Splitistoesser D F, Stewart J D, Wilkison M
Institute of Food Science, Cornell University, New York State Agricultural Experiment Station, Geneva, New York 14456.
J Food Prot. 1982 Sep;45(11):1041-1043. doi: 10.4315/0362-028X-45.11.1041.
The resistance to freezing of fecal coliforms isolated from frozen vegetables was compared to that of Escherichia coli isolated from fecal sources. The objective was to see if lower resistance to freezing might explain frozen vegetable samples that contain fecal coliforms but not E. coli . Survivals after 200 d at -10°C in vegetable homogenates ranged from 0.014 to 75% for resuscitated vegetable isolates compared to 0.49 to 18% for resuscitated E. coli isolated from fecal sources. Resuscitation 1 h on Trypticase Soy Agar followed by an overlay with Violet Red Bile Agar (VRBA) increased recoveries about 11-fold over that obtained when the cultures were plated directly on VRBA. Mixed vegetable homogenates permitted higher survivals than homogenates prepared from snap beans, broccoli or mustard greens.
