oxalic acid / varroosis / honeybee / honey / residues Tests on the use of oxalic acid for controlling varroosis (Takeuchi et al, 1983; Zjuman, 1987;Radetzki et al, 1994;Nanetti et al, 1995;Imdorf et al, 1997) Bee mortality was determined using 'underbasket traps' applied to each hive (Accorti, 1994).The mean efficacy of the three treatments with oxalic acid was 95% (± 7.39%) (

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Antibacterial drugs are used worldwide for the control of American and, less often, European foulbrood. Their administration is mostly uncontrolled and applied without approved protocols and instructions for use as well as precautionary recommendations. Consequently, this practice is responsible for the contamination of beehive products and contributes to the problem of food safety. According to this situation, 4672 analyses were carried out on 5303 honeys collected from 2001 to 2007. These samples were investigated for antibacterial residues of tetracyclines, sulphonamides, streptomycin, chloramphenicol and tylosin. Honeys were classified according to their origin: imported honey and honey from the Italian market. In the last group (only for samples collected from 2001 to 2004), another type of honey was distinguished: that of local honey. A total of 6.3% of all samples were positive for the antibacterial drugs analysed; in particular, 6.8% of imported honeys and 6.1% of honeys on the Italian market. Only 1.7% of local honey had antibacterial residues. These results are indicative of a rather frequent presence of antibacterial drug residues in both Italian and imported honeys. Furthermore, the data showed that among the active substances analysed, sulphonamides are the most used antibacterial substance followed by tetracyclines, streptomycin, tylosin, and chloramphenicol. Finally, a continuous monitoring programme is needed, accompanied by an education programme to beekeepers on proper hive management.

This study was performed to evaluate the distribution and depletion of sulfathiazole in different beehive matrices: honey, honeybees, "pre-existing" honeycomb, "new" honeycomb, and capping wax. Sulfathiazole was dissolved in sugar syrup or directly powdered on the combs, the matrices were sampled at different time points, and sulfathiazole residues were quantified by high-performance liquid chromatography with fluorescence detection. In honey, the higher concentration of sulfathiazole (180 mg kg(-1)) occurred 2 weeks after the last treatment in syrup. In beeswax, drug concentration was higher than in honey, particularly with powder administration, with a maximum level (340 mg kg(-1)) 3 days following the last treatment. The strongest contamination in honeybees (28 mg kg(-1)) was achieved with sulfathiazole administered in powder 3 days after the second treatment. The high persistence of sulfathiazole in the different beehive matrices suggests that it could be a reliable marker of previous treatments performed by beekeepers.