Purpose: The purpose of this study was to evaluate the use of DNAble for Salmonella spp. detection in dry pet food and poultry environmental swabs. DNAble is an isothermal DNA amplification system with significantly reduced TTR (15 min amplification time) compared to PCR, and requires minimal sample preparation.
Methods: The DNAble Salmonella spp. detection kit was validated (1) on dry pet food and poultry environmental swabs. Instrument variation was tested across two instruments. For ruggedness studies, a combination of eight different assay parameters were varied, while for product consistency tests, two different lots of test kits were evaluated. At least eight technical replicates were tested per study. A total of 50 Salmonella serovars and 20 non-Salmonella strains were tested for inclusivity and exclusivity, respectively. At least two biological and eight technical replicates were tested for reproducibility trials. Statistical evaluation near the limit of detection per AOAC was used for data analysis (1).
Results: The assay exhibited analytical sensitivity of < 50 genome copies/reaction and a reproducible limit of detection of < 10 CFU/ml post-enrichment. Inclusivity and exclusivity data indicate 100% accuracy. Statistically equivalent performance (95% CI) was observed during the instrument variation and product consistency studies, and in seven of eight combinations of non-standard assay user interface parameters tested during ruggedness studies.
Significance: These data support the capacity of DNAble for Salmonella spp. detection in dry pet food and poultry environmental swabs.
Reference: (1) http://www.aoac.org/imis15_prod/AOAC_Docs/StandardsDevelopment/AOAC_Validation_Guidelines_for_Food_Microbiology-Prepub_version.pdf