ABSTRACT
BACKGROUND: CompactDry™ "Nissui" TCR are ready-to-use dry media sheets using a chromogenic medium for the enumeration of mesophilic aerobic bacteria in foods in as little as 24 h. OBJECTIVE: The CompactDry "Nissui" TCR method was validated to achieve AOAC Performance Tested MethodsSM certification. METHOD: The performance of the CompactDry "Nissui" TCR was compared to that of USDA/FSIS MLG 3.02, FDA BAM Chapter 3, and SMEDP Chapter 6 for 11 matrixes. All 11 matrixes were tested by CompactDry incubation at 35 ± 1°C for 24 ± 2 and 48 ± 3 h. The three dairy matrixes were also evaluated by CompactDry incubation at 32 ± 1°C for 24 ± 2 and 48 ± 3 h and additionally at 72 ± 3 h for nonfat dry milk. RESULTS: After log10 transformation of the data, the standard deviation of repeatability (sr) was similar between CompactDry "Nissui" TCR and the respective reference methods, and method equivalence based on the 90% confidence interval of the difference of means being within (-0.5, 0.5) was demonstrated for all matrixes, incubation temperatures, and incubation times in the method developer and independent laboratory studies. The method was shown to be robust, and data are presented supporting product consistency and 18-month shelf life. CONCLUSIONS: The CompactDry "Nissui" TCR method was validated for the determination of mesophilic aerobic bacteria in a variety of matrixes with incubation at 35 ± 1°C for 24 ± 2 and 48 ± 3 h and for dairy matrixes also at 32 ± 1°C for 24 ± 2, 48 ± 3, and 72 ± 3 h. HIGHLIGHTS: The CompactDry "Nissui" TCR method is equivalent to the USDA/FSIS MLG 3.02, FDA BAM Chapter 3, and SMEDP Chapter 6 reference methods and is suitable for Performance Tested MethodsSM certification for the matrixes tested.
