5-hydroxymethylfurfural in bee feed

Abstract

Classical beefeed is a concentrated sucrose solution that has to be freshly prepared by the beekeeper. Commercial bee feeds are invert sugar or starch syrups with added fructose that prevents cristallisation and keeps the bee feed fit for use for a longer period of time. During recent years, maximum levels of 5-hydroxymethyl-furfural (“HMF”), a conversion product of fructose are increasingly discussed. A comprehensive literature evaluation revealed that studies of the past were limited to a few publications on caged bees and that below 150 mg HMF/kg feed no adverse effects on bees were observed. In own outdoor trials under bee keeping conditions up to 150 mg HMF/kg of a fructose/invert sugar mixture were well tolerated. It can be assumed that the HMF tolerance of a feed depends on environmental conditions as well as the overall bee feed digestibility. From these data, no need for setting maximum levels of HMF in bee feed can be derived. The HMF content of bee feed increases temperature-dependent during storage and feeding. A limit between 20 and 40 mg HMF/kg feed syrup would prompt reformulations to ensure its compliance throughout the chain from production to the time of exposure to the bee. Accompanying measures (temperature control) would be needed throughout the chain. Reformulated bee feeds would need to be tested in pre-market trials under practical conditions in all European bee keeping climates to safely exclude other potential adverse effect of currently not predictable variables.