Resilience to Climate Change by Biocontrol Yeasts Against Ochratoxin A Production in Robusta Coffee

Area of Science:

• Food Microbiology
• Plant Pathology
• Climate Change Adaptation

Background:

• Aspergillus carbonarius is a primary Ochratoxin A (OTA) producer in coffee.
• Yeast biocontrol agents are explored to mitigate OTA contamination during coffee postharvest processing.
• Climate change impacts on biocontrol efficacy against OTA-producing fungi are largely unknown.

Purpose of the Study:

• To investigate the impact of interacting climate change factors (temperature, CO2, water activity) on A. carbonarius growth and OTA production.
• To assess the resilience of yeast biocontrol agents under projected climate change scenarios.
• To identify the most robust yeast strain for biocontrol of OTA in coffee.

Main Methods:

• Examined the three-way interaction of temperature (27-33°C), water activity (0.90-0.95 aw), and CO2 levels (400-1000 ppm).
• Assessed A. carbonarius growth and OTA production under these conditions.
• Evaluated the biocontrol efficacy and resilience of three yeast strains on coffee cherries.

Main Results:

• Elevated temperature, water activity (0.95 aw), and CO2 (1000 ppm) significantly increased A. carbonarius growth and OTA production.
• All tested yeast strains reduced A. carbonarius growth by ≥20% and OTA production by up to 85%.
• Meyerozyma caribbica strain Y4 demonstrated superior resilience, reducing fungal growth by 50% and OTA by 70% under future climate scenarios.

Conclusions:

• Climate change factors exacerbate OTA contamination risk in coffee by promoting A. carbonarius.
• Yeast biocontrol agents offer a viable strategy to mitigate OTA, with M. caribbica Y4 showing strong resilience.
• M. caribbica Y4 is recommended for pilot-scale biocontrol experiments in regions like Ivory Coast.