Microbiological characterization of artisanal minas cheese marketed in São Paulo: safety, hygiene and microbial diversity

Author(s)

Josisleine Recalde Allaion Ferreira

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ)
• Defense date: 2020-11-10

Examining board members

Bernadette Dora Gombossy de Melo Franco; Mariza Landgraf; Luís Augusto Nero

• Advisor: Bernadette Dora Gombossy de Melo Franco

Abstract

There is a wide variety of cheeses in Brazil that fit the concept of \"artisanal minas cheese\". Producers consider that the legislation that regulates the sector, at municipal, state and federal levels, is confusing and excessively strict, hinders the standardization of products, interferes with the growth of the sector and facilitates the marketing of cheeses in disagreement with the hygiene and safety standards. This master\'s research work aimed to generate data on the hygienic-sanitary conditions and microbiological safety of artisanal Minas cheeses, produced in Minas Gerais and collected in São Paulo\'s commerce, as well as to contribute with information about the bacterial diversity in the studied cheeses. One hundred samples of artisanal Minas cheese collected in the São Paulo market were subjected to the enumeration of hygiene indicator microorganisms (coliforms, Escherichia coli and staphylococci), Salmonella and Listeria monocytogenes, using conventional cultivation and also molecular techniques. Coagulase positive staphylococci were studied for tolerance to biocides of interest to food, and microbial diversity was also determined using Next Generation Sequencing in Illumina MiSeq. The results indicated a low occurrence of the studied pathogens, and that 10% and 32% of the samples exceeded the limits for Escherichia coli and coagulase positive staphylococci established by the current legislation, respectively. Among the coagulase positive staphylococci, 37.7% were tolerant to at least one of the tested biocides, with a greater prevalence of those tolerant to benzalkonium chloride (75%). As for microbial diversity, the predominant genera were Streptococcus (32.7%), Lactococcus (30.6%) and Corynebacterium (15.6%). The bacterial microbiota detected in the studied Canastra cheeses showed no dissimilarity when compared to the bacterial microbiota of other Canastra cheeses collected at the production sites in another study. It was observed that the cheese collection regions in the city of São Paulo and the marketing points in São Paulo had a greater influence on the detected bacterial microbiota than the production regions (p<0.05), suggesting the interference of the practices of manipulation after production in the bacterial diversity detected in the cheeses. (AU)

• FAPESP's process: 18/02630-5 - Microbiological characterization of ripened Minas artisanal cheese marketed in São Paulo: safety, hygiene and microbial diversity
• Grantee: Josisleine Recalde Allaion Ferreira
• Support Opportunities: Scholarships in Brazil - Master