Ethylene Oxide Residues

Scope and Objectives

AOAC INTERNATIONAL is responding to a challenging analytical method by forming a scientific initiative called ETO or the Ethylene Oxide Project. Introduced through the AOAC Analytical Science Forum, ethylene oxide is an emerging topic that was identified as a priority. Prior to launching the new project, AOAC conducted an interest survey focused on target matrix categories and main challenges related to analysis. After clarifying the challenges, an advisory panel was formed representing the food, dietary supplement, technology provider, and testing lab industries. This Advisory Panel empowered a new Working Group to develop an AOAC Standard Method Performance Requirements (SMPRs®) based on objectives and priorities established by the advisory panel, based on the industry need.

Ethylene oxide is a colorless, flammable, and highly reactive gaseous substance historically used in the food industry as a fumigant because of its capability to disinfect without the use of heat treatment; high diffusivity and strong penetrating properties; control of bacteria, fungi, and viruses, and effectiveness in dry food commodities. Main commodities include spices, nuts, oil seeds, dried fruits and vegetables, and dried herbs and botanicals. However, use of ethylene oxide has been discontinued in most parts of the world due to its highly toxic nature. The International Agency for Research on Cancer (IARC) classifies it as a group I carcinogen (carcinogenic to humans). Maximum residue levels (MRLs) vary for different commodities, and regulations differ among countries. Use of ethylene oxide as a fumigant has been banned in the European Union since 1991.

Some methods are available, such as direct, conversion, and chromatographic separation and detection, but are limited in scope. Analytical challenges include analyte volatility, matrix complexity, sensitivity, and selectivity, among others. Certified reference materials or proficiency testing schemes are not available for direct analysis.

Workstream

In developing draft SMPRs®, the working group reached consensus that methods are needed for determination of ethylene oxide and its marker residue 2-chloroethanol (analyzed and reported as a sum expressed as ethylene oxide) with limits of quantitation (LOQs) meeting EU and other global regulations in the following targeted matrices: oil seeds and nuts; dried herbs and spices; spice, flavor, and herbal extracts; food additives; dietary supplement products and ingredients; and dried fruits and vegetables. Methods are intended to be used as global reference methods for surveillance and monitoring by trained technicians. As recommended by the working group, methods using chromatographic separation with mass spectrometric detection are preferred but, ultimately, it is open to the method developer(s).

Get Involved

With the publication of the completed standard, we invite organizations to review the published standard in preparation for the Call for Methods phase. This new standard will drive support of regulatory compliance and provide the analytical basis for development of new testing methods.

Published SMPR®

The Ethylene Oxide Working Group has published the following SMPR®.

AOAC SMPR® 2024.005
Standard Method Performance Requirements (SMPRs®) for Determination of Ethylene Oxide and Its Marker Residue 2-Chloroethanol in Oil Seeds and Nuts, Grains, Pulses, Dried Herbs, Spices and Extracts Thereof, Food Additives, Dietary Supplement Products and Ingredients, Dried Fruits, Essential Oils, Coffee, Cocoa and Composite Foods

Ethylene Oxide Article in March/April 2024 of AOAC’s Inside Laboratory Management magazine

AOAC would like to thank the following Ethylene Oxide Working Group Contributors