A comparison of vegetable leaves and replicated biomimetic surfaces on the binding of Escherichia coli and Listeria monocytogenes

Abstract

Biofouling in the food industry is a huge issue, and one possible way to reduce surface fouling is to understand how naturally cleaning surfaces based on biomimetic designs influence bacterial binding. Four self-cleaning leaves (Tenderheart cabbage, Cauliflower, White cabbage and Leek) were analysed for their surface properties and artificial replicates were produced. The leaves and surfaces were subjected to attachment, adhesion and retention assays using Escherichia coli and Listeria monocytogenes. For the attachment assays, the lowest cell numbers occurred on the least hydrophobic and smooth surfaces but were higher than the flat control surface, regardless of the strain. Following the adhesion assays, using L. monocytogenes, the Tenderheart and Cauliflower biomimetic replicated leaves resulted in significantly lowered cell adhesion. Following the retention assays, White cabbage demonstrated lower cell retention for both types of bacteria on the biomimetic replicated surface compared to the flat control surface. The biomimetic surfaces were also more efficient at avoiding bacterial retention than natural leaves, with reductions of about 1 and 2 Log in L. monocytogenes and E. coli retention, respectively, on most of the produced surfaces. Although the surfaces were promising in reducing bacterial binding, the results suggested that different experimental assays exerted different influences on the conclusions. This work demonstrated that consideration needs to be given to the environmental factors where the surface is to be used and that bacterial species influence the propensity of biofouling on a surface.