Identification of Salmonella isolated from pork sausage and evaluation of thermal and antimicrobial resistance of isolates

Abstract

Pork products are important reservoir of Salmonella. In Brazil, the consumption of pork sausage is high and the occurrence of Salmonella in product is usual. Salmonella occurrence was studied in twenty samples of fresh pork sausage. Pulsed-Field Gel Electrophoresis (PFGE) was performed to characterize Salmonella isolates. Their antimicrobial and heat resistance were also evaluated. Salmonella was detected in five samples of industrial pork sausage and six isolates were obtained and identified by phenotypic and genotypic methods: Salmonella enterica subsp. houtenae (two isolates) and serovars of S. enterica subsp. enterica: Bareilly, Typhimurium, Paratyphi C and Paratyphi B. Salmonella houtenae and the serovars Paratyphi B and Typhimurium were resistant to three or more of antimicrobial agents tested. The Salmonella cocktail presented high heat resistance in pork sausage with D-values at 58, 62 and 65°C of 10.99, 5.29 and 2.16 min, respectively, and a z-value of 10.1°C. The evaluation of thermal and antimicrobial resistance of Salmonella can be useful for researchers and food industry involved in the management of pork product quality and resulting in improvements in microbiological safety. According to our results, the binomial effect of time and temperature can be utilized to pork industry in designing and estimating thermal processes specific for sausage. To consumers, a longer heating time ensures the microbiological quality of sausage and reduces the risk of salmonellosis.