Chemical Varroa control is the most important contamination source for bee products as these chemical substances are repeatedly used. Only ecologically safe drugs as organic acids and thymol should be used. When applied properly, there are no problematic residues in bee products.
Testing for thymol residues in Swiss honey was carried out at the Centre for Bee Research as part of the apisuisse quality seal programme.
Among other things, thymol-containing preparations such as Api Life Var, Thymovar and Apiguard are used to control the Varroa mite. When these products are used according to the manufacturer’s guidelines, only minimal residues occur in the honey, and these do not influence its quality. When such products are used improperly, larger amounts wind up in the honey, negatively affecting its taste.
From a toxicological viewpoint, thymol is relatively unproblematic. Until 2009, a legal tolerance level of 0.8mg/kg honey applied in Switzerland. With harmonisation with EU law, this Swiss tolerance level was abolished. For beekeepers belonging to the quality seal programme, the maximum value of 0.8mg/kg stipulated by apisuisse still applies. In 2013, all ‘quality seal’ honeys met the requirements of the apisuisse quality seal in terms of thymol residues. A honey sample from a beekeeper not belonging to the quality seal programme contained over 0.8mg/kg thymol.
Influence of organic acids and components of essential oils on honey taste (PDF, 58 kB, 14.09.2016)
S. Bogdanov, V. Kilchenmann, P. Fluri, U. Bühler, P. Lavanchy (1998)
Thymol residues in wax and honey after Apilife VAR treatment (PDF, 757 kB, 14.09.2016)
S. Bogdanov, A. Imdorf, V. Kilchenmann (1998)
Determination of residues in honey after treatments with formic and oxalic acid under field conditions (PDF, 240 kB, 14.09.2016)
S. Bogdanov, J.D. Charrière, A. Imdorf, V. Kilchenmann, P. Fluri (2002)