Purpose: The objective of this study was to evaluate the new assay for both detection and confirmation of Salmonella.
Methods: Samples were pre-enriched in buffered peptone water (BPW) for 18-24 hours at 37°C and then enriched in the selective SX2 broth overnight at 41.5°C. For the confirmation protocol, a Salmonella presumptive colony was re-suspended into 1 ml of BPW. Samples were boiled for 5 minutes before testing. Positive results visualized as a blue line were obtained in 20 minutes.
Results: The comparative study between the new method and the ISO 6579 reference method was performed on 276 products. Most of the positive samples were artificially inoculated with stressed Salmonella at a very low level. One hundred and fourteen samples were confirmed positive by the reference method and 109 by the new method. No statistically significant difference (X2 < 3.84) was observed between both the methods. In the confirmation protocol, the new assay was compared with an other commercial lateral flow assay and with a commercial latex assay on 59 Salmonella strains representing 18 different serovars. Fifty-seven were confirmed as Salmonella by the bioNexia assay, 50 with the latex assay and only 35 with the other commercial lateral flow assay. The two missed strains were further confirmed after a short enrichment in BPW.
Significance: This study demonstrates that the bioNexia Salmonella method can be a valuable alternative for detection of Salmonella in food samples. Without requiring skilled personnel and well-equipped laboratory, it can be a simple and rapid method for detection of Salmonella. Thanks to the selected antibody cocktail this assay showed significant higher rate of Salmonella identification compared with two commercial assays.