Clove Oil (<i>Syzygium aromaticum</i> L.) Activity against <i>Alicyclobacillus acidoterrestris</i> Biofilm on Technical Surfaces

Acidotermophilic bacteria <i>Alicyclobacillus acidoterrestris</i> is one of the main contaminants in the fruit industry forming biofilms which are difficult to remove from the production line by conventional methods. An alternative approach aims for the use of essential oils to prevent <i>Alicyclobacillus</i> biofilm development. The effect of clove essential oil on <i>A. acidoterrestris</i> biofilms on glass and polyvinyl chloride surfaces under static and agitated culture conditions was investigated by atomic force microscopy and the plate count method. The medium-flow and the type of technical surface significantly influenced <i>A. acidoterrestris</i> biofilm. The PVC was colonized in a greater extent comparing to glass. Clove essential oil in 0.05% (<i>v/v</i>) caused 25.1–65.0% reduction of biofilms on the technical surfaces along with substantial changes in their morphology by a decrease in the biofilm: height, surface roughness, and surface area difference. The oil also induced alteration in individual bacterial cells length and visible increase of their roughness. Clove essential oil seems to release EPS from biofilm and thus induce detachment of bacteria from the surface. Due to anti-<i>A. acidoterrestris</i> biofilm activity, the clove oil may be used in the juice industry to hinder a development of <i>A. acidoterrestris</i> biofilms on production surfaces.