The American Herbal Products Association (AHPA; Silver Spring, MD) has published Limits of Foreign Matter in Herbal Ingredients, a new industry guidance outlining maximum quantities of foreign matter acceptable in selected herbal raw materials.
Herbal raw materials naturally carry foreign matter, and official pharmacopeias worldwide recognize quantitative limits as part of their herbal raw-materials monograph specifications. For example, explained AHPA in a press statement, the European Pharmacopeia monograph on “Hawthorn Leaf with Flower” caps levels of lignified branches with a diameter greater than 2.5 mm to not more than 8 percent of the material. Other matter subject to quantitative limits includes mineral mixtures not naturally present in the herbal raw material—soil or stones, say—and organisms or parts thereof not named in the specifications.
Maged Sharaf, PhD, chief science officer, AHPA, noted in the press statement: “Botanical ingredients are grown in nature where they are exposed to an array of foreign matter. This document recognizes this fact and helps the industry set acceptable limits for various types of foreign matter.”
These foreign-matter limits do vary among pharmacopeias—even for the same herbal material—and FDA has its own maximum levels of natural or unavoidable defects in foods that present no health hazards for humans. In its own guidance, AHPA recommends that plant parts of the same herbal raw material species other than those named in specifications should not exceed 5 percent by weight, and that all other foreign matter should not exceed 2 percent by weight.
AHPA states that the guidance offers “an overview of standard industry practices for the detection and mitigation of foreign matter and recommends good agriculture and collection practices.” Those GACPs are outlined in AHPA’s Guidance for Good Agricultural and Collection Practices and Good Manufacturing Practices for Botanical Materials, which further help minimize foreign matter in raw herbal materials.