Control and elimination of biofilm formation in the food processing environment is vital for food safety. This study was designed to investigate the efficacy of hydrogen peroxide (H2O2) pre-treatment combined with the regular daily cleaning procedure used in a shrimp plant to control biofilm formation. Single and mixed species biofilms of Listeria, Salmonella and Pseudomonas were used as the test model. Single biofilms on stainless steel (SS) coupons were formed under nutrient stress and harvested at 3 and 7 days to assess four cleaning procedures. Using 2% alkaline detergent for 10 minutes followed by two types of quaternary ammonium compounds (QACs) - based sanitizers completely eliminated single biofilms of Listeria and Salmonella. When alkaline was replaced to acidic type, microbial reduction achieved 5 log colony forming units (CFU)/cm2 (or more). For the mixed species biofilm study, biofilms were formed under the simulated seafood processing plant conditions for 7 days, on SS, Teflon and rubber coupons. After pre-treated mixed species biofilms with H2O2 at 1% and 2% for 5 and 10 minutes followed by the regular cleaning procedure, 2% of H2O2 for 10 minutes reduced microorganisms by 6 log CFU/cm2. Mixed biofilm on SS was easier to remove compared to the other surfaces. Overall these results suggest that the application of H2O2 prior to the regular cleaning process in food processing facilities may help to reduce and control biofilm formation, particularly biofilms composed of mixed species.

Keywords: Biofilm, Listeria, Salmonella, Pseudomonas, hydrogen peroxide, cleaning, sanitizer, stainless steel, Teflon, rubber