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Response surface model for the reduction of Salmonella biofilm on stainless steel with lactic acid, ethanol, and chlorine as controlling factors

Zhang, Qiu Qin, Ye, Ke Ping, Juneja, Vijay K., Xu, Xinglian
Journal of food safety 2017 v.37 no.3
Salmonella, antimicrobial properties, biofilm, chlorine, disinfectants, equipment, ethanol, exposure duration, lactic acid, models, regression analysis, stainless steel, synergism
A disinfectant containing chlorine (Cl), ethanol (EtOH), and lactic acid (LA) was investigated to reduce Salmonella biofilm on stainless steel. The present experiment was employed with disinfectants: Cl (50, 100, 150 ppm), LA (1, 2, and 3%), EtOH (10, 20, and 30%) and exposure times (ET; .5, 2, 3.5 min). A response surface model developed to predict the reduction of Salmonella biofilms was found to be significant (p < .0001) with a regression coefficient of .8019 and an insignificant lack of fit (p = .364). Interaction of ethanol with other variables resulted in a significant reduction of Salmonella biofilm. As compared to Cl and EtOH, Salmonella biofilms showed low sensitivity to LA. Extending ETs showed a significant positive effect on Salmonella biofilm reduction. The antimicrobial effect of mixed disinfectants depended on ET. Therefore, Cl, EtOH, and LA can be used in a mixture to achieve a synergistic effect and can potentially remove Salmonella biofilms. PRACTICAL APPLICATION: This study was undertaken to assess and quantify the efficacy of combinations of various concentrations of chlorine, lactic acid, and ethanol in eradicating the formed biofilms of Salmonella on a stainless steel surface. Chlorine acidified with lactic acid and then, added to ethanol‐based disinfectants can be effectively used to reduce Salmonella biofilms on stainless steel equipment. The reduction of Salmonella biofilms on stainless steel as treated with the mixed disinfectants can be estimated by the quadratic model developed in the present study.