Efficacy of plant-derived compounds combined with hydrogen peroxide as antimicrobial wash and coating treatment for reducing Listeria monocytogenes on cantaloupes

The efficacy of four plant-derived antimicrobials (PDAs), namely carvacrol, thymol, beta-resorcylic acid, and caprylic acid, with or without hydrogen peroxide (HP), as antimicrobial wash and chitosan based coating for reducing Listeria monocyto genes (LM) on cantaloupes was investigated. Cantaloupe rind plugs inoculated with LM (10(7) CFU/cm(2)) were washed for 3, 6,10 min at 25 degrees C or 1, 3, 5 min at 55 or 65 degrees C in water, or water containing 2% PDAs with or without 2% HP. Additionally, inoculated cantaloupes (10(8) CFU/fruit) washed with 2% PDA-HP combinations at 55 or 65 degrees C (5 min) were cut into rindless cubical pieces, stored at 4 degrees C for 7 days and sampled for LM. Furthermore, inoculated plugs coated with 2% PDAs were stored for 7 days and sampled for surviving LM. Individual PDA washes reduced LM on rinds by >= 2.5 log CFU/cm(2) by 3 min (P < 0.05). PDA-HP combinations decreased LM to undetectable levels by 5 min at 55, 65 degrees C, and 10 min at 25 degrees C (P < 0.05) and reduced LM transfer from cantaloupe surface to interior (P < 0.0001). All PDA coating treatments reduced LM on cantaloupe to undetectable levels by 5 days (P < 0.05). Results indicate that PDAs alone, or with HP could be used to reduce LM on cantaloupes. (C) 2014 Elsevier Ltd. All rights reserved.