Reduction of microbial contamination of nasturtium (Tropaeolum majus L.) by "mechanical saturated steam decontamination"

Taking nasturtium (Tropaelum majus L.) as example, a new and less stressful process of microorganism reduction in herbs and spices is presented. It is demonstrated that the mechanical saturated steam decontamination is a compound-friendly process for decontamination of medicinal drugs. This special method of saturated steam decontamination is characterized by the application of a vacuum accompanied by an explosion-like evaporation of a condensate film applied to the plant material. Due to this effect and in contrast to the usually applied saturated steam procedures with the thermal killing of the microorganisms naturally occurring on the plant surface, the microorganisms are mechanically removed by the mechanical saturated steam decontamination. It could be shown that this process of nasturtium treatment decreased the microbial drug contamination up to 4 decades, along with a small loss of glucotropaeoline of 13%.