Mycotoxins In Coffee? Should I Be Concerned? 

mycotoxins in coffee beans and mycotoxins in coffee symptoms

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Did you know that your daily cup of coffee may contain mold toxins called mycotoxins?

Mycotoxins are toxic compounds produced by certain fungi or mold that can contaminate coffee beans. While coffee has many health benefits, the potential presence of harmful mold is concerning.

I know this is probably alarming news for any coffee lover to hear. But don’t toss out your coffee maker just yet! The amount of mycotoxins present can vary widely depending on factors like the coffee brand and bean processing method.

In this post, I’ll break down what exactly mycotoxins are, how they can end up in coffee, their associated health dangers, and actionable tips to reduce your exposure.

✔ Quick Answer

Mycotoxins in coffee are toxic compounds produced by certain types of fungi that can grow on coffee beans during cultivation, harvesting, or storage. These toxins, particularly aflatoxins and ochratoxin A, can pose health risks if consumed at high levels, making proper bean handling and processing crucial.

Let’s dive in!

What Exactly Are Mycotoxins?

When certain molds grow on agricultural crops, they can produce chemical byproducts called mycotoxins. These toxic compounds have the potential to contaminate our food supply and pose health risks. Coffee is one agricultural product susceptible to mycotoxin contamination.

There are many different types of mycotoxins, but the main ones that have been detected in coffee are ochratoxin A and aflatoxins

Ochratoxin A is produced by molds in the Aspergillus and Penicillium families, while Aspergillus molds generate various aflatoxins.

Together, ochratoxin A and aflatoxins make up the majority of mycotoxin presence in coffee beans and beverages.

What Exactly Are Mycotoxins: Photo of a modern coffee lab where a scientist is analyzing liquid samples from various coffee sources for mycotoxin content.

Numerous investigations have uncovered the presence of mycotoxins in both coffee beans, whether they are roasted or not, and in the coffee itself once brewed:

  1. Green coffee beans have been shown to harbor aflatoxins, with the highest concentrations found in decaffeinated varieties. The roasting process was found to decrease these aflatoxin levels by 42–55%.
  2. A study involving green coffee beans from Brazil discovered that 33% of the samples had trace amounts of ochratoxin A.
  3. Research analyzing coffee brews made from commercially available beans in Portugal revealed that 18% of the samples contained ochratoxin A.
  4. While 27% of roasted coffee samples were found to contain ochratoxin A, it is worth noting that significantly higher quantities were detected in chili products.

These findings underscore that a substantial portion of coffee beans and brewed coffee can contain mycotoxins.

Nevertheless, it is important to highlight that, according to a 2021 study, there is no historical data to conclusively state that ochratoxin A poses an acute toxic risk when consumed through coffee or other sources.

So while mycotoxin levels can vary, the potential for some degree of contamination exists in coffee. But what do these mold toxins actually do once consumed? 

Let’s look at how they can impact human health next.

The Dangers Of Mycotoxins On Human Health

Unfortunately, regularly consuming even small amounts of certain mycotoxins over an extended period can negatively impact health. 

The two main culprits when it comes to coffee are ochratoxin A and aflatoxins.

 Let’s look at what scientific research says about how these mycotoxins affect the body:

Ochratoxin A

Ochratoxin A has been shown to cause toxicity in kidney cells both in animal and human studies. Over time, exposure to ochratoxin A can lead to decreased kidney function, leaks in kidney filtration, and the formation of tumors.

The World Health Organization’s International Agency for Research on Cancer has classified ochratoxin A as a possible human carcinogen.


Of the aflatoxins, aflatoxin B1 is considered the most toxic. Aflatoxins target the liver and have been decisively linked to hepatocellular carcinoma, a type of liver cancer.

The International Agency for Research on Cancer categorizes aflatoxin B1 as a Group 1 carcinogen, meaning there is sufficient evidence that it causes cancer in humans.

The prospect of accumulating these mycotoxins in your body whenever you drink coffee is alarming. While more research is still needed, it’s wise to be cautious and try to limit your exposure.

Next, let’s explore how mycotoxins end up in coffee beans in the first place.

How Mycotoxins End Up In Your Coffee

Photo of coffee beans spread out on a table with visible mold growth.

Now that you know what mycotoxins are and their health implications, you may be wondering how these toxins get into coffee in the first place. 

There are a few key stages of coffee production where mycotoxin contamination can occur.

What Causes Mold And Mycotoxins To Develop In Coffee?

