Contamination of beeswax
Over the past year, articles dealing with the falsification of wax have frequently been published in the specialist press. The damage includes the collapse of combs, patchy brood patterns on newly built combs, and bees becoming trapped during emergence. The cause of these problems is the addition of stearin, paraffin, or other organic substances. Pesticide residues can also cause damage. As is known from experience with mothballs, there is likewise a risk that undesirable chemical additives in the wax may later appear in the honey.
Adulteration
The addition of stearin and/or paraffin to pure beeswax has become common practice. Both substances are used in the production of inexpensive candles. Stearin is obtained by saponification of palm oil and animal fats. It is a mixture of palmitic and stearic acids—acids that are also natural constituents of beeswax. Paraffins are saturated hydrocarbons composed of 18 to 32 carbon atoms. They are petroleum-based and exhibit a range of properties. If long-chain molecules predominate, the melting point is higher; conversely, if short-chain molecules are more abundant, they melt at lower temperatures. The wax scales produced by bees also contain hydrocarbons. In recent years, the price of beeswax has increased sharply on the global market. It is therefore financially very attractive to dilute it with low-cost products. Analyses carried out by the Apicultural Health Service in Aulendorf (Germany) show, in cases of adulteration (mixtures of pure beeswax with stearin and/or paraffin), a shift in the quantitative ratios of oleic, stearic, and palmitic acids. The first three columns show results from wax produced by the bees themselves (via their wax glands) and therefore free of foreign substances. Traditionally blended wax from Germany shows a similar fatty acid pattern. By contrast, a foundation sheet that caused brood damage after being drawn by bees, and two samples of wax from China, display significant deviations likely resulting from adulteration.
Contamination
Various lipophilic substances accumulate in wax. Given that pesticides are often lipophilic, suspicious samples were analyzed accordingly. Twelve different pesticides were identified in the sample of foundation sheets that had caused brood damage within the colony. Five of these are highly toxic to bees, two moderately so. The sample also contained four acaricides. Concerning quantities of degradation products of amitraz were detected in both samples of wax from China. Amitraz is used worldwide to control varroa. This substance is prohibited in Switzerland. In addition, three other acaricidal substances were identified. Unfortunately, wax analyses are costly and cover only a limited spectrum of substances; they therefore never reveal all impurities that may be present in wax. In autumn 2016, during the congress of German-speaking apicultural advisors in Europe at the Rottaler Bienenhof in Bayersbach (Germany), the apparently complex issue of wax adulteration was discussed in depth.
Damage
The following symptoms were observed, individually or in combination, in cases of wax adulteration:
- wax with an unusual structure resembling fruit pomace
- wax that turns brownish when heated
- collapsed combs
- extremely patchy brood—up to 90%—on new frames, while brood is compact on older frames of the same colony
- bees trapped during emergence
As with the many possible forms of wax adulteration and contamination, the symptoms observed in colonies are also diverse. However, it should be noted that patchy brood is not solely the result of poor-quality wax, but also—and often—an indication of disease, cannibalism (in cases of food shortage), food storage (especially pollen) in the brood nest, or diploid drone larvae (double chromosome set as a consequence of inbreeding). Dark discoloration of wax may also result from overheating (particularly with solar wax melters) or from contact with base metals.
In summary
There are numerous ways to adulterate pure beeswax. Determining the causes of the resulting problems is very difficult. For this reason, beekeepers must do everything possible to avoid any potential impairment of wax quality. When purchasing foundation sheets, it is essential that manufacturers and suppliers are trustworthy. They have a duty to continuously monitor the origin and properties of the wax.
See also:
- Beeswax – composition and properties
- Wax hygiene: a key factor in colony health
- Six good scientific reasons not to use old frames
- Recycling and purifying wax in beekeeping