The cleanability of laser etched surfaces with repeated fouling using Staphylococcus aureus and milk

Biofouling is a serious problem in the food industry, and one way to control biofouling is using topographically patterned surfaces. This in vitro study used a laser surface texturing process to produce six differently patterned topographies which were analysed for their topography and wettability with repeated fouling and cleaning. The surfaces were spray-inoculated with Staphylococcus aureus suspended in either sterile distilled water or whole milk, then spray-cleaned using a chlorinated, alkaline cleaner. The surfaces were cleaned up to 20 times and analysed for changes in their surface properties and biofouling. Analysis of Variance was used to assess the effect of the main factors and two-way interactions. Principal component analysis was used to discern underlying relationships. There were no significant differences (T-Tests) in the overall level of biofouling between the different rippled sub-textures. The spiked surfaces showed no overall increase in biofouling and the number of cleans but were predominantly influenced by the texture sub-type. The less regular spiked surfaces within the medium range showed the lowest levels of biofouling, even with repeated cleaning. This study demonstrated that the use of such surfaces in in vitro studies may reduce biofouling, but particular attention needs to be given to the surface design. (C) 2022 The Author(s). Published by Elsevier Ltd on behalf of Institution of Chemical Engineers.