Evaluation the inhibitory action of Egyptian honey from various sources on fungal and bacterial growth and aflatoxins production

Serial concentrations of three unprocessed honey (mountain; nuwara clover and citrus) samples from Egypt, were evaluated for their ability to act as antimicrobial activity against fifteen fungal species including toxigenic strains of Aspergillus flavus and A. parasiticus and four Gram positive and five Gram negative pathogenic bacterial isolates. Also, investigation of inhibitory action of aflatoxins production by A. flavus and A. parasiticus was studied. 90% and 100% concentrations of three honeys used, exhibited high ability to inhibit the growth of most of fungal and bacterial isolates. Mountain honey was the best honey. It showed antimicrobial activity followed by citrus then nuwara clover honey. However, 80% concentration from only mountain honey showed antimicrobial activity while all other honey concentrations prepared did not show any ability to reduce the growth of all fungal and bacterial isolates tested. As well as, no aflatoxins were produced at 100% concentration of three honeys used, while great reduction of aflatoxins production was detected after treatment with 90% concentration of all honeys. Moderated effect on toxins production was reported by 80% concentration and little inhibition was obtained at 70% honey concentration. Other honey concentrations (10% to 60%) showed opposite effect on aflatoxins production, where the amounts of toxins were increased. Mountain honey was the best, which showed ability to inhibit the production of aflatoxins by both of A. flavus and A. parasiticus followed by nuwara clover then citrus honey.