Staphylococcus aureus in unripened ewes’ lump cheese. Part 2: Exposure assessment at the time of consumption
2014
Ačai, P. | Valík, Ľ. | Medveďová, A. | Studeničová, A.
An exposure assessment of Staphylococcus aureus in unripened ewes’ lump cheese traditionally produced in Slovakia, and consumed cooled usually up to three day from manufacture, is presented in this study. Predictive microbiological models, together with survey data, were combined with probabilistic modelling to simulate the level of Staph. aureus in unripened lump ewes’ cheese at the time of consumption (model output). The main factors involved in the risk of being exposed to unacceptable levels of Staph. aureus were the distribution density of Staph. aureus in cheese after first 24 h of fermentation, the initial level of lactic acid bacteria (LAB) culture in raw ewes’ milk, the storage at retail/home temperature and the time (model input). The three cases, use by date (UBD), use by date + 1 day (UBD+1) and the worst one (the case of a contaminated udder when the initial counts of Staph. aureus after milking may increase up to 4 log CFU•ml-1), were considered. The results of exposure assessment for the cases use by date, use by date + 1 day and the worst one indicated that, at the time of consumption, 0.4%, 0.5% and 11.5% of manufactured cheeses exceeded the level of 105 CFU•g-1 of Staph. aureus, respectively. Taking the higher content of 106 CFU•g-1 into account as a criterion for unacceptable products, the ratio reached the maximum of 0.1% for the worst case.
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