A simple procedure to monitor fecal coliforms in seafood processing plants

Various seafoods were inoculated with six different strains of Escherichia coli at two concentrations (about 10 and 100 cells/g). The samples were then either homogenized or massaged in buffer using sterile sample bags. E. coli concentration was estimated using the standard procedure (MPN) or microbiological test kits, Petrifilm-VRB and Redigel-VRB, incubated at 45.5°C. The correlation (r) between counts generated using the standard procedure and those from massaged samples, using any of the media employed, was slightly higher than 0.60. Despite the low correlations among procedures, massaging and inoculating microbiological test kits will detect accidental fecal contamination (>600 cells/100 g), but can be modified to detect contamination ≤230 cells/100 g. Probabilities involved in estimated fecal coliform concentration, when few colonies are observed, are discussed.