Biofilms in food processing environments

Biofilms are a constant concern in food processing environments. Our overall research focus has been to understand the interaction of factors affecting bacterial attachment and biofilm formation with the ultimate goal of devising strategies to control this problem. This paper briefly describes three areas of biofilm research in which we have been involved. Listeria monocytogenes, a foodborne pathogen, survived for prolonged periods on stainless steel and buna-n rubber, materials commonly used in food-processing equipment. Survival was affected by temperature, relative humidity, attachment surface, and soil. Some components in the rubber inhibited growth of the organism on buna-n, which also affected the efficacy of sanitizers on biofilm inactivation. In cheese manufacture, biofilms of Lactobacillus curvatus could lead to a defect caused by the formation of calcium lactate crystals in Cheddar cheese. This hardy organism persisted in low numbers on equipment surfaces and was difficult to eradicate. We investigated the relative contributions and interactions of mechanical, thermal, and chemical processes in an air-injected clean-in-place method for milking systems. Overall, it is important to study the interactions between bacteria and the surfaces in a specific food processing environment to provide more effective measures for prevention of biofilm formation and for its removal.