Contamination of honey by oxytetracycline from pig manure.

Although the use of antimicrobial is not allowed in bee industry according to current EU legislation, antimicrobial residues are often detected in honey doomed to human consumption. This study aims to investigate if bees living in hives located nearby tanks filled with pig manure containing residues of oxytetracycline, would naturally harvest water from it, thus contaminating their honey. Data from this experiment were compared with those originating from direct contamination with oxytetracycline through the beehive feeders. Bees did not harvest water from manure, even during the warmest days of summer. Instead, antimicrobial residues were evidenced and quantified in honey from hives directly contaminated with oxytetracycline. Interestingly, antimicrobial residues were also observed in honey from untreated hives thus suggesting that illegal treatments can cause contamination, albeit at low levels, of honey produced in legally-untreated neighboring hives.