Validation of Most Probable Number Technique for Determination of Salmonella Typhimurium in Compost, According to EPA 1682/06.

To validate the Most Probable Number technique (MPN) according to the method EPA1682/06 from the U.S. Environmental Protection Agency, in compost and chicken manure, these matrices were inoculated with Salmonella Typhimurium ATCC#14028, defining a double blinded study. In order to include all parameters established for a validation process, 504 samples were used: 252 compost samples and 252 chicken manure samples. The detection limit was 0.8 cells/g for compost and 2 cells/g for chicken manure. In addition, the critical level was 5 UFC/g and the correlation between the results obtained from MPN and Absence/Presence techniques, was a high one, showing an r2 of 0.972.