|ZHANG, QUI QIN - Nanjing Agricultural University|
|YE, KE PING - Nanjing Agricultural University|
|XU, XINGLIAN - Nanjing Agricultural University|
Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2016
Publication Date: 12/15/2016
Citation: Zhang, Q., Ye, K., Juneja, V.K., Xu, X. 2016. Response surface model for the reduction of Salmonella biofilm on stainless steel with lactic acid, ethanol and chlorine as controlling factors. Journal of Food Safety. doi: 10.1111/jfs.12332.
Interpretive Summary: Salmonella, a deadly pathogen, that are attached to food and food contact surfaces or form biofilms can serve as the potential source of contamination of foods. We hypothesized that a low concentrations of a mixture of multiple disinfectants can be used to inactivate biofilm bacteria. This study was done 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. A predictive model developed for estimating the inactivation of Salmonella in biofilms can be effectively used to reduce Salmonella biofilms on stainless steel equipment. The results will be of immediate use to the food industry and regulatory agencies to ensure the safety of processed foods.
Technical Abstract: Bacterial colonization and biofilm formation on food contact surfaces can be sources of contamination of processed foods and poses a serious threat to health. Since chlorine- or ethanol-based disinfection is commonly used in the food industry and kitchens, a disinfectant containing chlorine (Cl), ethanol (EtOH) and lactic acid (LA) was investigated to reduce adhesion and biofilm formation of Salmonella on stainless steel. The present experiment was conducted with disinfectants: Cl (50, 100, 150 ppm), LA (1, 2 and 3%) and EtOH (10, 20 and 30%) and exposure times (ET; 0.5, 2, 3.5 min). Response surface methodology was applied to investigate the combined effect of four variables. A second-order response surface model developed to predict the reduction of Salmonella biofilms was found to be significant (p<0.0001) with a regression coefficient of 0.80 and an insignificant lack of fit (p=0.364). 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. These results indicated that Cl, EtOH, and LA can be used in a mixture to achieve a synergistic effect and can potentially remove Salmonella biofilms. The effect of various concentrations of Cl, EtOH, and LA on the reduction of Salmonella biofilms on stainless steel can be calculated by the model developed in this study.