Comparative examination and validation of Salmonella immuno dot-blot strip in poultry samples

A.R. Rafidah and N.A. Masdor

Abstract
Efficient and rapid monitoring of Salmonella in the poultry production chain is necessary to assure safe food products for consumers. Previously, an immuno dot-blot test strip based on polyclonal antibody against Salmonella typhimurium was successfully developed. However, validation is needed to ensure that their performance is equal to established methods. Thus, a comparative study of the diagnostic immuno dot-blot procedure with the standard culture-based method using Salmonella selective chromogenic agar and other commercially available kits were performed. Samples of refrigerated chicken cuts were spiked with S. typhimurium before being tested for specificity, sensitivity, and cross-reactivity of the test strip. The results showed that the immune dot-blot strip was comparable with Salmonella Chromogenic agar and commercial kit. To determine the specificity of the strip, cross-reactivity between four species of the Enterobacteriaceae family and Salmonella as an indicator was carried out. This strip exhibits high selectivity against V. cholera, L. monocytogenes and Shigella, although cross-reaction was observed with E. coli. The results obtained revealed that immuno dot-blot strip gave comparable results with existing Salmonella detection methods in terms of time and accuracy. Thus, these results proved this strip is useful as a rapid diagnostic test for the direct detection of Salmonella in food.

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