Studies on the optimization of the examination of milk and milk products for salmonellae

To avoid time consuming culturell selective enrichment and confirmation ste ps included in methods for the detection of salmonellae liquid selective me dia were replaced by immunomagnetic separation and immunoconcentration tech niques, and solid selective media by an EIA (VIDAS SLM). Different types of dried milk products were artificially contaminated with sublethally injured salmonellae (1-10 and 10-100/25 g), whereas raw milk an d soft cheese were contaminated in the same way but with uninjured bacteria . In the case of dried milk products, raw milk with a relatively high bacteri al load ("Milch-ab-Hof") and soft cheese combinations of these concentratio n steps with the EIA worked not successfully. Using certified raw milk ("Vo rzugsmilch") with lower bacterial counts even very low numbers of salmonell ae could be detected within 24 h.