Use of a Most Probable Number Method Modified with a Deoxyribonucleic Acid Probe to Monitor Control by Food Preservatives of Natural Salmonella Contamination in Animal Meat Meals

A most probable number (MPN) technique using a DNA probe was developed for determination of Salmonella in naturally contaminated meat meals. The method eliminated the need for 180 selective plates and 75 selective tubes and saved 27 h when compared with a traditional technique; yet it still yielded identical MPN of Salmonella per 100 g in five naturally contaminated samples. The method was used to monitor the effect of a commercial food preservative (Sal Curb) at 0, .25, .50, 1.0, and 2.0% in meat meals with initial contaminations of 1,100, 93, or 7 MPN organisms/100 g. The preservative greatly reduced MPN in the 1,100 and 93 MPN samples in a time and dose-dependent manner, but in the sample with 7 MPN organisms/100 g of material, it resulted in 0 MPN organisms per 100 g after 24 h at all levels tested.