The “Rapid’Salmonella” Method: Estimation of the Limit of Detection for Salmonella Strains Typhimurium and Enteritidis Isolated from Frozen Poultry Meat

Abstract

As a part of evaluation the surveillance system of Salmonella in frozen imported poultry meat into Jordan, we conducted a study to estimate the limit of detection (LOD50% and LOD95%) of S. Typhimurium and S. Enteritidis based on chromogenic media of Rapid’Salmonella method. Salmonella-free chicken meat samples was inoculated with 1 to 100 CFU of 11 wild strains that originated from frozen imported poultry meat and 2 reference strains. In the experiment, the observed lowest concentration for Salmonella Typhimurium and Salmonella Enteritidis using Rapid’Salmonella method were from 1 to 50 CFU/25 g. Based on these results, probability of detection (POD) curve was estimated according to the model described in EN ISO 16140-4. From the estimated POD functions, the LOD50% and LOD95% was determined for the Rapid’Salmonella method. The LOD50% of the different strains varied from 0.9 to 21.2 CFU/25 g. The two reference strains and 9 wild strains had a LOD50% less than 2 CFU/25 g, one wild strain of Salmonella Enteritidis had a LOD50% of 6.8 CFU/25 g and another one had a LOD50% of 21.2 CFU/25 g. The majority of Salmonella strains has a LOD50% of 1-4 CFU/25 g in poultry meat, but also that there are some Salmonella strains which will first be detected at 10 CFU/25 g and higher.