Purpose: To evaluate the performance of a molecular based method with a single and two enrichment step for the recovery of Salmonellafrom frozen comminuted strawberries.
Methods: A Salmonellaspp. cocktail (Typhimurium, Agona, Poona, Bardo and Saint Paul) was used to inoculate -samples of frozen comminuted strawberry by dipping. Three inoculum levels were used: high (50-100 CFU/sample), low (4-8 CFU/sample) and uninoculated level. Each 25g-sample was placed on a sterile bag and added with 225 mL of 3M™ Buffered Peptone Water-ISO and incubated 24h at 35°C (single enrichment protocol). Aliquots of 0.1 mL were transferred to 10 mL Rappaport Vassiliadis broth (RV-10) and incubated 24h at 41.5°C (two step enrichment protocol). All samples were culture confirmed according the FDA-BAM.
Results: No significant differences were found (P>0.05) when this rapid test were compared with the traditional method. Use of a single or double enrichment provides same recovery rate for Salmonella detection regardless the inoculum level (P>0.05). One uninoculated sample was reported as positive by the rapid method and confirmed by culture.
Significance: Use MDA assay with a single enrichment step for detection of Salmonella on frozen and comminuted strawberries provide fast and accurate results that are equivalent to the traditional method.