Fungal diversity in honeys from northwest Spain and their relationship to the ecological origin of the product

Abstract

Abstract The microscopic analysis of honeys has led to the identification of different structures, including pollen grains, fungal spores, yeast, algae and soot particles. Pollen grains are the most studied elements, while others, like fungal spores and yeast, are less well known. Some of these elements come from primary sources and are associated with the presence of honey dew, such as Alternaria, Stemphylium, and Leptosphaeria. A variety of yeasts are regularly present in the floral nectar of many plant species where they frequently reach high densities. A melissopalynological method was used to identify some of these microscopic elements, their frequency in honeys and the relationships with the ecological origin of the product. The pollen types most frequently identified were Castanea sativa, Rubus, Cytisus type, Eucalyptus and Erica. Cladosporium conidia were identified in 64% of the samples, Metschnikowia cells were present in more than 50% of the honeys and some plant pathogenic fungi (Leptosphaeria, Stemphylium and Urediniospores among others) were also frequently present. The presence of Metschnikowia cells was associated with blossom honey and the presence of some fungal spores was associated with honey dew contributions.