Dried figs: an example of food that, if not properly dried or stored, can be at risk of ochratoxin contamination, a mycotoxin produced by certain molds. - © Freepik

Published on 25 January 2025 on The history of coffee
by Fabio Arangio

What is Ochratoxin: The Limited Risk in Roasted Coffee

Coffee is much more than just a drink, it is the ritual that marks the start of the day, a moment of pause, and often also an opportunity to share – today we might even say connection – with others. How many times have we heard or said the phrase: "Shall we have a coffee together?".

An action synonymous with sharing and conviviality, making coffee an indispensable companion in our daily lives.

Coffee, a safe food

Besides the pleasure it gives, coffee is also a safe food, as long as it is carefully monitored. Among the substances that could represent a risk is ochratoxin, a mycotoxin produced by certain types of molds. Although the risk is generally low, it is important to be aware of what it is and how it may affect the quality of our coffee.

What is ochratoxin?

Ochratoxin A (OTA) is a mycotoxin produced by fungi of the Aspergillus and Penicillium genera, which thrive under conditions of high humidity and moderate temperatures. These fungi can contaminate plant-based foods such as cereals, coffee, dried fruit, spices, and wine, as well as animal products if the animals have ingested contaminated food.

Chemical formula and structure

The chemical formula of ochratoxin A is C₂₀H₁₈ClNO₆. This molecule is characterized by the presence of an isocoumarin ring, a chlorine atom, and a derivative of the amino acid phenylalanine, which gives the substance a relatively stable structure. Chemical stability is one of the factors contributing to the persistence of ochratoxin in foods.

Health risks

Ochratoxin is considered a toxic and potentially dangerous substance for human health, especially if consumed in high amounts or over long periods of time.

Effects on kidneys: Ochratoxin is nephrotoxic, meaning it can damage the kidneys. Studies have shown that this mycotoxin is associated with a condition known as Balkan endemic nephropathy, a chronic kidney disease found in some regions of Europe.
Carcinogenic properties: It has been classified as possibly carcinogenic to humans (Group 2B) by the International Agency for Research on Cancer (IARC).
Effects on the immune system: Ochratoxin can interfere with the normal immune response, reducing the body's ability to fight infections.
Liver toxicity: Although less studied than its nephrotoxicity, ochratoxin can also damage the liver in cases of chronic exposure.

How can one come into contact with ochratoxin?

Exposure to ochratoxin mainly occurs through the consumption of contaminated foods. The foods with the highest risk include:

Cereals (wheat, barley, corn).
Coffee, especially green coffee if not stored properly.
Dried fruit and spices.
Animal products such as milk or meat, if the animals have ingested contaminated food.

Regulations and safety limits

To reduce the risk of exposure, the European Union has set maximum allowable limits for ochratoxin in foods:

In cereals: maximum 5 µg/kg.
In roasted coffee: maximum 5 µg/kg.
In instant coffee: maximum 10 µg/kg.

These regulations are accompanied by strict controls along the entire production chain to ensure that foods meet safety standards.

Ochratoxin and coffee: How it forms and how to avoid it

Ochratoxin A can form in coffee during several stages, mainly in cultivation, harvesting, and storage. The molds that produce this mycotoxin thrive under conditions of high humidity and moderate temperatures, typically between 20°C and 37°C. If coffee beans are stored in environments with humidity above 70% or exposed to rain during drying, the risk of contamination significantly increases.

Ochratoxin can contaminate plantations and develop when the coffee is still wet. However, it is almost entirely eliminated during the roasting process, being degraded by the high temperatures during coffee bean roasting. - © Freepik

How ochratoxin degrades in coffee

Fortunately, ochratoxin A is not resistant to high temperatures. During coffee roasting, which takes place at temperatures between 190°C and 240°C, a significant portion of ochratoxin is degraded. Approximately 50-70% of ochratoxin is destroyed during the roasting process, depending on the duration and temperature. Dark roast coffee, which undergoes longer roasting at higher temperatures, tends to have lower residual levels of ochratoxin compared to light roast coffee.

How to prevent ochratoxin formation in coffee

To avoid ochratoxin contamination, it is crucial to adopt preventive measures throughout the entire coffee production process:

Good agricultural practices in cultivation: Implement good agricultural practices such as well-ventilated plantations and timely harvesting of beans to reduce the risk of molds.
Effective drying: Beans must be dried quickly after harvesting, preferably on dry surfaces with direct exposure to the sun, ensuring a final moisture content of less than 12%.
Storage in healthy places: Store green coffee in cool, dry environments with humidity below 65% and temperatures below 20°C to prevent mold growth.
Monitoring and control: Regularly monitor coffee samples for the presence of ochratoxin and intervene promptly in case of contamination.

Thanks to these practices and modern processes, the risk of ochratoxin in consumed coffee is very low. Serious and responsible roasters like Il Caffè Manaresi carefully monitor every stage of production to ensure that every cup of coffee is not only delicious but also safe.

Our Quality Guarantee

At Il Caffè Manaresi, we are committed to offering a product of the highest quality and absolute safety. That is why every year we subject samples of green coffee, roasted coffee beans, and ground coffee to rigorous laboratory analyses to verify the absence of ochratoxin. This allows us to guarantee coffee that is not only delicious but also safe for all our customers.