Purified avocado seed acetogenins: Antimicrobial spectrum and complete inhibition of <i>Listeria monocytogenes</i> in a refrigerated food matrix

<p>Avocado fruit contains lipid derivatives with antimicrobial properties called acetogenins. In this study, antimicrobial spectrum of purified acetogenins was characterized. Additionally, eight Gram-positive bacteria were exposed to commercial food preservatives (Nisaplin® and Mirenat®) for comparison. Acetogenins were also added to a food system containing meat, inoculated with <i>Listeria monocytogenes</i> and stored at 20°C and 4°C. Avocado seed extract (Avosafe®) contained 71.3% w/w total acetogenins, its main components were AcO-avocadene and persenone A (22.05 ± 1.84 and 20.14 ± 1.40% w/w, respectively). Avosafe® (15 µg disc<sup>−1</sup>) inhibited Gram-positive bacteria, with higher efficacy towards spore-formers (<i>Clostridium sporogenes, C. perfringens, Bacillus subtilis</i>, and <i>Alicyclobacillus acidocaldarius)</i>. Acetogenins’ inhibition zones were 2–4 times higher compared to Nisaplin® and Mirenat® for Gram-positive bacteria, except for <i>Staphylococcus aureus</i>. During refrigerated storage (4°C, 72 d), Avosafe® inhibited <i>L. monocytogenes</i> completely; decreasing initial 3-log inoculum to undetectable levels within 3 h, and maintaining the effect to completion.</p>