Studies on the microbial decontamination of Egyptian bee pollen by γ radiation

Abstract

Objective Bee pollen are used as health food ingredients, but may be subjected to microbial contamination; γ radiation technology can offer the process of microbial decontamination as a means of achieving microbiological safety limits. Materials and methods Thirty bee pollen samples were collected from Egyptian markets. Detection of contamination and the microbial counts were carried out on nutrient and Sabouraud’s agar media for bacteria and fungi, respectively, using the aerobic plate technique. Identification of bacteria was carried out by biochemical methods and analytical profile index. Moreover, identification of fungi was carried out morphologically and microscopically. Results and conclusion The order of bacterial contamination was Gram-positive rods>Gram-negative rods>Gram-positive cocci. The order of fungal contamination is Penicillium spp.>Aspergillus flavus>Aspergillus niger>Aspergillus ochracueus. Only three strains of A. flavus could produce aflatoxin B1. The microbial counts of bee pollen samples decreased with increasing γ radiation doses. The most radio-resistant bacteria that were isolated at 5.0 kGy were identified as Bacillus megaterium, Bacillus pumilis and Bacillus subtilis. The most radio-resistant fungi were identified as Penicillium chrysogenum, Penicillium expansum and Penicillium corylophilum. Using of γ radiation can decrease the bioburden in bee pollen, and eliminate pathogenic microorganisms including fungi, which can produce carcinogenic aflatoxins.