Sterile samples of skim milk were inoculated with Listeria monocytogenes (strain Scott A, California, or V7), Flavobacterium lutescens or Flavobacterium species, or a combination of L. monocytogenes plus flavobacteria and incubated at 7 or 13°C for 8 weeks. McBride Listeria agar was used to determine populations of L. monocytogenes at 0, 7, 14, 28, 42, or 56 d, and plate count agar was used to enumerate flavobacteria at the same time intervals. Growth of L. monocytogenes was significantly (P<0.05) enhanced during incubation at 7 or 13°C in mixed cultures with F. lutescens. When tested with Flavobacterium sp. ATCC 21429, numbers of L. monocytogenes decreased insignificantly (P<0.05) in mixed cultures compared to pure cultures. L. monocytogenes did not affect growth of flavobacteria; also, no marked changes in pH of the milk were caused either by L. monocytogenes alone or by mixed cultures.

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