The Microbial Quality Aspects and Decontamination Approaches for the Herbal Medicinal Plants and Products: An in-Depth Review

Abstract

The present review article provides an overview of the published literature concerning microbial quality of medicinal plants and products and their decontamination methods. It is important to analyze different aspects regarding the cultivation, growing, harvesting, storage, manufacturing, and decontamination of medicinal plant products. Herbal medicinal plants bear a massive microbial load leading to contamination and mycotoxin, which needs to be considered, and properly controlled using suitable sterilization and decontamination methods. The main focus of this review is on the definition, advantages, disadvantages and applications of decontamination methods, particularly to show that one must consider the characteristics of the initial sample to be decontaminated. The effects of various methods (ozone, plasma, irradiation) on medicinal herbs and products treated for microbiological decontamination are dependent on factors related to microbial load (i.e., nature and amount of initial contamination), herb/product matrix (i.e., complexity of chemical composition, physical state - solid or liquid) and treatment conditions (i.e., time, irradiation dose, absence or presence of oxygen). In addition, it is important to accept some loss of the chemical compounds, while decreasing microbial load to acceptable limits according to official herbal pharmacopoeias and literature, thus ensuring a final product with quality, safety and therapeutic efficacy. The conclusion, which comes from this contribution, is that herbal medicine has more contaminants than a chemically welldefined drug, thus, good manufacturing practices should be followed.