Microbiological Quality, Antioxidative and Antimicrobial Properties of Slovenian Bee Pollen

Abstract

Bee pollen can be considered as perfect food with a great nutritional value, highprotein and essential amino acid content, vitamins and minerals. It can be a sourceof healthy nutrients, but as an animal product also of harmful microbialcontaminants. The aim of our study was to determine potential health risks andbenefits of Slovenian bee pollen. We determined its i) microbiological burden:aerobic mesophilic microorganisms, yeast, molds, and coliform bacteria in CFU/g;ii) polyphenolic content: the Folin-Ciocalteu method (mgGA/g); iii) antioxidativepotential (AOP): DPPH• scavenging assay (EC50 in mgGA/L); and iv)antimicrobial activity (MIC): microdilution method on Escherichia coli, Listeriamonocytogenes and Campylobacter jejuni. We analyzed 14 samples of bee pollengathered from 7 Slovenian geographical regions, from April until May 2017. Themicrobiological burden was high, with all indicator tests reaching up to 6.78log10CFU/g of bee pollen, but the number of coliform bacteria in all samples from2.00 to 4.48 log10CFU/g. The polyphenolic content and AOP of the samples wasgood, with up to 13.1 mg GA/g and as low as 2.4 mgGA/L (EC50), respectively.Interestingly, antimicrobial activity was not always in correlation withpolyphenolic content, but always strongly against E. coli, substantial against C.jejuni, and negligible against L. monocytogenes. Our results show a great healthpotential of bee pollen for human health, but also the need of bee pollen processingimprovement for its standardized quality and safety.

Bee Bread Exhibits Higher Antimicrobial Potential Compared to Bee Pollen

“…Moreover, some authors observed contradictory results, e.g., the group of Ivanisova who investigated antibacterial potential of Ukrainian BB [ 45 ]. The outcomes of some investigations suggest that method of extraction, such as solvent, can importantly affect different aspects of biological properties of produced extracts, including antimicrobial activity [ 46 , 47 , 48 ].…”

Screening of Plant Pollen Sources, Polyphenolic Compounds, Fatty Acids and Antioxidant/Antimicrobial Activity from Bee Pollen

“…After this suspension was mixed thoroughly, 100 µL samples from the second wells were transferred to the third wells and these procedures were repeated until the last well (8th well). Thus, starting from the first well, the BCPE concentration was diluted by half in all wells consecutively [ 52 , 67 ].…”

Antimicrobial Activity of Bee-Collected Pollen and Beebread: State of the Art and Future Perspectives

“…One reason is that after evaporation of the initial solvent, the remaining dry matter is often dissolved in another solvent which is not the same in all studies. Such solvents might be dimethyl sulfoxide (DMSO) [ 47 , 166 ] or ultrapure water [ 73 ]. Therefore, one should take into account the particular chemical and physical effects of used solvents on the bacterial cell membrane system.…”

“…This comparison might define the optimum antimicrobial activity against certain pathogens among diverse samples (botanical/geographical origin) or different extraction methods. It seems that Gram-positive bacteria are in general, more susceptible to BCP [ 46 , 47 , 50 , 126 , 154 , 165 , 172 ] with some noticeable exceptions [ 156 , 163 , 166 ].…”

“…Nevertheless, in some studies, the same BCP sample may be more effective against either Gram–positive or Gram–negative bacteria depending on the used solvent during extraction, as previously mentioned. Authors reported that Gram–negative bacteria ( E. coli and C. jejuni ) were more sensitive against Slovenian BCP extracts ( Table 3 ) than Gram–positive bacteria ( L. monocytogenes ) [ 166 ]. Also BCP extracts from Chile exhibited antibacterial activity against S. pyogenes I.S.P.…”