Abstract
A ready-to-use and self-diffusible dry medium sheet culture system for coliform bacteria, the Compact Dry CF (CDCF) for food, was evaluated . The CDCF was shown to enumerate 26 different strains of coliform bacteria, and to discriminate coliform bacteria from noncoliform bacteria. Of the 26 coliform bacteria that grew on the CDCF, the 26 strains (100%) were blue-green colonies, whereas 8 Gram-negative bacteria other than coliform bacteria formed non-color colonies. Gram-positive bacteria and yeasts did not grow on the CDCF.
The CDCF for coliform bacteria from 80 food samples was compared with the pourplate method using violet red bile agar (VRBA), desoxycholate agar (Deso), X-GAL agar (X-GAL), and the 3M PetrifilmTM CC (PCC) plate method. The correlation coefficients between the CDCF and VRBA, the CDCF and Deso, the CDCF and X-GAL, and the CDCF and the PCC were 0.97, 0.97, 0.97 and 0.99, respectively.
The CDCF is useful for the enumeration of coliform bacteria in food and may be a possible suitable alternative to the conventional pour-plate or PetrifilmTM plate methods
