Growth of Listeria monocytogenes at 10°C in Biofilms with Microorganisms Isolated from Meat and Dairy Processing Environments.

Listeria monocytogenes was able to grow in multispecies biofilms formed on stainless steel at 10°C in the presence of bacteria isolated from dairy and meat plant environments. Biofilm L. monocytogenes increased more slowly in the presence of competing microflora than in monoculture, but none of the eight competing isolates studied were able to completely exclude L. monocytogenes from the biofilm within 25 days of incubation. Once a population of L. monocytogenes was established on the surface, it invariably increased in numbers. In biofilms containing a mixture of 4 competitive cultures, L. monocytogenes maintained itself at about 1% of the total population.