Mold growth and subsequent mycotoxin production can take place:

  • On the coffee plant itself, especially if growing conditions are warm, humid, and wet. Molds like Aspergillus can colonize developing coffee cherries.
  • During the harvest and processing of the coffee beans. If beans are not dried thoroughly or quickly enough, it creates an environment prime for mold.
  • In storage and transportation of green or roasted coffee beans. Improper storage leading to moisture buildup, encourages mold growth.

The coffee plant, drying method, and storage conditions play a huge role in potential mycotoxin levels. 

But here’s the tricky part – there’s no straightforward cutoff for how much is too much.

Understanding Mycotoxin Standards And Varying Levels

When it comes to guidelines and regulations for mycotoxins, there is no clear consensus worldwide or even at the federal level in the United States.

This leaves consumers trying to parse what amount of mycotoxin exposure is considered “safe”.

In the U.S., the FDA has set “advisory levels” for certain mycotoxins, but these are meant only as recommendations, not legal limits. There are currently no enforced federal standards for mycotoxins in coffee or most other agricultural products.

The European Union often leads in establishing regulatory limits for food contaminants. For coffee, the EU has set maximum levels of 5 parts per billion (ppb) for ochratoxin A and 10 ppb for aflatoxin B1.

Many other countries look to follow the EU’s lead on food safety benchmarks.

However, real-world mycotoxin amounts can still vary significantly, even among regulated coffees. One recent study analyzed 89 commercial coffee products in Italy for ochratoxin A. The levels ranged wildly from <0.5 ppb to 22 ppb, with over 10% exceeding EU limits.

So while these limits provide some governmental guidance, mycotoxin levels depend on many factors related to coffee production and storage. Defining an exact “safe” threshold is also challenging due to limited and conflicting data on the long-term impacts of exposure.

For now, minimizing regular intake seems a prudent approach.

Photo of a laboratory setup with petri dishes containing coffee samples.

As a consumer on the hunt for mold free coffee, look for coffee brands that voluntarily meet or exceed EU standards. 

Supporting companies that go above and beyond to limit mycotoxin contamination will incentivize the industry to continue improving food safety.

Tips To Reduce Your Risk Of Moldy Coffee

  • Choose reputable coffee brands that thoroughly check for mold issues.
  • Choose arabica beans rather than robusta and opt for dry-processed coffee when possible. These tend to have lower contamination rates.
  • Properly store coffee beans to prevent moisture and mold growth.
  • Consider certified mycotoxin free coffee to reduce exposure from your daily cup.

Being an informed consumer and also following proper coffee storage best practices can go a long way in limiting health risks!

Expert Insights On Mycotoxins In Coffee Beans

To get an informed perspective on mycotoxins in coffee, I spoke with Dr. Brietta Oaks, a Professor at the Department of Nutrition at the University of Rhode Island. Brietta shares insights from actively researching detection methods and mitigation strategies for coffee mycotoxins.

“There are still open questions surrounding safe limits and how processing affects mycotoxin levels that require further study,” she explains. “But what we do know is that proper drying, roasting, and storage methods make a big difference.”

Dr. Oaks recommends buying from established coffee brands that conduct batch testing. “Reputable companies monitor for mold and mycotoxin contamination throughout production, which provides quality assurance to consumers,” she says. Her lab is also experimenting with vacuum sealing to limit post-roast mycotoxin development.

While moderate intake is considered safe for healthy adults, she advises those with liver conditions or compromised immunity to be especially cautious.

By avoiding heavily contaminated beans through vigilant sourcing, however, coffee can be part of a healthy diet.

The Bottom Line on Mycotoxins in Coffee

When it comes to coffee and mycotoxins, moderation and smart choices are key. 

By selecting reputable coffee brands that thoroughly check for mold, choosing processing methods like dry and arabica beans that limit contamination, and avoiding improper storage that encourages mycotoxin growth, you can reap the antioxidants and other benefits of coffee while reducing the potential health risks.

Also, remember, aside from toxins, drinking coffee in moderation, sticking to 1-2 cups per day, is also recommended. While research on safe levels is ongoing, small amounts of mycotoxin exposure from coffee are unlikely to cause harm in healthy adults. 

So go grab your coffee maker from the trash, dust it off, grind your favorite coffee bean, and brew some great-tasting coffee. You needn’t worry. 


Additional Resources on Mycotoxins in Coffee

If you want to know more about potential mold in coffee, Here is some additional reading on mycotoxins in coffee from reputable sources.
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