[Modified rapid method for the quantitative determination of S. aureus in food products and washings]

Suggested is the use of a modified rapid method for the quantitative determination of Staphylococcus aureus in food products and washings, worked out on the basis of the method described by Lachica [8]. In the modified method a yolk-salt agar is substituted for Baird-Parker's medium. Provided is inactivation of the thermolable nucleases at 65 degrees C for one hour and additional incubation at 37 degrees C for 2 hours following the overlaying of the agar with toluidineblue DN-ase agar. Comparative investigations on the quantitative determination of Staphylococcus aureus in experimentally and naturally contaminated food samples and washings showed that there were no essential differences between the microbial counts as established by the two methods. The modified method made it possible to shorten the investigation by 2 hours. It proved specific and readily applicable for rapid laboratory diagnostics.