Factors influencing production of Salmonella enterotoxin (Stn)

Abstract

Salmonella enterotoxin (Stn) is an important food borne agent affecting public health. The study evaluated the influence of different physico-chemical factors on in-vitro production of Stn. The Stn production was tested by Staphylococcal Co-agglutination test. The highest secretion of Stn was found in cell free culture supernatant (CFCS) of tryptic soya broth culture followed by brain heart infusion broth and biken broth, while the least production was observed in nutrient broth. Growth with constant shaking (200 rpm) had positive influence on Stn production. Maximum Stn production was also recorded during an incubation temperature of 32 0C to 37 0C than 22 0C and 270C while minimum was at 42 0C. Peak production was at 18 to 24 hours incubation which sustained beyond 48 hours. The pH (6-8) influenced Stn production and decreased at pH beyond 9. Bacterial cells sonicates yielded more Stn than CFCS. Results showed that the physico-chemical factors influence the Stn production.