The enumeration of sublethally injured populations of Staphylococcus aureus in foods |
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| Authors: | P van Netten J van der Ven F Jaisli † D A A Mossel ‡ |
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| Institution: | Netherlands Government Food Inspection Service, 's-Hertogenbosch, The Netherlands;†Obi Pektin A.G., Bischofszell, Switzerland;‡Professor Christiaan Eijkman Foundation, Netherlands' Government University at Utrecht, The Netherlands |
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| Abstract: | Substantiating earlier investigations, pure cultures of Staphylococcus aureus were found to be equally well recovered on Baird-Parker agar at 37°C as at 42°C, whereas Micrococcus spp. are suppressed at the latter temperature to an extent exceeding 5 log10 cycles. It was also established that egg yolk dissimilation by Staph. aureus is intensified at 42°C. Heat treated (60°C) populations of Staph aureus were quantitatively recovered on Baird-Parker agar at 42°C, though acid-injured populations were not. Acid-injury (2% lactic acid at 37°C) could be completely restored by solid medium repaiar during at least 6 h at 23°C on tryptone soya peptone yeast extract egg yolk pyruvate agar. Pure culture studies were confirmed in surveys on trade samples of foods. |
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