Comparison of a Rapid Plate Count and MPN Methods for Enumeration of Fecal Coliforms and Escherichia coli in Soft-Shell Clams.

A direct elevated temperature plate count method utilizing modified fecal coliform agar with rosolic acid (ETPC/mFC) was compared to 5-tube and 3-tube most probable number (MPN) procedures for its accuracy in enumerating fecal coliforms and Escherichia coli in naturally and artificially contaminated soft-shell clams ( Mya arenaria ). The results indicated that the extent of overall recovery of fecal coliforms was similar in the two methods tested. Therefore, the ETPC/mFC method may be considered as a rapid procedure for fecal coliform screening during depuration of soft-shell clams.

Fate of Listeria monocytogenes in Shredded Cabbage Stored at 5 and 25°C under a Modified Atmosphere.

Shredded cabbage was inoculated with Listeria monocytogenes Scott A cells and stored in normal air or a modified (70% carbon dioxide and 30% nitrogen) atmosphere at 5 and 25°C. Under the normal atmosphere at 25°C, colony counts increased by 2 logs within 2 d of storage but then decreased to undetectable levels within 6 d of storage. In the modified atmosphere at 25°C, numbers also decreased to undetectable levels within 6 d, but with a less marked initial increase and a decline that was more rapid than in the unmodified atmosphere.