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Diacetyl: Inhalation of a GRAS Substance Not GRAS When It Came to Lung Disease

Updated: Feb 4, 2022

Nearly everyone knows how it feels to swallow a bite of food or sip of beverage that “goes down the wrong pipe”, what physicians call “pulmonary aspiration”. We cough, sputter, and turn red from the physical blockage and irritation. Food and food ingredients on a bulk scale (as food on the plate) are more healthful when eaten than when breathed.  Similarly, but on a less than bulk scale, airborne particles or molecules of a food ingredient that is Generally Recognized as Safe (GRAS) for consumption aren’t necessarily safe when breathed in. This is true for many food ingredient substances that are naturally volatile (such as fragrances and flavorings) or are handled in ways that promote volatility, such as spraying, harsh mixing (especially of dry powders), or heating to high temperatures.

How serious the differentiation between ingestion toxicity and inhalation toxicity can be started becoming apparent in May 2000 when a physician specializing in occupational medicine reported a cluster of eight cases of fixed obstructive airways disease to the Missouri Department of Health and Senior Services (MDHSS).1 All eight individuals had previously worked in the same microwave popcorn facility for periods ranging from 8 months to 9 years between 1992 and 2000.[1] All presented with respiratory illness consistent with bronchiolitis obliterans (BO)[2], a fixed obstructive airways disease that initially manifests as shortness of breath, coughing, and fatigue, but can produce fibrosis and obstruction of the small airways such that a lung transplant may be required. Four of the eight subjects in the physician’s report were on a waiting list for lung transplant; in response to the report, the MDHSS contacted the Center for Disease Control (CDC).

The initial findings of