Occurrence of non-O157 Shiga toxin-encoding  Escherichia coli  in artisanal  mozzarella cheese in Brazil: risk factor associated with food workers

Patricia   Cardoso; José Moacir   Marin

Occurrence of non-O157 Shiga toxin-encoding Escherichia coli in artisanal mozzarella cheese in Brazil: risk factor associated with food workers

Autores

Patricia Cardoso

José Moacir Marin

Editor

Sociedade Brasileira de Ciência e Tecnologia de Alimentos

Descripción

Mozzarella cheese is considered a safe food due to the high temperature treatment used in the traditional process of stretching into hot water; however, a post-process contamination during the cheese manufacture or during the processing (before distribution) could occur. This study investigated the occurrence of Shiga toxin-encoding Escherichia coli (STEC) strains in homemade-mozzarella cheese. In total, 59 raw milk cheese samples collected at a local producer in the Jequitinhonha Valley (Northeast of Minas Gerais, Brazil) were submitted for microbiological analysis, and 38 (64.4%) tested positive for E. coli . Then, 147 strains of E. coli were isolated from positive samples and screened by polymerase chain reaction for the presence of the genes encoding the following virulence factors: stx 1 and stx 2 (verotoxin types 1 and 2) and eae (intimin). All the isolates were negative for the stx 2, 14 isolates (9.5%) were positive for the stx 1 gene, and 11 of them also harbored the eae gene. A food worker was probably involved in cheese contamination during the manufacture schedule. While the development of STEC infection in humans is not completely understood, all STEC- contaminated food can be considered potentially hazardous. Keywords: Escherichia coli ; virulence genes; homemade cheese; food handler contamination. Practical Application: This study demonstrates that mozzarella cheese may be a vehicle for STEC non-D157 strain dissemination among humans, which is a reason for concern due to the high consumption of this cheese by the Brazilian population.