Radiation decontamination of dry chamomile flowers and chamomile extract

Chamomile flowers show very high microbiological contamination, up to 108 microorganisms per gram. It is demonstrated that about 2% of thermoresistant bacteria survive to chamomile tea, and about 3% of sporogenic bacteria survive the extraction with aqueous ethanol. Commercial concentrated chamomile extracts also contain a high level of microbial contamination which persists for a long time. The presence of microorganisms in herbs and extracts presents a health hazard and can cause the spoilage of food. For radiation decontamination of concentrated chamomile extracts higher doses are required than for dry chamomile flowers. The components of ethereal oil and hydrophilic components obtained from irradiated dry flowers did not change up to a 10 kGy dose. No immediate radiation-induced change of the components obtained from concentrated extract was observed at 15 kGy, except for a 17% decrease of herniarin. However, for commercial sterility, lower doses would be adequate. The content of en-in-dicyclo-ether decreased only over an extended storage time. Radiation is an efficient and convenient method for decontamination of dry plants and the only choice for decontamination of heat-sensitive extracts and concentrates. (author)