Evaluation of BAM with VIDAS Immunoassay Method for Identifying Salmonella on Tomatoes Surface

Introduction: Salmonella has been implicated as a major cause of human foodborne illness worldwide, and several outbreaks of salmonellosis associated with tomatoes have recently been reported. There is an increase demand for effective detection methods which are rapid, accurate and easy to apply.

Purpose: This study evaluated the Mini Vidas Salmonella (SLM) (bioMérieux) method in relation to its ability to detect Salmonella cells artificially inoculated on tomato surfaces.

Methods: Tomatoes without any defects (peel ruptures, bruised areas) were used in the experiment. A total of 168 tomatoes were artificially inoculated on the surface at levels of 10, 10² and 10³ CFU/tomato with Salmonella Brazil and left to dry inside the air cabinet. These contaminated tomatoes were analyzed simultaneously by Mini Vidas (SLM) and BAM methods. Test for significant difference (x²) between the methods was evaluated as described by McNemar´s test.

Results: The proportion of samples confirmed positive by the alternative method is not statistically different from the proportion confirmed positive by the reference method (BAM) in all inoculated levels tested. Overall, the Mini Vidas (SLM), method recovered Salmonella in 106 test samples compared to 87 for the cultural method, resulting in an 82% overall agreement between the two methods.

Significance: The results indicated that the rapid method Mini Vidas Salmonella (SLM) may be effective for the analysis of this microorganism on tomato surface.