Growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions

Joelson Sousa Lima,Mylla Christy Da Silva Dufossé,Ana Paula Presley Oliveira Sampaio,Paula Fernanda Morais De Sousa,Carina Martins De Moraes,Talita Bandeira Roos,Josyane Brasil Da Silva

doi:10.1590/0103-8478cr20200967

Joelson Sousa Lima, Mylla Christy Da Silva Dufossé + Show 5 more

Open Access

https://doi.org/10.1590/0103-8478cr20200967

Copy DOI

Abstract

ABSTRACT: Buffalo milk is rich in nutrients and can serve as a substrate for the proliferation of microorganisms. Thus, the objective of the present study was to evaluate the growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions. Samples of raw and pasteurized milk were inoculated with 1 CFU of each bacterium, separately and together, per 25 mL. After contamination, samples were stored at 8 °C or 37 °C, and bacterial counts were performed at 24, 48, and 168 h. In addition, the accompanying microbiota growth, pH, and the effect of these variables on the growth kinetics of microorganisms were monitored. The pathogens tested were able to proliferate under most conditions tested, reaching high titers throughout the experimental period. At 37 °C, there was a decrease in pH and an increase in the accompanying microbiota that interfered with the microbial growth curve. It was also observed that pasteurized milk subjected to 8 °C provided better conditions for the multiplication of bacteria. Therefore, it was concluded that care throughout the production chain, storage, and commercialization of milk must be adopted to guarantee the microbiological safety of this food.

Highlights

Buffalo milk has important nutritional properties, such as high protein levels and reduced cholesterol content, and has been shown to be beneficial for human consumption
For L. monocytogenes, the strain ATCC 7644 was grown in brain-heart infusion (BHI) broth for 24-48 h, at 37 °C to obtain isolated colonies, and the bacteria were sown on PALCAM agar and cultivated under the same conditions mentioned above
From contamination with 1 colony forming unit (CFU) for each 25 mL of milk, an expressive microbial proliferation was obtained under most conditions tested, especially when the samples were kept at refrigerated temperatures

Summary

Introduction

Buffalo milk has important nutritional properties, such as high protein levels and reduced cholesterol content, and has been shown to be beneficial for human consumption For this reason, it has attracted the attention of consumers (PIGNATA et al, 2014), as well as commercial interest in using this raw material for the elaboration of several derivatives (BITTENCOURT et al., 2013). V.51, n.11, L. monocytogenes and Salmonella enterica serotypes are pathogens commonly reported in outbreaks of foodborne diseases and are prevalent in various types of foods (BRASIL, 2019a; ARSLAN & OZDEMIR, 2020). Both microorganisms represent a serious problem for public health because of the effects caused by infection. It is necessary to monitor the sources of contamination and the dissemination of these agents to ensure food quality and safety

Objectives

Methods

Results

Conclusion