Mathematical Modeling for the Growth of Salmonella spp. and Staphylococcus aureus in Cake at Fluctuating Temperatures

Heeyoung Lee,Hyun Jung Kim,Yu Kyoung Park,Jin Hwa Park

doi:10.3390/app11062475

Heeyoung Lee, Hyun Jung Kim + Show 2 more

Open Access

https://doi.org/10.3390/app11062475

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Abstract

This study aimed to develop dynamic mathematical models to predict the growth of Salmonella spp. and Staphylococcus aureus in a cake under fluctuating temperatures. Among the nine different types of cakes frequently served during school meals, one type of cake was selected based on bacterial growth and water activity. Cocktails of Salmonella spp. and S. aureus were inoculated in the samples and stored at 4–35 °C for up to 336 h. The growth of Salmonella spp. and S. aureus was observed above 20 and 15 °C, respectively. The bacterial cell counts were fitted in the Baranyi model, and the maximum specific growth rate (μmax; log CFU/g/h) and lag phase duration (LPD; h) were analyzed using a polynomial model as a function of temperature (R2 = 0.968–0.988), and the performance of the developed models was appropriate. Furthermore, dynamic models were developed, and the predictions were acceptable in changing the temperature, indicating that the developed dynamic models can successfully predict the outcomes of Salmonella spp. and S. aureus in cake. These results provide useful information for assessing and managing microbial risk in foods by predicting the behavior of Salmonella spp. and S. aureus in cake, especially in changing temperature.

Highlights

Refrigerated baked desserts, such as cake, are considered ready-to-eat (RTE) as they do not need any additional preparation prior to consumption
Salmonella enterica subspecies enterica serotype Enteritidis was identified as the causative agent, and the vehicle of transmission was revealed to be cream cakes made in a bakery and sold at its retail outlets [4]
Centers for Disease Control and Prevention (CDC) reported that these infections from five states resulted from the same strain of Salmonella Agbeni as the Salmonella strain identified in the cake mix [2,5]

Summary

Introduction

Refrigerated baked desserts, such as cake, are considered ready-to-eat (RTE) as they do not need any additional preparation prior to consumption These desserts are popular for their convenience; some of them are associated with outbreaks of foodborne illnesses in the USA, Canada, and other countries worldwide [1,2,3]. A previous study reported that egg white, a chocolate cake ingredient, was contaminated with Salmonella Thomson and was the cause of the outbreak [3] Another outbreak of foodborne infection resulted from the consumption of contaminated cream cake, supporting the need for developing risk management options for cakes and other bakery products. The bacteria outbreaks have been decreased from 372 (2010) to 52, ranked the sixth in Korea [9]

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