Chestnut honey as a complementary medicine: determination of antibacterial activity, heavy metal residue and health risk assessment

In this study, residue levels for heavy metal content and antimicrobial effects of 30 chestnut honey samples obtained from member beekeepers of Yalova Bee Association are examined. After 30 honey samples are digested under high temperature and pressure in a microwave oven, their Arsenic (As), Lead (Pb), Cadmium (Cd), Mercury (Hg) limits are determined by using ICP-OES. By using Agar gel diffusion method, 19 of the honey samples' antibacterial activity is tested on strains of Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), E. coli O 157: H7, B.cereus (ATCC 6633), S.typhimirium (NCTC 12416) and L.monocytogenes (ATCC 7644). Arsenic, Lead, Cadmium and Mercury residue levels in all honey samples are determined to be below the designated limits by Turkish Food Codex Regulation (2011). The non-carcinogenic health risk associated with heavy metal contamination in honey is found to be very low. None of the 19 honey samples show antibacterial effect on strains of L.monocytogenes. However, at 100% honey concentration, in all 19 honey samples antibacterial effect is observed on strains of S.typhimirium, E. coli O 157: H7, except for only one honey sample; Escherichia coli and B cereus. The antibacterial activity on these bacteria is recorded to be maintained at 50% honey concentration. At 25% honey concentration, the antibacterial effect show a decline in most of the honey samples.