KPC Products, Inc.
(U.S. Main Office)
16 Goddard
Irvine, CA 92618

Chinese herbs derive from natural plants. Like any plant material, herbs are vulnerable to mold and insect infestation, especially when stored in poor conditions. Mold or infestation can ruin a crop and mean a financial loss for a farmer of herbs. To counteract mold and infestation, many Chinese-mainland farmers fumigate their herbs with sulfur-based vapors. The resulting sulfur dioxide wipes out existing pathogens, bacteria and halts decay from insects and herbs, acting as a chemical preservative. The gas is able to reach even unexposed spaces.

The application of sulfur dioxide, however, alters the very nature of the herbs. Sulfur dioxide bleaches the herbs Dioscorea (shan yao), Pueraria Root (ge gen) and dried ginger (gan jiang).

KP opposes the use of sulfur dioxide in herbs because of the serious effects on the nature of Chinese herbs. Sulfur dioxide causes high sugar-content herbs, such as Cibotium (gou ji), becomes noticeably more acidic. Sulfur dioxide oxidizes herbs with fatty oils, such as Persica (tao ren), and gives them a pungent oily odor. Sulfur dioxide fumigation also damages the fundamental qualities of fragile herbs such as Chrysanthemum (ju hua).

Sulfur dioxide fumigation also produces some inorganic sulfites as a byproduct. For certain individuals, sulfites can cause adverse reactions and harmful side effects such as diarrhea, allergic reactions and asthma. KP takes actions to prevent sulfur fumigation from being applied to its raw herbs.

KP takes many precautions to keep sulfur fumigation from its herbs, because it can jeopardize the quality and safety of our herbal products.

KP's quality control teams analyze herbs for sulfur dioxide. KP employs the following methods aerated-oxidization, iodine titration, atomic absorption spectroscopy and direct color comparison. KP uses the Rankine method for sulfur dioxide residue analysis. In this method, the herbal sample is reacted with acid and then distilled. The sulfur dioxide is absorbed into the oxidized H202. The resultant sulfuric base is titrated with standard base. The resulting colors determine its sulfur content: olive green indicates no oxidized sulfur residue while a purplish-red color indicates a presence of oxidized sulfuric acid.