title: Modeling the Effect of Water Activity, pH, and Temperature on the Probability of Enterotoxin A Production by Staphylococcus aureus.
abstract: The objectives of this study were to develop a probability model of Staphylococcus aureus enterotoxin A (SEA) production as affected by water activity (a(w)), pH, and temperature in broth and assess its applicability for milk. The probability of SEA production was assessed in tryptic soy broth using 24 combinations of a(w) (0.86 to 0.99), pH (5.0 to 7.0), and storage temperature (10 to 30°C). The observed probabilities were fitted with a logistic regression to develop a probability model. The model had a concordant value of 97.5% and concordant index of 0.98, indicating that the model satisfactorily describes the probability of SEA production. The model showed that a(w), pH, and temperature were significant factors affecting the probability of toxin production. The model predictions were in good agreement with the observed values obtained from milk. The model may help manufacturers in selecting product pH and a(w) and storage temperatures to prevent SEA production.
authors.affiliation: Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China; Synergetic Innovation Center of Food Safety and Nutrition, Northeast Agricultural University, Harbin 150030, People's Republic of China. tding@zju.edu.cn.
authors.forename: Tian
authors.initials: T
authors.lastname: Ding
authors.affiliation: Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China.
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Yu
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Residue Chemistry and Predictive Microbiology Research Unit, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
authors.forename: Cheng-An
authors.initials: CA
authors.lastname: Hwang
authors.affiliation: Institute of Food Science and Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, People's Republic of China.
authors.forename: Qing-Li
authors.initials: QL
authors.lastname: Dong
authors.affiliation: Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China.
authors.forename: Shi-Guo
authors.initials: SG
authors.lastname: Chen
authors.affiliation: Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China.
authors.forename: Xing-Qian
authors.initials: XQ
authors.lastname: Ye
authors.affiliation: Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Synergetic Innovation Center of Food Safety and Nutrition, Northeast Agricultural University, Harbin 150030, People's Republic of China; Fuli Institute of Food Science, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China. dhliu@zju.edu.cn.
authors.forename: Dong-Hong
authors.initials: DH
authors.lastname: Liu
mesh_terms: D000818:Animals; D002417:Cattle; D004768:Enterotoxins / Q000096:biosynthesis* / Q000737:chemistry; D016015:Logistic Models; D008892:Milk / Q000382:microbiology; D013211:Staphylococcus aureus / Q000737:chemistry / Q000378:metabolism*; D013696:Temperature; D014867:Water / Q000032:analysis / Q000378:metabolism / Q000502:physiology*
chemical_list: D004768:Enterotoxins; D014867:Water