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Listeria monocytogenes incidence changes and diversity in some Brazilian dairy industries and retail products

Oxaran, Virginie, Lee, Sarah Hwa In, Chaul, Luíza Toubas, Corassin, Carlos Humberto, Barancelli, Giovana Verginia, Alves, Virgínia Farias, de Oliveira, Carlos Augusto Fernandes, Gram, Lone, De Martinis, Elaine Cristina Pereira
Food microbiology 2017 v.68 pp. 16-23
Listeria monocytogenes, cheeses, clones, commercialization, dairies, dairy industry, foodborne illness, laws and regulations, listeriosis, monitoring, multilocus sequence typing, pathogens, risk, Brazil
Listeria monocytogenes can cause listeriosis, a severe foodborne disease. In Brazil, despite very few reported cases of listeriosis, the pathogen has been repeatedly isolated from dairies. This has led the government to implement specific legislation to reduce the hazard. Here, we determined the incidence of L. monocytogenes in five dairies and retail products in the Southeast and Midwest regions of Brazil over eight months. Of 437 samples, three samples (0.7%) from retail and only one sample (0.2%) from the dairies were positive for L. monocytogenes. Thus, the contamination rate was significantly reduced as compared to previous studies. MultiLocus Sequence Typing (MLST) was used to determine if contamination was caused by new or persistent clones leading to the first MLST profile of L. monocytogenes from the Brazilian dairy industry. The processing environment isolate is of concern being a sequence-type (ST) 2, belonging to the lineage I responsible for the majority of listeriosis outbreaks. Also, ST3 and ST8 found in commercialized cheese have previously been reported in outbreaks. Despite the lower incidence, dairy products still pose a potential health risk and the occurrence of L. monocytogenes in dairies and retail products emphasize the need for continuous surveillance of this pathogen in the Brazilian dairy industry.