title: Efficacy of chromocult coliform agar for coliform and Escherichia coil detection in foods.
abstract: Chromocult coliform agar (CCA) was compared with Petrifilm Escherichia coli count plate (PEC) for identifying coliforms and E. coli in a variety of meat products. Products examined included 45 raw beef samples, 12 sausage emulsion samples, 11 samples of meat-based ready-to-eat appetizers, and 8 pork trimming samples. Coliforms from CCA and PEC were confirmed by gassing in brilliant green lactose broth plus a positive reaction on purple broth agar plus lactose after incubation at 35 degrees C for 48 h. Lauryl sulfate tryptose plus methylumbelliferyl-beta-glucuronide and tryptophan broth were used to confirm E. coli from CCA and PEC with 48-h incubations at 35 and 42.5 degrees C, respectively. API 20E test strips were inoculated for final confirmation. The overall respective confirmation percentages (CFU/g) for the PEC and the CCA methods were 93.1 and 93.7% for coliforms and 99.8 and 98.1% for E. coli, although the CCA method yielded significantly (P < 0.001) higher mean CFU/g values for both coliforms and E. coli. Regression analyses of these data indicated a strong positive linear relationship existed between the two methods over a wide CFU/g range for both coliforms and E. coli. The respective correlation coefficients obtained for coliforms and E. coli of 0.89 and 0.86 indicate that the CCA method provides a reliable optional method for these determinations in meat products.
authors.affiliation: R & F Laboratories, West Chicago, Illinois 60185, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Turner
authors.forename: L
authors.initials: L
authors.lastname: Restaino
authors.forename: E W
authors.initials: EW
authors.lastname: Frampton
mesh_terms: D000362:Agar; D001431:Bacteriological Techniques; D003470:Culture Media; D004755:Enterobacteriaceae / Q000302:isolation & purification*; D004926:Escherichia coli / Q000302:isolation & purification*; D005516:Food Microbiology
chemical_list: D003470:Culture Media; D000362:Agar