Microbial Contamination in the Coffee Industry: An Occupational Menace besides a Food Safety Concern?

Area of Science:

• Industrial microbiology
• Occupational health
• Environmental science

Background:

• Respiratory issues are known in coffee processing, but internal microbial contamination is poorly understood.
• Assessing microbial load in coffee production facilities is crucial for worker safety and product quality.

Purpose of the Study:

• To evaluate fungal and bacterial contamination in two Brazilian coffee industries.
• To characterize microbial contamination using multiple sampling methods and molecular analyses.
• To identify toxigenic fungal species and assess antifungal resistance.

Main Methods:

• Multi-approach sampling: filtering respiratory protection devices (FRPD), settled dust, electrostatic dust cloths (EDC), and coffee beans.
• Microscopic identification of fungi and bacteria.
• Molecular detection (qPCR) of toxigenic Aspergillus sections.
• Antifungal resistance testing (itraconazole).

Main Results:

• Highest bacterial contamination found on FRPD (up to 7.45 × 10^4 CFU·m^-2).
• Aspergillus genera, including toxigenic sections (Nigri, Circumdati) and clinically relevant sections (Fumigati), were widespread.
• Antifungal resistance (itraconazole) observed in Aspergillus Circumdati.
• Discrepancies noted between microscopic and qPCR detection of Aspergillus sections.

Conclusions:

• Microbial contamination, particularly in the milling stage, represents a significant occupational risk.
• A comprehensive risk assessment requires multi-sampling strategies, including FRPD.
• High fungal diversity and contamination warrant consideration of occupational mycotoxin exposure.
• A One Health approach is recommended to manage fungal contamination and azole resistance in coffee production.