Anti-biofilm activity of cinnamon bark oil emulsions with biosurfactant or Tween 80 against Candida tropicalis on food-contact surfaces

Abstract

Candida tropicalis, isolated from juice ultrafiltration units, forms biofilms with tolerance to sanitizers and is a concern in beverage processing. This study evaluated the anti-biofilm activity of cinnamon bark essential oil emulsions (CBE) stabilized with Tween 80 (CBE-TW) or a biosurfactant (CBE-BS) produced by Lactiplantibacillus plantarum Tw226. Emulsions showed bimodal distributions with Z-averages of 122.5 ± 0.6 nm (CBE-TW) and 453.9 ± 5.14 nm (CBE-BS) after 28 days, and destabilization signs after 14 days of storage at 25 ◦C. The emulsions were diluted at a concentration equal to the minimal inhibitory concentration (MIC), twice (2MIC) andhalf of the MIC (½MIC) to treat C. tropicalis 24 h biofilm performed on polyvinylidene fluoride membranes (PVDF-M) and stainless steel (SS). For CBE-TW no viable cells were detected at MIC or 2MIC, regardless of the surface; at ½MIC, cell viability decreased by 40% and 20% on PVDF-M and SS, respectively. For CBE-BS, on PVDF-M, no viable cells were detected at MIC and 2MIC, while a 32% reduction was observed at ½MIC. On SS, reductions of 20% and 6% were obtained at MIC and ½MIC, respectively, and no viable cells were detected at 2MIC. Overall, the results obtained under laboratory conditions suggest that CBE is a promising natural hygiene agent for food-contact surfaces.