Control and elimination of biofilm formation in the food processing environment has remained a challenge for the food industry in terms of food safety.  This study was designed to investigate the efficacy of hydrogen peroxide (H₂O₂)pre-treatment in combination with the regular daily cleaning procedure used in the shrimp plant.  Single and mixed species biofilms of Listeria spp., Salmonella spp. and Pseudomonas spp. were used as the model. Single biofilm on stainless steel coupons (SS) were formed under nutrient stress and harvested at 3 and 7 days to assess four cleaning procedures.  The results showed that single biofilms of Listeria and Salmonella were completely eliminated by using 2% alkaline detergent for 10 minutes followed by two types of quaternary ammonium compounds (QACs), based sanitizers. This procedure could also eliminate Pseudomonas, by 3-4 log CFU/cm². However, to obtain a 5 log CFU/cm² (or more) reduction, this requires the replacement of acidic detergent. For the mixed species biofilm study, we used three types of materials, namely stainless steel, Teflon and rubber; biofilms formed under the simulated seafood processing plant conditions for 7 days.  We used H₂O₂ concentration of 1 and 2% for 5 and 10 minutes as pre-treatments for mixed biofilms prior to the regular cleaning procedure. Pre-treatment with 2% of H₂O₂ for 10 minutes reduced population of bacteria by 6 log CFU/cm².  No significant difference was found in pre-treatment of 2% H₂O₂ in 5 minutes and pre-treatment of 1% H₂O₂ in10 minutes. Furthermore, mixed biofilms on SS was easier to remove compared to the other surfaces.  Conclusion: The application of H₂O₂ prior to the regular cleaning process in food processing facilities may help reduce and control biofilm formation, particularly among mixed biofilm species.

Keywords

Biofilm, mixed biofilm, Listeria, Salmonella, Pseudomonas, hydrogen peroxide, cleaning process, stainless steel, Teflon, rubber