Ochratoxin A is a mycotoxin that is possibly toxic to humans. Unfortunately, it is also found as a contaminant in many food items, including coffee. A mycotoxin is a metabolite produced by mold spores that may be present in the processing of many grains, fruits, and nuts. Exposure to ochratoxin A (OTA) by consumption of contaminated foods may cause direct damage to DNA. In addition, it is carcinogenic to the kidney. Therefore, it is beneficial to find methods to prevent or remove this contaminant from coffee and other foods.
Recently, a research team in Taiwan evaluated the plausibility of using wild yeasts to inhibit the germination of molds during the fermentation processing of coffee. Preventing the mold from forming and growing would prevent the metabolites from being produced. This would mean the finished coffee products would be free of OTA.
Yeast Conquer Mold
Coffee pulp is the primary bi-product of coffee processing and was selected as a substrate to simulate the fermentation process. The pulp was inoculated with various wild yeasts prior to fermentation. The idea is that metabolites of these yeasts may inhibit the germination of the mold spores. The various yeasts that were used also contributed to different scent profiles in the finished products. The optimum yeast will exhibit a high growth rate, so that the metabolite concentration produced will be enough to keep the mold in check, while at the same time also contributing to a pleasant aroma.
2 Strategies to Consider
It is noted that it is the metabolites, not the yeasts themselves, that are responsible for the inhibition of the mold. So there are 2 options apparent: addition of the live yeast to the fermentation, or simply addition of the metabolites to the fermentation. If the metabolites themselves can be added, then the selection of which yeast to use to ferment the coffee can be chosen for other factors such as taste and scent optimization.
Research into food processing and handling is important to prevent illnesses and long-term health effects caused by various contaminants. Because OTA is found as a contaminant in many foods, the metabolites discovered in this research may also find a use in the processing strategies for some other foods too.
Liu T, Hsu W, Lee B. Evaluation of the application of wild yeasts in inhibiting germination of ochratoxin-producing fungi during coffee fermentation process. Food Chem X. 2024 Dec 9:25:102077. PMID: 39758057