About this Research Topic
Coffee processing is common throughout the world. Workers engaged in this industry are exposed to a complex mixture of gases, dusts, and vapors including carbon monoxide, carbon dioxide, coffee dust, allergens, alpha-diketones, and other volatile organic compounds (VOCs). Adverse respiratory health outcomes such as symptoms, decreased pulmonary function, asthma, and obliterative bronchiolitis can occur among exposed workers. Obliterative bronchiolitis has been found among workers exposed to alpha-diketones (diacetyl and 2,3-pentanedione) present in flavorings in food processing, flavoring-manufacturing, and among coffee processing flavoring-room workers. Additionally, processing of non-flavored coffee can also generate exposures to diacetyl and 2,3-pentanedione. Exposures above the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limits and short-term exposure limits have been reported for processing flavored and non-flavored coffee. The exposure limits are intended to keep the excess risk of workers' lung function falling below the lower limit of normal caused by diacetyl or 2,3-pentandione exposure to 1/1,000 after 45 years' exposure.
NIOSH conducted health hazard evaluations at 17 small- to medium-sized coffee processing facilities during 2016 -2017, and additional data were available on engineering controls evaluations and serial spirometry tests from workers. The broad objectives of these investigations were to understand the burden of respiratory abnormalities, exposure to alpha-diketones, risk of adverse respiratory health effects related to exposures and options for exposure mitigation.
This Research Topic is a comprehensive reporting of the findings of NIOSH investigations in a series of papers addressing the exposure to disease pathway and approaches to prevention. The conceptual framework for conducting these investigations, including strategies for exposure and health assessment, will be described. Instantaneous, short-duration, and full-shift exposure to alpha-diketones and other VOCs and their associations with tasks, jobs, and processes will also be described. The variability in these exposures will be evaluated through mixed-effects regression modeling to identify and prioritize intervention strategies. The prevalence of respiratory symptoms and pulmonary function abnormalities will be summarized, including performing cluster analyses on health outcome variables to identify groups of workers with patterns consistent with obliterative bronchiolitis, asthma, or other underlying respiratory disease. In addition, an illustrative case report of severe lung disease in a worker from a flavoring room will be presented. Exposure-response relationships of the multiple health outcomes with exposure surrogates such as tasks, jobs, or proximity to different processes will be explored through linear, binomial, or multinomial regression models, while the relationships with quantitative exposure to multiple alpha-diketones will be evaluated statistically using multi-pollutant models that account for collinearity. To explore the effects of engineering control interventions and the utility of serial spirometry as a surveillance tool, two separate case studies will be presented that describe the efficacy of different control measures and the value and limitations of serial spirometry. To close this series, a perspective on the impacts of risk assessment assumptions related to alpha-diketones will be presented.
This is comprehensive, multi-disciplinary research aimed at understanding the burden and risk of adverse respiratory health outcomes among coffee processing workers, and identifying effective strategies to mitigate exposures in this industry.
Keywords: alpha-diketones, coffee processing, diacetyl, engineering controls, obliterative bronchiolitis, 2, 3-pentanedione, respiratory effects
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