Workers in the coffee industry, especially those engaged in the roasting and grinding of the green coffee beans, may at times be exposed to an inhalant allergen. The source of this allergen is the castor bean.
In Central and South American countries, burlap bags are used in the transport of the large crop of castor beans. These contaminated bags may later be used also for the transport of green coffee beans. Thus, the allergen becomes an accidental contaminant of the green coffee beans.