title: Control of natural microorganisms in chamomile (Chamomilla recutita L.) by gamma ray and electron beam irradiation.
abstract: BACKGROUND
  Microbial contamination levels and corresponding sensitivities to gamma rays (GR) and elec- tron beam (EB) irradiation were tested in chamomile (Chamomile recutta L.).
  
  
  METHODS
  Chamomile powders were treated with 10 and 20 kGy by GR and EB, respectively. Microbiological and chemical analyses were performed on controls and treated samples immediately after irradiation, and after 12 months of storage.
  
  
  RESULTS
  The control samples of chamomile exhibited rather high microbiological contamination, exceeding the levels of 4 log10 CFU g-1   (CFU - colony forming units) reported by national and international authorities as the maximum permissible total count level. Irradiation with GR and EB was found to cause a reduction in microbial contamination proportionate to the dose delivered. The sterilizing effect of EB on microorganisms was higher than the GR one. A dose of 10 kGy of GR and EB significantly (p < 0.05) reduced the total bacte- rial, total coliform and total fungal contamination. A dose of 20 kGy of GR significantly (p < 0.05) reduced the total bacterial and total fungal contamination, while a 20 kGy dose of EB reduced the initial bacterial, total coliform and total fungal contamination to below detection level when the analysis was carried out im- mediately after irradiation treatment or after 12 months of storage.
  
  
  CONCLUSIONS
  The comparative study demonstrated that electron beam was more effective for decontamination of chamomile powder than gamma irradiation.
authors.affiliation: Radiation Technology Department, Atomic Energy Commission of Syria.
authors.forename: Mahfouz
authors.initials: M
authors.lastname: Al-Bachir
mesh_terms: D020843:Chamomile / Q000382:microbiology* / Q000528:radiation effects*; D015169:Colony Count, Microbial; D004307:Dose-Response Relationship, Radiation; D005514:Food Irradiation; D005516:Food Microbiology; D005720:Gamma Rays
keywords: chamomile; decontamination; electron beam; gamma ray; moisture storage