Irradiation, EtO not permitted for supplement sterilization, clarifies BI

By Lorraine Heller

- Last updated on GMT

Related tags Dietary supplement

Botanical ingredients supplier BI Nutraceuticals has sent its customers a clarification of current US regulations that prohibit the use of irradiation and ethylene oxide (EtO) as a means to sterilize supplement ingredients.

The Californian firm, which has developed an alternative dry steam sterilization process, said many dietary supplement manufacturers may not be aware of the regulations, and may therefore unwittingly be using adulterated materials in their products.

A consultative article commissioned by the company examines the “enormity of the sterilization issue facing dietary supplement manufacturers”​. It provides references to the US Food and Drug Administration (FDA) regulations that prohibit the use of irradiation and EtO as means to reduce microbial loads in botanicals.

“With respect to sterilization of dietary ingredients and supplements, there are a limited number of options,”​ said Loren Israelsen, director of the supplement trade group Utah Natural Products Alliance (UNPA).

“Irradiation and ethylene oxide are not among them,”​ the article quotes him as saying.


The irradiation process exposes foods to ionizing radiation that kills insects, moulds, and up to 99 per cent of pathogens. Although upheld by many as a safe process, the regulatory story on irradiation is inconsistent across the globe.

In the US, FDA is currently clarifying its position on the issue, but in the interim the process is prohibited.

In comment 292 to FDA’s preamble to the final cGMP ruling for dietary supplements, published in 2007, the agency writes: “We are not adding ‘irradiating’ to the list of practices [to prevent the growth of microorganisms] because, at this time, irradiation of dietary ingredients and dietary supplements, as a means to reduce or eliminate microbial loads, is not permitted.”​ Click here​ to access the full comment.


The common fumigant ethylene oxide has been prohibited for years in the United States.

The Federal Food, Drug and Cosmetic Act (FFDCA) states that foods containing pesticide chemical residues beyond established tolerance levels are considered adulterated.

CFR 180.151 sets an EtO tolerance level for whole and ground spices of 50 ppm. However, because herbs are not considered spices, this tolerance level does not apply to them, meaning that any herb treated with EtO is adulterated, explained BI Nutraceuticals.

Alternative sterilization methods

A number of alternative sterilization processes have been developed as alternatives to the use of irradiation and EtO. These include high heat, ozone, hydrogen peroxide, and steam sterilization.

However, according to BI, “nearly all”​ of these techniques have “significant drawbacks”.

“Subjecting an herb to high heat can burn it, discolor it, or flash off the volatile oils. Ozone, a powerful oxidizing agent, can chemically alter the antioxidant profile of a plant. And hydrogen peroxide is not widely commercially available,”​ stated the company’s article.

Dry steam sterilization

BI is promoting its proprietary steam sterilization process as the industry’s only species-specific, organic steam sterilization method.

The Protexx HP system, which took three years to develop, uses super-heated dry steam to reduce microbiological load in raw materials. BI said this yields results comparable to treating ingredients with ethylene oxide or irradiation, “but without the potential regulatory issues”.

The company has been using this sterilization process for around six years. It said it has over 700 species and genius specific computer protocols to sterilize its botanical ingredients. These controls allow it to sterilize its ingredients without affecting volatile oils and color integrity, it explained.

At the end of last year, BI expanded its steam sterilization capacity through the addition of a second unit at its headquarters in Long Beach, California. A third unit is located at BI’s processing facility in Suzhou, China.

The expansion is expected to allow it to sterilize more than 15,000 metric tons of herbal botanical, spice and food ingredients annually.

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