When either of the pure anhydrides, butyric or propionic, were added to honey in amounts up to 20 ppm, no anhydride could be seen in the subsequent ether extract analysed by gas chromatography. Thus while both of the anhydrides could be volatile enough in comparison with their acids, to reach the honey, they would be rapidly hydrolysed by water in the honey to leave their corresponding acids as residues. 

With the known breakdown of the reactive anhydrides in honey, it was decided that the possible compounds that would be found in honey as residues from the use of bee repellents could include: propionic acid from the use of propionic anhydride; butyric acid from the use of butyric anhydride (Bee Go); benzaldehyde and/or benzoic acid from the use of benzaldehyde, and phenol from the use of phenol. 

Phenol use resulted in phenol residue levels from 0·6 to 14·8 ppm (average 6·6 ppm) in collected honey samples with levels of phenol varying in a manner consistent with earlier findings (Daharu & Sporns, 1984a). That is, higher phenol levels occurred in honey collected from uncapped regions with small amounts of honey in the cells (larger amounts of surface area per unit honey collected). 

Benzaldehyde use left undetectable residue levels of benzaldehyde (the ubiquious benzoic acid was still present) in collected honey samples. Bee Go use resulted in undetectable residual butyric acid levels except for two honey samples of 1·7 and 5·2 ppm from one of the hives (Table 3). Propionic anhydride use resulted in propionic acid residue levels of from 1·1 to 24·4 ppm (average 7·9 ppm) in collected honey samples. 

Finally, it is felt important to comment on potential consumer concerns of the bee repellent residues that were found in honey. Benzoic acid is found naturally in honey and other foods and is a common antimicrobial food additive. Propionic acid is also used as an antimicrobial food additive and is found naturally in many foods, such as Swiss cheese, which can contain up to 1% propionic acid by weight. 

Butyric acid is naturally found in foods such as butter and cheese at much higher levels than any that we detected in honey samples. Phenol, although not a toxicological concern at the levels found in honey, does affect the flavour of honey (Daharu & Sporns, 1985) and the use of phenol as a bee repellent is not recommended by agencies such as the Environmental Protection Agency in the United States. 

Suet Kwan & Peter Sporns (1988) Analysis of Bee Repellents in Honey,
Journal of Apicultural Research, 27:3, 162-168

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