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NCA Industry Resource Guide Diacetyl

NCA Industry Guide: Diacetyl


Diacetyl is a chemical compound formed naturally in the production of many foods and beverages, including milk, cheese, yogurt, coffee, citrus juices, vinegar, whiskey, wine – and coffee.

The compound is deemed safe for consumption by the U.S. Food and Drug Administration, which maintains that there is no evidence suggesting a hazard to the public as consumed. However, issues have arisen related to inhalation of diacetyl during food processing in the workplace.

Diacetyl & Worker Safety

Until recently, artificial diacetyl gave many processed foods a buttery flavor, and it’s still used in flavored e-cigarettes. After some workers manufacturing microwave popcorn contracted a rare lung disease, the compound caught the attention of journalists and regulators. A later case found similar claims among workers in a coffee flavoring room using aerosolized diacetyl.

The resulting coverage led to concerns about the small amount of natural diacetyl produced by roasting or grinding unflavored coffee. However, despite centuries of coffee roasting, there has never been a documented outbreak of lung disease among roasters. Today, modern roasting facilities are equipped to eliminate chemical compounds like diacetyl through closed roasting systems, ventilation, and other best practices.

Scientific evidence does not support a link between natural diacetyl exposure and lung disease. Independent research confirms that airborne concentrations of naturally occurring diacetyl in coffee processing “are far below the concentrations that are expected to cause even minimal responses in the human respiratory tract.”