Evaluation of petrifilm series 2000 as a possible rapid method to count coliforms in foods.
This research note is a preliminary comparison between the Petrifilm 2000 method and a widely used traditional enumeration method (on violet red bile agar); six batches of different foods (egg, frozen green beans, fresh sausage, a bakery product, raw minced meat, and raw milk) were studied. The reliability of the presumptive counts taken at 10, 12, and 14 h of incubation using this method was also verified by comparing the counts with the total confirmed counts at 24 h. In all the batches studied, results obtained with Petrifilm 2000 presented a close correlation to those obtained using violet red bile agar (r = 0.860) and greater sensitivity (93.33% of the samples displayed higher counts on Petrifilm 2000), showing that this method is a reliable and efficient alternative. The count taken at 10-h incubation is of clear interest as an early indicator of results in microbiological food control, since it accounted for 90% of the final count in all the batches analyzed. Counts taken at 12 and 14 h bore a greater similarity to those taken at 24 h. The Petrifilm 2000 method provides results in less than 12 h of incubation, making it a possible rapid method that adapts perfectly to hazard analysis critical control point system by enabling the microbiological quality control of the processing.
Priego
R
R
Department of Food Science and Technology, University of Córdoba, Spain.
Medina
L M
LM
Jordano
R
R
D000362:Agar / Q000737:chemistry; D000818:Animals; D015169:Colony Count, Microbial / Q000379:methods; D004755:Enterobacteriaceae / Q000254:growth & development*; D005516:Food Microbiology; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D013997:Time Factors
D000362:Agar