Purpose: An independent study was conducted to validate this new method in comparison to the ISO/TS 22964 reference method, as part of the NF Validation approval process and according to the ISO 16140 standard.
Methods: The protocol includes an overnight enrichment in BPW. The characteristic colonies are confirmed by running oxidase tests and biochemical galleries. Flexibility is offered by storing the enrichment broth at 5 ± 3 °C for 3 days, before streaking onto the selective agar.
Results: Seventy-seven infant formula samples were analyzed in the relative accuracy, sensitivity and specificity study, which concludes to equivalent performances between the new method and the ISO/TS 22964 methods. The relative detection limits of the new method and the ISO/TS 22964 methods are clearly similar and vary from 0.8 et 1.2 CFU/25 g. The selectivity and specificity of the alternative method was assessed by testing 52 target strains and 31 non-target strains.
Significance: The new method is a reliable alternative method for Cronobacter spp detection in infant formula, and offers important economic savings by reducing time to result and handling time.