Long-term microbiological and chemical changes in bee pollen for human consumption: influence of time and storage conditions

Abstract

In order to evaluate if bee pollen properly processed could be conserved for more than 12 months without suffering alterations on its microbiological and chemical qualities, 48 dried bee pollen samples from Argentina were stored at room (23 ± 2 °C) and at refrigerated temperatures (4 °C) during two years. The microbiological (culturable heterotrophic mesophilic bacteria, yeasts and filamentous fungi, Enterobacteriaceae, coliforms, spore-forming bacteria, Salmonella sp., Escherichia coli, Staphylococcus aureus and Clostridium perfringens) and chemical qualities (moisture, pH, ash, proteins and carbohydrates) of three samples from each treatment were evaluated every three months over two years. In bee pollen samples, human pathogenic bacteria were not detected. In general, the count of yeasts, culturable heterotrophic mesophilic bacteria and filamentous fungi were statistically lower at room temperature compared to refrigerated temperature over the storage period. Aerobic spore-forming bacteria populations did not show significant changes at the different storage periods neither at room nor at refrigerated temperatures. The protein and the ash content did not differ while carbohydrate content, moisture and pH changed over the storage period. The results show that microorganisms do not multiply in dried bee pollen although they can be present after a long period of storage at both studied temperatures. Bee pollen has maintained its microbiological and chemical qualities for more than six months at both temperatures, however, at room temperature, its sensory properties were altered after nine months from the beginning of the storage. The shelf life could be longer if it was preserved at fridge temperature.