Detection of Staphylococcus aureus Within Starter Culture Preparations Containing Staphylococcus carnosus

A method is described that permits the detection of contamination by Staphylococcus aureus within starter culture preparations containing Staphylococcus carnosus . Using selective media and raised incubation temperature it was possible to distinguish between starter and contamination organisms. The detection limit was 10³ S. aureus within 10¹¹ S. carnosus by the drop-plate method. With a modified most probable number (MPN) technique the detection limit was even lower. The time needed varied between 24 and 72 h depending on the concentration of the contaminant and the method used. The method described therefore proved to be suitable for routine microbiological quality control regarding the microbiological status of starter preparations containing bulk starter staphylococci. The drop-plate method furthermore proved to be suitable for the detection of S. aureus within starter preparations of pediococci and lactobacilli.