Are fungal toxins a significant problem in coffee, and if so, can they be avoided?

Question

I stumbled across this blogpost which claims that coffee is awesome for our bodies but only if it doesn't have mycotoxins (toxins generated by fungi).

To quote them:

One study showed that 91.7% of green coffee beans were contaminated with mold. This is before they were processed, which allows even more mold to grow. Another study showed 52% of green coffee beans and almost 50 percent of brewed coffees are moldy. Coffee is easily one of the largest sources of mycotoxins in the food supply.

They conveniently sell coffee beans that underwent a different process and don't have mycotoxins, so I have to wonder if this is a real problem and if there are ways to avoid it besides buying from them.

Perhaps buying green beans and processing them somehow so the fungi are washed away?

Answer 1

Time to apply a bit of healthy skepticism here:

The blog post:

• Is (so far) the first and only one I've ever seen stating mold to be a practical problem in coffee - in the sense of being present in a high enough quantity to matter (mold grows everywhere).
• Uses all kinds of weasel words to describe symptoms ("edgy", "cranky", "useless mentally").
• Describes symptoms that are well in line with plain old caffeine withdrawal.
• Frequently links to other blog posts on the same site, most of which are "top 10 ways" and "top 5 reasons" fluff pieces.
• Manages to cite and thoroughly misuse two studies: one from 1995, and another from 2003. Both are about Ochratoxin A (OA), which isn't even the biggest risk; Aflatoxin is. (More on these later).
• Advertises a fairly expensive product, sold by the same author.

The author:

• Is, according to his LinkedIn profile (which I refuse to link here), the VP of Cloud Security at Trend Micro - a Silicon Valley tech company. I could not find any evidence that he or his his employer has any experience in human biology or nutrition.
• Makes all sorts of unusual claims about himself: "He upgraded his brain by >20 IQ points, lowered his biological age, and lost 100 lbs without using calories or exercise."
• Has an entire page of testimonials, which he frequently cites as "evidence".
• Has an entire site dedicated to product-peddling, including the ubiquitous six-second abs (yes, that's hyperbole) and a $60 "earthing mat".
• Has the following disclaimers on the product site (all in tiny print at the bottom):

  _{The statements made on this website have not been evaluated by the FDA (U.S. Food & Drug Administration). Our products are not intended to diagnose, treat, cure, or prevent any disease.}

  _{The information provided by this website or this company is not a substitute for a face-to-face consultation with your physician, and should not be construed as individual medical advice. The testimonials on this website are individual cases and do not guarantee that you will get the same results.}

• In short, he employs tactics which are commonplace among con artists selling magnetic bracelets. In my opinion, all his claims are technobabble, and I think they are not trustworthy.

The facts and studies:

• The largest sample tested was just 60 samples of beans, and was tested from only one source (Brazil). This is fine for individual studies, but in the real world there are hundreds (thousands?) of sources from many different countries. It's safe to say that the current studies don't even come close to testing all of the coffee from around the world.
• Both OA studies found an incidence rate of approximately 50% for the OA-producing mold, at wildly different concentrations (minimum 0.2 ppb in one study, maximum 7.8 ppb in another). If this tells me anything at all, it's that you should probably vary your source if you want to minimize your risk.
• Neither the FDA nor the EFSA actually have a legal limit for OA, but the EFSA "suggests" a limit of 8 µg/kg, which means that even the worst samples are below the very conservative legal limit.
• One study actually tested the incidence of OA in brewed coffee, not just the beans, and found a maximum of 7.8 ppb in the brew (that's 7.8 µg per 1 kg of ground coffee).
  • For reference, there's an EFSA directive recommending an intake of no more than 120 ng/kg (body weight) per week, which comes out to 8.4 µg/week for a 150 lb/70 kg individual, or 1.2 µg/day.
  • Based on the worst contamination of brewed coffee (7.8 µg/kg), doing the math, you'd have to consume the brew from 150 g of ground coffee per day. That's about half a standard-sized tin of coffee. Per day. If you drink that much coffee, shame on you.
• The 3rd study (the one rumtscho linked to, not cited by the blogger/con artist) looked at Aflatoxin, not Ochratoxin, which actually is regulated by the FDA at a maximum of 20 ppb. This study also showed approximately a 50% incidence rate after roasting, with the highest concentration of AT being 16 µg/kg for decaf (less with caffeine). So that means with any random cup of coffee you have up to a 50% chance of consuming an amount of AT that's still well below the FDA limit - that's very nearly zero risk.
• None of the studies test the rate of mold growth on beans while in storage under various conditions (temperature, humidity, etc.), so we can't comment on what happens in storage. So I guess if you want to really be on the safe side, only buy as much coffee as you think you can use in a week or two.

Conclusion:

Don't believe everything that people tell you - especially people with something to sell. Unless you're drinking gallons of coffee a day, brewed coffee is perfectly safe.

