Back Talk

How Clean Should Medicinal Herbs Be?

No retailer should have to worry that the medicinal herbs he sells could be contaminated with molds or illness-causing bacteria. Because there is no nationally recognized standard for microbial loads on raw botanicals, manufacturers must rely on their own standards or adhere to either the U.S. or European Pharmacopoeias. Yet there isn't even consensus among these published References. Valerian, for example, has separate sets of limits in the 1999 European Pharmacopoeia depending on whether it will be further processed (prepared with boiling water or extracted) or ingested directly. The 1999 U.S. Pharmacopoeia, on the other hand, currently has only one set of requirements for valerian. These particular microbial limits are so low that to meet them, the herb would have to be artificially sterilized.

"Many organizations are looking too closely at microbe counts. They're getting so caught up in low total plate counts that they're willing to do anything, including irradiation. I think this standard is coming from the pharmaceutical industry, where products are manufactured in laboratories. Of course those materials have incredibly low plate counts—they aren't products of the earth. Herbs are going to have bacteria and fungus and mold. I do not believe that medicinal herbs should be held to the standards of aspirin. It's absurd. Those kinds of demands are driving the irradiation industry. It is sad but true that irradiation is extremely pervasive in this industry."

Audrey Maxwell
Sales and Marketing Manager
Global Marketing
Hayward, Calif.

"The microbial limits for medicinal herbs in the European Pharmacopoeia and in the World Health Organization's (WHO) Quality Control Methods for Medicinal Plant Materials are appropriate. They wisely differentiate maximum limits for 'herbs for direct ingestion' from 'herbs that will be further processed.' In contrast, the current USP has unrealistically low microbial limits for raw herbs, which generally require sterilization by ionizing irradiation or ethylene oxide.

"Medicinal herbs that will be extracted with boiling solvents for fluid extracts or water for tea infusions do not require presterilization. If herbal products manufacturers purchase herbs according to European Pharmacopoeia or WHO standards, there is no need to presterilize raw materials, unless they are going directly into capsules. Ideally, herbs that do not meet these standards should be rejected rather than sterilized. Sterilization may also mask other purity problems resulting from poor agricultural and/or wild collection practices as well as poor postharvest drying, handling and storage conditions."

Josef Brinkmann
Research and Development Manager
Traditional Medicinals Inc.
Sebastopol, Calif.

"The United States Pharmacopoiea normally follows a two-tier approach: one for herbs directly consumed without further processing and another for herbs that are processed. Herbs that are consumed directly should have different microbial limits than those that will be processed, because those procedures are expected to take care of microbiological contamination.

"The limits set originally—for example, 10,000 colony forming units/g is the total aerobic count allowed for raw materials—have been objected to by the industry. Now we are revising that and proposing the level be raised to 10 million. For botanical extracts, we propose to keep the 10,000 limit. This does not require sterilization. We allow a generous aerobic count, but we cannot tolerate E. coli, for example. If it requires sterilization, then you better take care of it.

"We listened when people objected to our current stringent limits. USP proposed liberally relaxed limits in the Sept./Oct. 1999 Pharmacopoeial Forum. I don't believe the industry will object to them; however, there is a comment period. I expect an official standard will be adopted later this year."

V. Srini Srinivasan
Director for Dietary Supplements Division
United States Pharmacopoeia
Rockville, Md.

"Normal Microflora on dried foods and herbs are not associated with known health risks. Like food, good agricultural practices are vital to ensure an acceptable degree of cleanliness for botanicals. This degree depends on the herb, herb part and form and if it is intended for further processing. However, quality suffers if herbal material is contaminated or improperly dried. Sterilization may make herbs more sanitary but may also blind us to signs of previously mishandled material."

Steven Dentali, Ph.D.
Senior Director of Botanical Sciences
Rexall Sundown
Boca Raton, Fla.