When diacetyl and 2,3 pentanedione (a diacetyl substitute) was tested for in the air at a small coffee roasting plant, the levels were shockingly high, according to a study published last year by Toxicology Reports, an online journal.
According to the study, green unroasted coffee beans contain little to no diacetyl or 2,3-pentanedione. It’s the roasting process that plumes the toxicity into the air, and if a facility doesn’t have proper ventilation, the concentrations could prove to be health-damaging.
A second study published by Toxicology Reports by some of the same authors simulated a coffee-shop setting where the exposure to both the barista and consumers were tested. The focus was on the potential risk for customers who linger in coffee shops for long periods of time, either for social reasons or while using laptops.
Diacetyl is a chemical that occurs naturally in many foods and beverages, such as butter, yogurt, some fruits and vegetables, beer, wine, coffee and milk. According to the U.S. food and Drug Administration (FDA), the chemical is safe when consumed in trace amounts, but many studies, including the ones published by Toxicology Reports, indicate it may be toxic to inhale.
At the small coffee plant tested, the beans that were roasted had no added flavors. Many flavorings for coffees and e-cigarettes are known to contain diacetyl and 2,3 pentanedione, and are considered to be respiratory hazards for workers in the food industry.
One health risk of breathing diacetyl or 2,3 pentanedione is the development of obliterative bronchiolitis, better known as “popcorn lung” for the five microwave popcorn plant workers that developed the lung disease about 15 years ago. It is a disease where the smallest airways of the lungs become scarred and restricted. The symptoms include shortness of breath and a cough, and are very similar to the symptoms of COPD. The only treatment is a lung transplant.