Evaluation of a rapid fluorogenic method for the detection of Escherichia coli in dairy products.
A rapid fluorogenic medium was evaluated for the detection of Escherichia coli in dairy products. The medium was capable of detecting Esch. coli after 7.5 h incubation at 41.5 degrees C. Samples of pasteurized milk (136), raw milk (63), soft cheese (60) and pasteurized cream (39) were examined with media based on 4-methylumbelliferyl-beta-D-glucuronide (MUG-7) and Violet red bile agar and there were no significant differences between the numbers of Esch. coli detected on the two media. MUG-7 medium had a specificity of 98.6% and the small number of organisms giving a false positive reaction were identified as Klebsiella pneumoniae. The incidence of false negative results was approximately 2%. MUG-7 medium was suitable for pour plate, spread plate and membrane filtration methods. Possible applications of the method are discussed.
Sarhan
H R
HR
Department of Biological Sciences, University of Salford, UK.
Williams
L R
LR
Foster
H A
HA
D000818:Animals; D002611:Cheese; D003470:Culture Media; D003611:Dairy Products; D004926:Escherichia coli / Q000302:isolation & purification*; D005188:False Negative Reactions; D005189:False Positive Reactions; D005456:Fluorescent Dyes; D005516:Food Microbiology; D006923:Hymecromone / Q000031:analogs & derivatives; D008892:Milk / Q000382:microbiology*; D011237:Predictive Value of Tests
D003470:Culture Media; D005456:Fluorescent Dyes; D006923:Hymecromone; C034888:4-methylumbelliferyl glucuronide