## 4 Discussion
The total amount of microscopic fungi in bee pollen on the day of collection (after 5 h) was similar to the previous results of studies by [PERSON] and [PERSON] [44], in which the contamination of fresh pollen after 9 h was from 4.5 \(\times\) 10\({}^{3}\) to 9.5 \(\times\) 10\({}^{3}\) cfu g\({}^{-1}\). [PERSON] et al. [45] also performed a fungal colony count in fresh bee pollen, which varied from 560 to 37,000 cfu g\({}^{-1}\) and was significantly (\(p\) < 0.01) higher than the fungal colony count in dried pollen. In our study, the amount of fungi in different periods varied depending on storage duration time. Fresh bee pollen stored for different time periods showed that the amount of fungi started to increase with longer duration of pollen storage. The highest amount of fungi (7.2 \(\times\) 10\({}^{3}\) cfu g\({}^{-1}\)) was determined after 3 days of storage duration of fresh pollen, however, according to scientists from the International Honey Commission (IHC), this amount of fungi failed to exceed the limits of recommended quality criteria (<5 \(\times\) 10\({}^{4}\) cfu g\({}^{-1}\)) [46]. In this study, the genus _Fusarium_ was detected in less than half of fresh pollen samples tested. _Fusarium_ fungi can survive as saprotrophs and require more than 20% substrate moisture to develop and multiply [5]. According to frequency, among all identified fungi _Fusarium_ spp. was the fourth. [PERSON] et al. [45] found _Fusarium_ spp. to be the second most frequently encountered microscopic fungi in dried bee pollen, but no _Fusarium_ fungi were detected in fresh bee pollen. According to the data by [PERSON] et al. [16], the _Fusarium_ spp. was rarely detected in dried bee pollen. In the study by [PERSON] et al. [2], _Fusarium_ occurred mostly in dried bee pollen. _Fusarium_ is the main toxin-producing genus among fungi [10]. Many toxic species of the genus _Fusarium_ are widespread in all European cereal growing areas, including Lithuania [47]. Isolates of _Fusarium_ species were isolated in the pollen in order to elucidate the producers of fusariotoxins. Six species of the genus _Fusarium_ were detected in 21 samples. Similar results (five species) were obtained by other researchers [17]. In this study, _F. graminearum_ was clearly predominant in the period of all studies (1-3 days). _F. graminearum_ is known as the most common _Fusarium_ species and the producer of deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN) [19; 48]. The next dominant species were _F. sporotrichoides_. [4], _F. sporotrichoides_ and _F. verticilioides_, which dominated in the study of [PERSON] et al. [17]. However, in our study the contamination level of _F. verticilioides_ was generally low, especially at the end of the storage (Figures 1 and 2). Based on other research [17], _F. oxysporum_ was one of the prevailingspecies, comprising 55.6%. In our study, the amount of _F. oxysporum_ isolates was low, and on average comprised 14.19%. Other species, _F. culmorum_ (11.18%) and _F.poae_ (10.78%), were also less common. In the PCA it was found that _F. poae_ was closely related to three storage days duration when at that time the amount of _F. poae_ increased. (Figure 2). The production of mycotoxins depends on a number of factors, such as temperature, humidity, substrate composition and the quantity of fungal inoculum. A long period between collection and drying of pollen can also affect the growth of toxigenic fungi and the production of mycotoxins [49]. The increase in mycotoxins after 3 days showed that the temperature of 22-25 \({}^{\circ}\)C and the moisture of the substrate may be favourable for the growth and development of _Fusarium_ fungi. The increases found in _F. graminearum_, _F. sporotrichoides_ and _F. culmorum_ during this period are possibly related to the highest levels of zeanalenone (ZEN) and deoxynivalenol (DON) released. PCA analysis indicates the strongest correlation between the colony forming units of _F. graminearum_ the concentration of DON and ZEN at the end of the storage (Figure 2).