Influence of holding temperature on the growth and survival of Salmonella spp. and Staphylococcus aureus and the production of staphylococcal enterotoxin in egg products

In this study, growth and survival of Salmonella spp. and Staphylococcus au reus in steamed egg and scrambled egg held at 5, 18, 22, 37, 55 and 60 degr eesC are investigated. The production of staphylococcal enterotoxin in stea med egg is also examined. Results reveal that Salmonella spp. and Staph. au reus in the egg products multiply best at 37 degreesC, followed closely by 22 and 18 degreesC. Neither pathogen showed growth in the egg products held at 5 degreesC. Initial inoculation dose, holding temperature and holding t ime affected the population of both organisms found in the egg products. St aphylococcal enterotoxin A (SEA) and B (SEB) are detected only in the egg p roducts held at 37 or 22 degreesC. After holding at 37 degreesC for 36 h, s crambled egg inoculated with ca. 5.0 log cfu/g Staph. aureus contains the h ighest levels of SEA (> 64 ng/g) and SEB (> 64 ng/g). Although Salmonella s pp. and Staph. aureus grow better in steamed eggs than in scrambled eggs, p roduction of staphylococcal enterotoxin, in general, was higher in scramble d eggs than in steamed eggs. On the other hand, a repaid destruction of the test organisms in steamed eggs held at 60 degreesC was observed. Holding t he steamed eggs at 60 degreesC, Salmonella spp. and Staph. aureus with an i nitial population of ca. 5.9 and 5.6 log cfu/g, respectively, reduced to a non-detectable level in 1 h. (C) 2001 Elsevier Science B.V. All rights rese rved.