A metagenomic approach to the study of microbial ecology and safety of Brazilian artisanal cheeses

Author(s)

Bruna Akie Kamimura Nascimento

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia de Alimentos
• Defense date: 2018-10-31

Examining board members

Anderson de Souza Sant'Ana; Danilo Ercolini; Adriane Elisabete Antunes de Moraes; Carlos Augusto Fernandes de Oliveira; Marciane Magnani

• Advisor: Anderson de Souza Sant'Ana

Abstract

The Normative Instruction n° 30 of August 7th, 2013 from Ministry of Agriculture, Livestock and Food Supply (MAPA) is the legislation for artisanal cheese production in Brazil. The production of artisanal cheese constitutes a seldom documented activity in Brazil. Despite this, the practice of producing cheeses has been spread throughout the years in farms and small rural properties in Brazilian territory leading to the development of a variety of products that are highly appreciated by consumers. Despite its importance in Brazilian food and culture, there are no studies to elucidate the microbial ecology of Brazilian artisanal cheeses through advanced tools such as metagenomics. The knowledge of the microbiota and its interactions in Brazilian artisanal cheeses needs to be elucidated in order to strengthen the quality and safety standards characteristic of these products. Thus, the main objective of this work was to characterize the microbial diversity of different types of artisanal cheeses produced in Brazil, involving 578 samples. The microbiota of 11 types of cheeses from five geographic regions was investigated by sequencing the 16S rRNA gene. In addition, samples from the processing environment of artisanal cheeses (raw materials, final product and surface sponges) were collected from three farms in Serra da Canastra region, Brazil, totalizing 24 samples for investigation of the microbial ecology and analyzed by culture independent method, through the amplicon sequencing. The results showed that lactic acid bacteria were dominant in all types of cheeses, although Enterobacteriaceae and Staphylococcus occurred in cheeses from North, Northeast and Central of Brazil. The genera Streptococcus, Leuconostoc, Lactococcus and Lactobacillus were found, combined differently in terms of relative abundance according to the type of product and the producing region. In natural starter culture and ripened cheese samples there were the dominance of lactic acid bacteria (Lactobacillus, Streptococcus, Lactococcus and Leuconostoc), important to confer the desired characteristics on the final product. On the other hand, possible contaminants as Pseudomonas, Staphylococcus, Pasteurella, Enterobacter, Klebsiella and Acinetobacter, were found in raw milk, floor and cheesecloth samples. These results are important because they provide a microbiological mapping of Brazilian cheeses, highlighting the impact of geographical origin and the mode of production on microbial diversity. In addition, the characterization of these cheeses contributes to the establishment of actions that ensure the quality and microbiological safety of these products (AU)

• FAPESP's process: 13/20456-9 - A Metagenomic and Predictive Modeling Approach to the Study the Microbial Ecology and Safety of Brazilian Artisanal Cheeses
• Grantee: Bruna Akie Kamimura Nascimento
• Support Opportunities: Scholarships in Brazil - Doctorate