salmonella in the above raw ground beef at various initial concentrations of 2, 3, and 4 log CFU/g at 16, 20, 24, and 28 was studied Fujikawa et al, 2015 . From a total of 12 4 x 3 growth curves, the values of log N max were obtained from the stationary phases of the corresponding growth curves.…”

Prevalence of Salmonella species and Escherichia Coli O157:H7 in organically managed cattle and food safety status of selected meat products

“…This coupled with the low infectious dose of approximately 50 cells (Lim et al, 2010) make the presence of even a small number of cells a risk especially if the product is subject to temperature abuse. Salmonella spp., can also grow at temperatures around 10°C in ground beef (Fujikawa et al, 2015;Juneja et al, 2009). The specific growth rate for Salmonella at 10°C is less than 0.2 log CFU/g/hr (Juneja et al, 2009).The infectious dose of Salmonella spp., varies with strain but temperature abuse can lead to an increase in numbers enough to cause sickness as above 20°C the growth rate is more than 0.4 log CFU/g/hr with a peak of 1log CFU/g/hr at 40°C (Juneja et al, 2009).…”