Efeito de ácido e baixas temperaturas sobre Salmonella enterica sorovar Enteritidis em carne suína

• Autor(a) principal: Silva, Simone Quintão
• Data de Publicação: 2006
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5352
• topic: Salmonella; Enteritidis; Ácido; Temperatura baixa; Estresse; Salmonella; Enteritidis; Acid; Low temperatures; Stress; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::MICROBIOLOGIA AGRICOLA

Considering that the acid tolerance is an important virulence factor related to survival at low pH of gastric barrier of foodborne pathogens and the expressive increasing of prevalence of Salmonella serovar Enteritidis in recent years as etiologic agent of human salmonelosis, this work aimed to evaluate the effect of acid and storage under low temperatures on Salmonella serovar Enteritidis. The growth of S. Enteritidis CCS3 isolated of swine carcass and S. Enteritidis ATCC 13076 at Trypticasein and Soya Broth (TSB) with pH values between 3.5 and 7.2 and the survival in the same media with pH values between 1.5 and 3.5 were investigated. The tolerance to simulated gastric fluid (SGF) of these cells previously sublethal acid treatment pH 4.0, 4.5 and 5.0 inoculated in pork maintained storage by 7 days at 4 ± 1°C and by 84 days at freezing temperature (-18°C ± 1) was also evaluated. S. Enteritidis CCS3 presented higher values of specific growth rate in acidified TSB and this culture had longer time survival in pH < 3,5 than S. Enteritidis ATCC 13076. The storage in pork by seven days at 4 ± 1°C did not effect the populations of S. Enteritidis studied. After 84 days of cold storage, the media of population reductions of S. Enteritidis CCS3 and ATCC 13076 were 0.8 and 1.5 log cycle, respectively. The previous acid treatment did not enhance the survival of both cultures at low temperatures. After low temperature storage, the cells of S. Enteritidis CCS3 were tolerant until three hours SFG exposure. Instead, cells of S. Enteritidis ATCC 13076 lost culturability after 10 minutes of SFG challenge. S. Enteritidis CCS3 cells submitted to acid treatment at pH 4.0 showed are more tolerant to 180 minutes SFG exposure (15% of population reduction) than cells submitted to other acid treatments (pH 4.5 and 5.0) and cells of control (without acid treatment) with 30% of population reduction.