Antimicrobial activity of organic honeys against food pathogenic bacterium Clostridium perfringens

Against Clostridium perfringens, a common cause of food poisoning, antimicrobial activity and methyglyoxal (MGO) contents of six multifloral organic honeys were investigated, five from Finland and one from Argentinian and Hungarian origin. For the antimicrobial assessment, a disc diffusion method was used with zone of inhibition expressed as a diameter. Four honeys had inhibitory activity (diameter >8 mm) compared to control (diameter of 6.1 mm ± 1.5) at the concentration of 50 % (w/v). The highest activity was induced by North Carelien multifloral honey F with willow herb as the main floral source (diameter of 14.3 mm ± 0.6), followed by other North Carelien multifloral honey E (diameter of 11.0 mm ± 2) with clover as the main floral source. For honey F, the minimal inhibitory concentration (MIC) was 20 % (w/v). MGO was quantified by HPLC and varied from 22 to 27 mg/kg. MGO had no correlation to the detected activity. This is a novel finding on the antibacterial activity of native organic honeys and against C. perfringens. © 2015, The Author(s).