Clove, Cinnamon, and Peppermint Essential Oils as Antibiofilm Agents Against Alicyclobacillus acidoterrestris

<i>Alicyclobacillus acidoterrestris</i>, an acidothermophilic bacterium, is one of the main contaminants in the fruit industry due to its high tolerance to environmental stress and ability to form biofilms. As conventional methods of biofilm elimination may be ineffective, there is a need for safe and sustainable methods for <i>A. acidoterrestris</i> management. The objective of the study was to evaluate the antibiofilm activity of commercial essential oils derived from clove (<i>Syzygium aromaticum</i> (L.) Merr. & Perry), cinnamon (<i>Cinnamomum zeylanicum</i> Blume), and peppermint (<i>Mentha piperita</i> (L.) Huds.) against <i>A. acidoterrestris</i>. The effect of the essential oils on the mature biofilms of fifteen environmental <i>A. acidoterrestris</i> isolates subjected to variable pH values (3.0, 4.0, and 5.5), temperatures (25, 37, and 44 °C), and essential oil concentrations (0.5 MIC, MIC, and 2 MIC compared to planktonic cells) was studied. The essential oils showed significant antibiofilm activity against <i>A. acidoterrestris</i> isolates, with the efficiency of biofilm eradication depending on the strain and environmental parameters such as acidity, culture temperature, type, and concentration of essential oil. The greatest antibiofilm potential was observed for clove essential oil regardless of oil concentrations and environmental conditions. Cinnamon oil exhibited lower activity against the tested <i>A. acidoterrestris</i> strains. Peppermint essential oil showed the weakest antibiofilm ability and did not completely eradicate any strain biofilm of the tested strains. Clove and cinnamon essential oils have the potential to be effective alternatives to synthetic disinfectants directed against <i>A. acidoterrestris</i> grown in the form of biofilms.