The Diversity of Yeasts in Beekeeping Environments and the Selection of a Culture Starter for the Development of a Mead

Abstract

The biodiversity of several beekeeping environments and honey samples was studied. The bacterial and yeast counts ranged from 0.00 to 5.19 Log CFU/g and from 0.00 to 3.33 Log CFU/g, respectively, presenting significant differences between the values. Of the honey samples, two of them exceeded the legislative limit established for total aerobic bacteria (5.19 Log CFU/g and 5.03 Log CFU/g). A total of ninety-eight yeast strains were isolated, with eight different species: Candida albicans, Dekkera anomala, Zygosaccharomyces rouxii, Z. mellis, Kazachstania unispora, Meyerozyma guillermondii, Saccharomyces cerevisiae, and S. unisporus. This implies a low microbial biodiversity and a low genetic variability index (D = 0.116 and 6–19%, respectively) due to the large number of genetically identical individuals found in each species. To select the most adequate strains for mead elaboration (with pure and mixed cultures), the fermentation capacity and organoleptic characteristics were studied. The best yeasts were chosen for the “pure culture fermentation” of honey (Saccharomyces spp. M11A2) and for mixed sequential inoculation (K. unispora M17A2). Both of the yeasts were isolated from honey and selected for their high fermentative capacity and resistance to ethanol. The results of the sensory analysis of the meads that were produced, in addition to one commercial product, were compared and indicated that the one inoculated with the pure culture had the best overall impression.

Keywords

• beekeeping environments
• yeast microbiota
• bacteria and yeast counts
• mead