The method of Hartman et al. for recovering stressed coliform bacteria was evaluated in a group study. The experimental medium, VRB-2, was more productive than VRB medium by 31% for raw milk, 70% for ice cream and 61% for cottage cheese. Differences in colony counts of coliforms caused by incubating for 48 vs. 24 h and by boiling vs. autoclaving were not statistically significant. Among 40 samples tested in two laboratories, counts obtained at 30 vs. 32 C were not significantly different.
1Department of Food Science and Nutrition, University of Missouri-Columbia, Columbia, MO 65201.
2Department of Bacteriology, Iowa State University, Ames, IA.
3Department of Animal and Dairy Sciences, Auburn University, Auburn, AL.
4Health Department, Springfield, MO.
5Department of Nutrition and Food Sciences, Utah State University, Logan, UT.
6Dairy Science Department, South Dakota State University, Brookings, SD.
7Mid-America Farms, Springfield, MO.
8Dean Foods Company, Rockford, IL.
Contribution from the University of Missouri Experiment Station, Journal Series No. 8031.