D2.211 - Fungal Contamination in Coffee Grounds: A Case of IgE-Mediated Allergy

Coffee-related allergic reactions are rare and may involve contaminants rather than coffee itself. Fungal proteins from species like Aspergillus fumigatus and Penicillium notatum have been identified as potential allergens in occupational and environmental exposures. This study investigates a case of allergy to contaminated coffee grounds.

A 49-year-old male with moderate persistent asthma reported exacerbations triggered by exposure to coffee grounds, particularly when contaminated ("green dust"). The patient also showed sensitization to common aeroallergens, including Dermatophagoides, Phleum pratense, and pet epithelia, though these were clinically less relevant. Skin prick tests were positive for coffee grounds and fungi. Symptoms improved when coffee exposure was avoided.

Protein extracts were prepared from contaminated and uncontaminated coffee grounds, Aspergillus fumigatus, and Penicillium notatum. SDS-PAGE and Western blot analyses were performed to assess allergenic profiles. IgE reactivity was evaluated using patient serum.

Western blot revealed IgE binding to a high molecular weight protein (75 kDa) in the contaminated coffee grounds, absent in the uncontaminated sample. Additional IgE reactivity to a 25–37 kDa protein was observed in the Aspergillus fumigatus extract. No significant IgE binding was detected in the Penicillium notatum sample, suggesting distinct allergens from fungal contamination.

This case highlights the role of fungal contamination in coffee grounds as a trigger for allergic reactions. The identified proteins indicate sensitization to fungal allergens rather than coffee itself. Comprehensive allergenic profiling is essential for accurate diagnosis and management, especially in individuals with occupational or environmental exposures.