  Shiga toxin-producing Escherichia coli O157: H7 is a food-borne pathogen and
the major cause of hemorrhagic colitis. Pseudomonas is the genus most frequent
psychrotrophic spoilage microorganisms present in milk. Two-species bacterial
systems with Escherichia coli O157: H7, non-pathogenic Escherichia coli, and
Pseudomonas fluorescens in skimmed milk at 7, 13, 19, or 25 C was studied.
Bacterial interactions were modelled after applying a Bayesian approach. No
direct correlation between Pseudomonas fluorescent's growth rate and its effect
on the maximum population densities of Escherichia coli species was found. The
results show the complexity of the interactions between two species into a food
model. The use of natural microbiota members to control foodborne pathogens
could be useful to improve food safety during the processing and storage of
refrigerated foods.
