Ethylene Oxide and 2-Chloroethanol in Foods: Hazards, Detection Markers, and Regulatory Perspectives.

Ethylene oxide (EO) has re-emerged as a major food safety concern, with findings in spices, sesame, dried vegetables, food additives, and composite foods revealing persistent gaps between toxicological hazard, analytical detectability, and regulatory interpretation. In current food control practice, 2-chloroethanol (2-CE) is often the dominant analyte because parent EO is highly volatile and reactive; however, the scientific basis for treating 2-CE as a surrogate for EO remains contested. This review examines EO-related residues through three integrated lenses: the chemistry and toxicological significance of EO and its reaction products, the analytical determination and interpretation of residues across food matrices, and the international regulatory divergence that hinders harmonization. Evidence indicates that EO itself is a compound of clear toxicological concern, whereas 2-CE is better understood as a policy-relevant marker of EO-related chemistry whose meaning depends on matrix context, processing history, and regulatory purpose. Processed and composite foods intensify this challenge by weakening the link between analytical findings and source attribution. Overall, EO is not simply a residue monitoring issue but an interpretive problem created by the misalignment of hazard assessment, marker-based analytics, and regulatory decision-making. Progress will require clearer toxicological positioning of 2-CE, matrix-specific analytical reporting, structured source attribution frameworks, and closer alignment between national control systems and international standard-setting efforts.