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V. R. DEIBEL, Brian Wave Technologies, Inc., 124 Owen Rd., Madison, WI 53716 Biofilms, while prevalent within dairy plants, are difficult to identify, locate and remove. Biofilm presence in dairies may result in pathogen cross-contamination, product defects such as package bloating, decreased shelf life, and off flavors, odors and textures. Biofilm formation starts with the development of a conditioning layer allowing for bacterial adhesion. Once attached, bacteria produce and excrete exopolysaccharides that aid in facilitating stronger attachment to surfaces and serve to protect bacteria from cleaners and sanitizers. Pili, fimbriae, flagella, hydrostatic, hydrogen and covalent bonds, along with Van der Waals interactions mediate bacterial adherence. Stainless steel, plastic and concrete are examples of surfaces that have been found to harbor biofilms. Scratched, welded or damaged surfaces provide bacterial attachment sites and therefore are more conducive for biofilm formation. Areas that are difficult to clean are additional sites known to harbor biofilms. Within 8 hours of initial adherence, 91% of bacteria are irreversibly attached necessitating intensified mechanical activity and strong chemical application for removal. Any bacteria present in the environment or on product surfaces have the ability to embed within a biofilm. Once formed, bacteria embedded within a biofilm may employ quorum sensing as a method of perceiving nutrient availability and communicating between other bacterial cells. Products flowing over surfaces containing biofilms cause sloughing off of pathogens or spoilage organisms embedded within biofilm and result in the cross-contamination of dairy products.
Session 37, Biofilms in the food industry: Problems and solutions
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