Predictive modeling on the growth of Staphylococcus aureus inoculated on Korean style cooked foods stored at various temperatures

Abstract

This study was conducted to develop predictive models for the growth of Staphylococcus aureus on Korean style cooked foods (potato salad, stir-fried boiled fish paste, seasoned baby aster, and stir-fried anchovies) as a function of various storage temperatures (from 15 to 35°C). The modified Gompertz equation was applied to fit the growth curves. Potato salad, stir-fried boiled fish paste, and seasoned baby aster showed the greatest specific growth rate by 1.219, 0.782, and 1.282 log 10 CFU/h and the shortest lag time by 0.283, 0.407, and 0.374, respectively, when stored at 35°C. No growth of S. aureus was observed in stir-fried anchovies due to its low water activity. Subsequently, these results were employed to establish the secondary models, which were further used for validation using accuracy factor and bias factor. Overall, accuracy factor of less than 1.461 and bias factor of less than 1.093 were observed depending on different storage temperatures and a sort of contaminated food samples. These results will be used to develop the manual representing the safe storage period of Korean foods contaminated with pathogenic bacteria.

Response surface modeling for the inactivation of Bacillus cereus on cooked spinach by natural antimicrobials at various temperatures

“…The antimicrobial substances were chosen on the basis of their potential antimicrobial activity against pathogens. In previous studies, the minimum inhibitory concentration (MIC) for antimicrobial substances as a single or combination treatments against various spoilage bacteria of fresh produce was evaluated (Hong, ; Yoon, ). In all cases, antimicrobial substances were of the highest grade available (98–100% pure).…”

“…In all cases, antimicrobial substances were of the highest grade available (98–100% pure). Stock solutions of thymol, acetic acid, and nisin were prepared in 50% ethanol, sterile distilled water, and 0.02 N hydrochloric acid (Daejung Chemical Co., Gyeonggi‐do, Republic of Korea), respectively (Bari et al, ; Gavliakova et al, ; Yoon, ; Zheng, Bae, Jung, Heu, & Lee, ). Treatment solutions of antimicrobial substances were prepared as follows: thymol (0.01%, wt/vol), acetic acid (0.66%, wt/vol), and nisin (0.02%, wt/vol).…”