Listeria monocytogenes inhibition by lactic acid bacteria and coliforms in Brazilian fresh white cheese.

Autor: Aragon-Alegro LC; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil., Lima EMF; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil., Palcich G; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil., Nunes TP; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil., de Souza KLO; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil., Martins CG; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil., Noda PK; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil., Destro MT; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil. teresa.destro@altergestao.com.br., Pinto UM; Food Research Center - Department of Food and Experimental Nutrition, Faculty of Pharmaceutical Sciences, University of Sao Paulo, São Paulo, SP, 05508-000, Brazil.
Jazyk: angličtina
Zdroj: Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology] [Braz J Microbiol] 2021 Jun; Vol. 52 (2), pp. 847-858. Date of Electronic Publication: 2021 Jan 19.
DOI: 10.1007/s42770-021-00431-4
Abstrakt: Introduction: Minas fresh cheese (MFC), a Brazilian white cheese, is one of the most popular cheeses nationwide. Studies have shown that Listeria monocytogenes occurrence in this product is generally low, while high populations of coliforms can be found. This study aimed to evaluate the influence of coliforms in the behavior of L. monocytogenes in MFC.
Methods: Pasteurized milk was inoculated with L. monocytogenes and coliforms, and the acidification was made by lactic acid or by the addition of a starter culture. The cheeses of each production were divided into 3 groups and stored at 5 ºC, 12 ºC and cycles of 5 ºC followed by 25 ºC. In predetermined days, samples were taken and L. monocytogenes, coliforms and lactic acid bacteria populations were evaluated, besides the pH, water activity (aw), titratable acidity and NaCl concentration.
Results: The inhibition of L. monocytogenes in the presence of coliforms was observed (p < 0.05), except for those samples prepared with lactic acid and stored at temperature cycles. The values of pH and aw were not sufficiently low to cause inhibition; however, titratable acidity was higher in cheeses containing coliforms. In vitro tests containing lactic acid and L. monocytogenes showed that the bacterium is sensitive to concentration of lactic acid ≥ 0.3%, indicating that lactic acid produced by coliforms strongly influences the population of L. monocytogenes.
Conclusions: Thus, it can be concluded that coliforms negatively impact populations of L. monocytogenes in MFC. We strongly recommend that producers of MFC adopt good hygiene practices to not only avoid contamination with L. monocytogenes, but also coliforms.
Databáze: MEDLINE
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