The effect of gamma radiation on the microflora and essential oil of Ashanti pepper ( Piper guineense) berries

The optimal gamma radiation dose capable of eliminating the natural microflora of Ashanti pepper without adversely affecting the flavour qualities was investigated. The prevalent micro-organisms were Clostridium, Staphylococcus, Bacillus, Aspergillus and Fusarium species. Both ground and whole forms of Ashanti pepper were subjected to 0, 2.5, 5.0, 7.5 and 10.0 kGy doses of gamma rays from a 60Co source. The 2.5-kGy doses reduced the fungal and bacterial load by 2 log cycles and 7.5 kGy eliminated the fungal population. A dose of 10 kGy was required to decontaminate the samples irrespective of sample form, although grinding and not irradiation affected the essential oil composition of the spice.