Qualitative and Quantitative Validation of the Micro Biological Survey Method for Listeria spp., Salmonella spp., Enterobacteriaceae and Staphylococcus aureus in Food Samples

The objective of the present study was the preliminary validation of the qualitative MBS method for Salmonella spp. and Listeria spp. and the quantitative MBS method for Enterobacteriaceae and Staphylococcus aureus. The MBS method is a rapid alternative method for the detection and selective counting of bacteria in agro-food, in water and in environmental samples. It is based on a colorimetric survey in mono-use disposable reaction vials that can be filled with the samples without any preliminary treatment (e.g., homogenization, dilution, etc.); the greater the number of bacteria present in the sample, the faster the color changes. For the qualitative validation of the MBS method for Salmonella spp. and Listeria spp., selectivity, relative accuracy, relative specificity and relative sensitivity were determined. Selectivity, linearity and accuracy were analyzed for the quantitative validation of the MBS method for Enterobacteriaceae and Staphylococcus aureus. The validation here reported has shown that the MBS method for Listeria spp., Salmonella spp., Enterobacteriaceae and S. aureus give similar results and are in agreement with the reference method.