Microbial contamination of coffee during postharvest on farm processing: A concern for the respiratory health of production workers

Abstract

Coffee workers respiratory health problems, found to be associated with dust exposure in the coffee factories, but the content of the dust is not well known. A cross-sectional survey was conducted to assess the microbial contamination of coffee in dry and wet coffee process, from four farms in two regions of Ethiopia. A total of 36 samples of coffee were collected for laboratory investigation. The microbial load in the dry process ranged from 6.9 × 10² to 7.2 × 10⁵ colony forming units (CFU)/mL while the microbial load in wet process ranged from 2.5 × 10² to 4.6 × 10⁵ CFU/mL. The results indicate the presence of gram negative bacteria in dried and stored beans from both the wet and dry process. During further coffee processing possible release of endotoxin from coffee contaminated by gram negative bacteria might affect coffee workers respiratory health. Further studies are required to assess the relation between bacterial contamination of coffee and endotoxin level in coffee factories.

Keywords:

• Coffee
• gram negative bacteria
• postharvest Ethiopia
• endotoxin

Acknowledgments

We would like to thank the coffee preprocessing facilities management teams and Addis Ababa City Administration Health Bureau Laboratory for permission to conduct the study and allow us to use their laboratory.

Competing interest

The authors declare that they have no competing interest.

Additional information

Funding

This research was funded by the Norwegian Agency for Development Cooperation (Norad) through the Norwegian Program for Capacity Building in Higher Education and Research for Development (NORHED) through a research project “Reduction of the burden of injuries and occupational exposures through capacity building in low income countries” (project number: 1300646-12).