Single and Sequential Application of Electrolyzed Water with Benzalkonium Chloride or Peracetic Acid for Removal of Staphylococcus Aureus Biofilms

The effectiveness of electrolyzed water (EW) to remove biofilms formed on stainless steel by Staphylococcus aureus strains isolated from fishery products was assessed. The bactericidal activity of EW against biofilms was hardly any affected by any variations in the pH of production. Neutral EW (NEW) was therefore used in subsequent studies as it has a higher potential for long-term application than acidic EW (due to a lower corrosiveness and toxicity) and due to the higher yield rate of the production unit at neutral pH. The application of NEW caused a high reduction in the number of viable biofilm cells initially. However, a high available chlorine concentration (800mg/L) was needed to achieve logarithmic reductions (LR) demanded by the European quantitative surface test of bactericidal activity ( 4log CFU/cm2 after 5min). A double sequential application of NEW at much lower concentrations for 5min each allowed LR4log CFU/cm2 to be reached in most of the experimental range. Sequential applications of NEW and either benzalkonium chloride or peracetic acid (PAA) showed a similar effect, with PAA-NEW being most effective. The combination of NEW with other antimicrobial treatments can thus be an environmentally friendly alternative to disinfection protocols traditionally used in the food industry. Practical Applications Spain is the largest producer and the second largest consumer of seafood in the European Union, thus ensuring the safety of these products is of outmost importance. However, a high incidence of Staphylococcus aureus was recently found in fishery products marketed in Spain, which questioned the efficacy of disinfectants traditionally applied in the food industry. This study focused on electrolyzed water (EW) because it is an environmentally friendly, safe-to-use and relatively inexpensive option. The data obtained in this study demonstrated that the combination of neutral EW and other disinfectants resulted in an effective alternative to control the contamination of food-processing facilities by foodborne pathogens such as S.aureus.