The Microbiological Quality of Herbal Teas and Herbal Medicinal Products

Plant material are used throughout developed and developing countries as home remedies, over the counter drug products and raw materials for the pharmaceutical industry and represent a substantial proportion of the global drug market. Medicinal plant materials normally carry a great number of bacteria and moulds, often originating in soil, while a large range of bacteria and fungi form the naturally occurring micro flora of herbs, aerobic spore-forming bacteria frequently predominate [1].

Eighty five herbal teas and sixteen herbal medicinal products obtained from different suppliers were examined for microbial contaminants. The maximum acceptable limits were determined according to European pharmacopoeia [2]. The microbiological examination was carried out in accordance with the Ph.Eur. The total aerobic plate counts for herbal teas were about 10⁵ CFU/g, so the limits were met. The same applied to the moulds and yeasts whose aggregate values reached 10⁴ CFU/g. While none of the herbal tea samples contained Salmonella spp., six samples exceeded the limit of 10² CFU/g for E. coli.

The total aerobic plate counts for herbal medicinal products were about 10² CFU/g.

References: [1] Beckmann, K. et al. (2003) Pharmeuropa 15: 291–298. [2] European Pharmacopoeia. (2005) Council of Europe. Strasbourg.