A new membrane filtration medium, m-ColiBlue24 (mCB), simultaneously detects Total Coliforms (TC) and Escherichia coli (EC) in a single 24-hour incubation. Samples of ground beef, ground pork, and milk were analyzed by mCB and compared to standard methods. When TC from beef and pork samples were compared, there were no significant difference between mCB and pour plating on Violet Red Bile (VRB) agar. In a most probable number (MPN) analysis, nine counts from mCB were within the 95% confidence interval (CI) and 13 were outside the CI. VRB yielded six counts within and 16 outside the CI. The raw milk samples contained confirmed TC counts as high as 9.00X10 2 on mCB and 2.20X10 3 on VRB. Furthermore, the raw milk had up to 1.73X10 3 confirmed EC population. The BBL Crystal system was used to identify representative isolates from mCB and VRB. Of 59 mCB isolates, 64.4% were classical TC. Of the 51 VRB isolates, 62.7% were identified as classical TC.
Iowa State University
Erdmann, J. J.; Dickson, James S.; and Grant, M. A., "Comparative Recovery of Coliforms from Meat and Milk Using m-Coliblue24 and Standard Methods" (1997). Swine Research Report, 1996. 54.