Changes of microorganism composition in fresh and stored bee pollen from Southern Germany

Carolin Friedle,Paul D’Alvise,Karsten Schweikert,Martin Hasselmann,Klaus Wallner

doi:10.1007/s11356-021-13932-4

Carolin Friedle, Paul D’Alvise + Show 3 more

Open Access

https://doi.org/10.1007/s11356-021-13932-4

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Abstract

Analysis of plant pollen can provide valuable insights into the existing spectrum of microorganisms in the environment. When harvesting bee-collected pollen as a dietary supplement for human consumption, timely preservation of the freshly collected pollen is fundamental for product quality. Environmental microorganisms contained in freshly collected pollen can lead to spoilage by degradation of pollen components. In this study, freshly collected bee pollen was sampled at different locations and stored under various storage conditions to examine the hypothesis that storage conditions may have an effect on the composition of microorganisms in pollen samples. The samples were analyzed using 16S and 18S amplicon sequencing and characterized by palynological analysis. Interestingly, the bacterial communities between pollen samples from different locations varied only slightly, whereas for fungal community compositions, this effect was substantially increased. Further, we noticed that fungal communities in pollen are particularly sensitive to storage conditions. The fungal genera proportion Cladosporium and Mycosphaerella decreased, while Zygosaccharomyces and Aspergillus increased during storage. Aspergillus and Zygosaccharomyces fractions increased during storage at 30 °C, which could negatively impact the pollen quality if it is used as a dietary supplement.

Highlights

The existing spectrum of microorganisms in the environment can be revealed in pollen samples from plants (Anderson et al 2013; Manirajan et al 2019)
The microorganism composition in bee pollen is affected by plant source, geographical origin, and bee keeper activities (Nogueira et al 2012; De-Melo et al 2016)
We analyzed the botanical origin of the collected bee pollen samples

Summary

Introduction

The existing spectrum of microorganisms in the environment can be revealed in pollen samples from plants (Anderson et al 2013; Manirajan et al 2019). The male gametophyte of gymnosperms and angiosperms, represents the main protein and lipid source for honey bees (Apis mellifera). It provides a full spectrum of nutrients, mainly amino acids and lipids, and carbohydrates, minerals, vitamins, and enzymes Bee-collected pollen consists of pollen grains from flowering plants (including bushes and trees), as well as nectar and salivary secretion from the bees It is collected by foraging honey bees and transported to the hive in the pollen baskets known as corbicula on their hind legs (Kevan and Baker 1983; Willmer 2011). Bee pollen is perceived as a useful dietary supplement for humans, as it provides many necessary nutrients, especially a high amount of protein (± 20%) including essential amino acids like leucine, isoleucine, and valine, depending on the botanical origin (Paramás et al 2005; Carpes et al 2009; Martins et al 2011; Feás et al 2012; Nicolson and Human 2013; Taha et al 2019)

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