Microbial and heavy metal contamination in commonly consumed traditional Chinese herbal medicines

AbstractObjectiveThe increasing popularity and widespread use of traditional Chinese herbs as alternative medicine have sparked an interest in understanding their biosafety, especially in decoctions that are consumed. This study aimed to assess the level of microbial and heavy metal contamination in commonly consumed herbal medicine in Malaysia and the effects of boiling on these contamination levels.MethodsFour commonly consumed Chinese herbal medicine in Malaysia-“Eight Treasure Herbal Tea”, “Herbal Tea”, Xiyangshen (Radix Panacis Quinquefolii) and Dangshen (Radix Codonopsis) were evaluated in this study. Herbal medicines were prepared as boiled and non-boiled decoctions, and their microbial enumeration and heavy metal detection were conducted with plate assay and atomic absorption spectroscopy, respectively.ResultsFindings revealed that herbal medicines generally had 6 log10cfu/mL microbial cells and that boiling had significantly reduced microbial contaminants, where no Bacillus spp., Staphylococcus spp. and Clostridium spp. were recovered. Heavy metals such as Mn, Cu, Cd, Pb, Fe and Zn were also detected from all the samples, generally in low concentrations (