Purpose : The objective of this study was to evaluate the thermal resistance of S. aureus in various RTH sauces.
Methods: A five-strain mixture (S. aureus KACC11596, S. aureus KACC10768, S. aureus KACC10778, S. aureus KACC13236 and S. aureus NCCP10862) was inoculated in 5 g of pork cutlet, meat and Carbonara sauces at 7 log CFU/g. The inoculated samples were then exposed to 60, 65 and 70°C, and survivals of total bacteria and S. aureus were enumerated on tryptic soy agar and mannitol salt agar, respectively every 30 min for 2 h. Moreover, survival data of S. aureus were fitted to the Baranyi model to calculate death rates, and least squares means for survivals were compared using Tukey's method.
Results: Total bacteria and S. aureus cell counts in pork cutlet sauce significantly decreased (P < 0.05) without tailing effect (no reduction of bacterial cell counts) for all heating temperatures. Cell counts of total bacteria and S. aureus in meat sauce and Carbonara sauce declined (P < 0.05) by 2 log CFU/g after 30 min heating at 60 and 65°C, followed by very obvious tailing effect after 30 min. However, cell counts of S. aurues in meat and Carbonara sauces linearly decreased (P < 0.05) for 2-h heating.
Significance: The result indicates that meat sauce and Carbonara sauce should be appropriately heated at high temperature to destroy S. aureus cells.