The food flavoring industry and flavoring chemicals have been under the scrutiny of National Institute for Occupational Safety and Health (NIOSH) for the last decade. Of particular interest is the use of diacetyl, or its substitute, 2,3 pentanedione, a flavoring that produces a buttery or creamy taste, put in a wide variety of products from bakery products, microwave popcorn, and coffee to e-cigarettes. NIOSH has even published a set of “best practices” guidelines for the chemical exposure.
The concern has been the potential respiratory damage linked to exposure to the chemicals. They are naturally produced during the coffee-roasting process, but it’s the grinding of the beans that create a much larger surface area for exposure during the off-gassing of the chemicals. Often, the roasted coffee is stored in hoppers for off-gassing, but the danger is prevalent when workers stick their heads into the hoppers to check the beans or inhale the aromas.
NIOSH recommended a diacetyl exposure limit for an eight-hour time weighted average (TWA) at 5 parts per billion, and short term exposure limit (STEL) at 25 ppb per 15-minute duration. At some coffee roasting facilities, the concentration near the roasting bins reached as high as 7,000 ppb.
Diacetyl has been heavily linked with a lung disease called bronchiolitis obliterans, which also became known as “popcorn lung” when several microwave popcorn workers exposed to excessive diacetyl developed the disease in 2000.
Bronchiolitis obliterans is a serious lung disease in which the smallest airways of the lungs become permanently blocked by excess scar tissue. It is often misdiagnosed as asthma, bronchitis, emphysema or even pneumonia because the symptoms are similar, with a patient coughing, wheezing, experiencing shortness of breath and fatigue. The only treatment for the disease is a lung transplant.