Sucrose Laurate as a Biofilm-Modifying Adjunct for Cleaning-in-Place Chemical Control of Escherichia coli K-12...

Biofilms on food processing surfaces can persist despite cleaning and sanitation, creating a need for adjunct strategies that improve biofilm control without replacing existing cleaning-in-place systems. This study evaluated sucrose laurate (SL), a sugar-based fatty acid ester, as a biofilm-modifying adjunct for selected CIP-related chemicals against Escherichia coli K-12 biofilms. The MICs of SL, sodium hypochlorite (NaOCl), sodium hydroxide (NaOH), phosphoric acid (H₃PO₄), and nitric acid (HNO₃) were determined by broth microdilution, and biofilm inhibition and eradication of preformed biofilms were assessed using static 96-well microplate assays with crystal violet staining. SL showed limited planktonic inhibition, with an MIC greater than 5000 µg/mL, whereas the MICs of NaOCl, NaOH, H₃PO₄, and HNO₃ were 62.5 µg/mL, 1250 µg/mL, 2500 µg/mL, and 2500 µg/mL, respectively. SL did not reduce the MICs of the tested CIP-related chemicals. However, SL strongly inhibited biofilm formation at concentrations far below its planktonic MIC, reducing residual biofilm biomass by more than 90% at 50 µg/mL and 25 µg/mL. In contrast, SL alone showed limited eradication of preformed biofilms, indicating that its activity differed between biofilm formation and established biofilm biomass. In combined biofilm inhibition assays, fixed low concentrations of SL (6.3 µg/mL and 12.5 µg/mL) enhanced biofilm inhibition under selected combined treatment conditions, and the response varied by CIP-related chemical and concentration. In eradication assays, SL fixed at 2500 µg/mL supported selected CIP-related treatments, with NaOCl-SL combinations maintaining residual biofilm biomass near the blank-corrected baseline and NaOH-SL combinations generally reducing residual biofilm biomass to approximately 10 to 15% of the untreated control. These findings suggest that SL functions as a biofilm-modifying adjunct rather than as a strong planktonic antibacterial agent against E. coli K-12.