Evaluation of biofilm formation in stainless steel by Escherichia coli pathotypes isolated from different points in dairy plants of state of São Paulo

Abstract

The contamination of milk may occur during the production, processing, transportation, storage and distribution. During these steps, the milk may incorporate bacteria by contact with surfaces contaminated with bacterial biofilm. The aim of this work is to verify the formation of biofilm on stainless steel by strains of E. coli isolated from three dairy plants in the State of São Paulo. Thirty-eight colonies of E. coli, different pathotypes (enteropathogenic, enterotoxigenic and enteroaggregative), isolated from different points of dairy plants (bulk milk tank, floor, molds and package machines) will be tested. Stainless steel coupons will be immersed in milk artificially contaminated with strains for 10 days at 4°C and 7°C. Biofilm formation will be accessed by counting sessile cells and by scanning electron microscopy.