Resumo

Background: In the food industry, the adhesion of microorganisms to the surface of equipments used in the food processing results in serious problems, since biofilm is potentially a chronic source of contamination that may compromise the quality of milk. Enterotoxigenic staphylococci are leading food poisoning agents worldwide due to a wide range of toxin-mediated virulence factors. We aimed to evaluate the production of biofilm by Staphylococcus spp isolated from caprine milk and equipments of small-scale goat dairy plants in Paraiba State, Northeastern Brazil. Methods: A total of 47 staphylococci isolates (20 from raw goat milk, 13 from pasteurized goat milk and 14 from swabs taken from equipment’s surface) were screened phenotypically for biofim formation using the Congo red agar method. Congo red agar dishes were incubated at 35°C for 24 hours for up to 72 hours of incubation. Staphylococcus aureus ATCC 25923 and S. epidermidis ATCC 12228 were used as positive and negative controls, respectively. Results and Discussion: Eleven staphylococci isolates (23.4%) were considered biofilm-producing Staphylococcus, from which eight (17%) were cultured from raw milk; 1 (2.1%) from pasteurized milk and 2 (4.2%) from equipment’s surface. Amongst the investigated isolates, nine were coagulase positive staphylococci, from which eight (88.9%) were considered biofilm-forming isolates. However, considering the limitations of the Congo reg agar method and its low correlation with other methods for the analysis of biofim formation, microplate Alamar blue assay and PCR for the detection of the genes icaA and icaD have also been performed. Further analyses on the molecular mechanisms associated with the biofim producing traits of the investigated staphylococci might contribute to the understanding of the real role of biofilm-forming staphylococcus in the goat dairy processing plants.