Introduction
The methods described in this guidebook are for use by the FSIS laboratories. FSIS does not specifically endorse any of the mentioned test products and acknowledges that equivalent products may be available for laboratory use.
FSIS utilizes the following performance criteria when evaluating the suitability of an alternative laboratory method or product for a given analyte and sample matrix pair:
•Sensitivity of 90% or greater
•Specificity of 90% or greater
•Accuracy of 90% or greater
•Positive predictive value of 90% or greater
•Negative predictive value of 90% or greater
Performance criteria are relative to the reference cultural method for that analyte and sample matrix as outlined in the corresponding MLG chapter. Method validation is necessary to demonstrate the equivalence of alternative tests as detailed in the document titled “FSIS Guidance for Evaluating Test Kit Performance.”
This method describes the analysis of various meat, poultry and Siluriformes (fish) products, sponge and rinse samples, and egg products for Salmonella.
It is not intended for the isolation and identification of Salmonella typhi.
Success in isolating Salmonella from any food can be related to a number of factors including food preparation procedures, the number of organisms present, sample handling after collection, etc. With raw samples, the competitive flora may be the most important factor. It varies from sample to sample and from one kind of matrix to another.
Another consideration is whether the examination is for routine monitoring or epidemiological purposes. The analyst may choose to augment the method for epidemiological purposes with additional enrichment procedures and culture media, two temperatures of incubation, intensified selection of colonies from plates, and/or rapid screening methods.
Unless otherwise stated all measurements cited in this method have a tolerance range of +/-2%.
