Food Grade Dye for Assessment of Biofilm Removal from Stainless Steel by Cleaning and Sanitizing Agents

The objective of this study was to evaluate a food grade dye, erythrosin B, for use in the development of a quantitative color difference methodology to measure the efficacy of cleaner/sanitizer solutions in removing biofilm components from stainless steel surfaces. Biofilms of Listeria innocua and Pseudomonas putida were grown on stainless-steel coupons, subjected to various cleaner/sanitizer treatments, and then stained with erythrosin B.Resultant coupons were photographed and meanL*a*b* color differences between background anddyed area evaluated. Color differences conformed to ascale correlated with human visual perception. Resultsindicated that the method provides sensitivity for visualappraisal of treatment-response as well as species-response relationships. The method shows potential asan enhancement for quantitative visual assessment ofcleaning/sanitizing treatments of biofilms in a laboratorysetting, and supplemental research is warranted toassess its efficacy for GRAS inspection of food processingenvironments as part of the Hazard Analysis Critical Control Point program.