Micro ecosystems from feed industry surfaces: a survival and biofilm study of Salmonella versus host resident flora strains

Surface microflora characterization from two feed productions plants, by means of 16 S rDNA sequencing, revealed a wide diversity of bacteria. Survival, disinfection and biofilm formation experiments were conducted on selected dominant resident flora strains and Salmonella. Results showed higher survival properties by resident flora isolates for desiccation, and disinfection compared to Salmonella isolates. Dual-species biofilms favored Salmonella growth compared to Salmonella in mono-species biofilms, with biovolume increases of 2.8-fold and 3.2-fold in the presence of Staphylococcus and Pseudomonas, respectively.These results offer an overview of the microflora composition found in feed industry processing environments, their survival under relevant stresses and their potential effect on biofilm formation in the presence of Salmonella. Eliminating the establishment of resident flora isolates in feed industry surfaces is therefore of interest for impeding conditions for Salmonella colonization and growth on feed industry surfaces. In-depth investigations are still needed to determine whether resident flora has a definite role in the persistence of Salmonella in feed processing environments.Salmonella contaminations in animal feeds are important vectors for Salmonella infections in livestock farms [1-9]. The presence of Salmonella enterica serovars in feed ingredients is a well-known problem. Heat treatment of animal feed is central for ensuring microbial feed safety, despite the fact that some reports stated that thermal treatment conditions during pelleting are not effective for eliminating Salmonella contamination in feeds [10,11]. However, since most feed plants have good control over heat treatment procedures, feed contamination is most likely due to recontamination from feed processing environments [12]. Despite strict safety measures implemented by the feed industry in Norway, certain Salmonella serovars (e.g. Agona, Montevideo and Senftenberg) are routinely