Answer 2

The take away is not all coffee is created equal try different beans until you find one that gives you the best bang for your buck, Starbucks dark roast puts me in a better mood than foldgers or Maxwell house. Mycotoxin ? Branding? Subjectivity?

It's very possible that unnamed blogger / coffee and supplement salesman has a sensitivity to mycotoxins.That people who regularly consume healthy fungus and bacteria aren't normally affected by.

Or it could be that other chemical components of the coffee influenced by the growing region that are best suited to his physiology.

We don't know what the real reason is , we can assume much of the coffee available to us is perfectly safe , with the exception of all that toxic caffeine stuff sometimes called a phytotoxin!!!

Answer 3

I looked at the contention that fermentation is to blame for mycotoxins in coffee, and also digged up a number of brands that fit the criteria for low-mycotoxin coffee beans here: blog.healclick.com/mycotoxin-free-coffee-brands/

Personally I love bulletproof coffee both for flavor & for performance, but I haven't been able to stomach paying $25 for 1 lb of coffee.

Answer 4

My university has access to the study @w00t linked in a comment here, so I thought I'll provide a summary of their findings.

1. Do green coffee beans contain aflatoxins? They found that yes, coffee beans naturally grow molds which produce aflatoxins. Molds and toxins were isolated from 17 out of 30 samples of green coffee beans they purchased from local markets.

2. Do roasted coffee beans contain aflatoxins? Yes, 22 out of 30 samples had molds and aflatoxins. The levels were lower than in green beans (about 30% less).

3. Does roasting reduce aflatoxins? They tried three types of roasting (oven, microwave and traditional). All methods roughly halved the aflatoxins, with traditional roasting resulting in the highest reduction (55.9%). The difference between methods was very small, ranging from ~45% to ~55%.

4. Does caffeine affect aflatoxin growth? They put caffeine and aflatoxin-producing molds in a mixture of sugar, yeast, and water, and waited. The molds grew with only half the speed of molds in the same mixture without caffeine added. They couldn't detect any aflatoxins in the mixture itself, but say this could be because they started with small amounts of mold. (Their measurement method is sensitive enough to detect tenths of micrograms per liter).

Conclusion: You can't get rid of mold and their byproducts (aflatoxins) in your coffee, but you can reduce them somewhat. If you insist on that, use freshly roasted coffee, no decaf. Be aware that the study doesn't give an answer if brewing coffee with moldy beans results in aflatoxins in your coffee. So you can't use it to arrive at a recommendation for safe coffee-drinking habits. Change them if you want to, but be aware that it will be a speculation. The question whether the alpha toxins are dangerous to human health, or which concentrations can be considered absolutely safe, is not researched in this study. Also, they found that while changing the roasting method does have an effect on the mold present in the beans, the difference was very small - so even if it has negative effects, I doubt that you can avoid them by changing the roasting method.

Answer 5

I'm the guy who made this coffee. In my opinion, yes, alfatoxins are dangerous for you, and you should drink coffee which doesn't have them. Most coffee gives me awful symptoms, ones so bad I quit coffee for 5 years before I figured it out. Now I only drink this coffee, because it gives me no symptoms, and I am selling it because I believe it is better for others too. My opinion is that

There are toxins (specifically biogenic amines and mycotoxins) present in coffee at levels high enough to affect how you feel.

Am I saying coffee will kill you? Nope. But bad coffee slows you down - a lot - and low toxin coffee speeds you up - a lot.

To back this opinion, I am currently conducting an IRB-approved study, with Stanford University's assistance, to test the mental performance of people on my Upgraded Coffee vs Starbuck's dark roast. I can also invite you to test the toxin-free coffee for yourself, by purchasing it from me or from other sources (I wrote a blog post "How to find high performance coffee in your city", google it).

My other sources for my opinion are

• This study. It shows detectable aflatoxin in 85 of 127 samples. Some (many) were below the legal limit, but the problem is that the legal limit is not the safe limit, it's the economically feasible one.
• This conference talk. It says that coffee can contribute up to 25% of your daily "safe" (not by my standards) dose of the OTA toxin.
• If you google "coffee mycotoxin" you can find many other studies which have shown the presence of mycotoxin in coffee.

Aaronut's answer suggests that I am not qualified to judge whether coffee with alfatoxins is dangerous. I feel that his "The author section" is an example of "attacking the messenger", which is a poor tactic. Here are my credentials:

• I'm a very successful Silicon Valley exec with enough money that I don't need to con people at all.
• I run an anti-aging group that brings world-class experts in every month.
• My wife is an MD and co-author of my book on nutrition for pregnant women (currently in publishing)
• I've lectured internationally on human performance
• 100 000 people a month read my blog

Answer 6

I know about nuts, they can grow fungus that generates Aflatoxin http://en.wikipedia.org/wiki/Aflatoxin which is knows to cause hepatocellular carcinoma.
There are strict regulations that requires Aflatoxin measurement in nuts in food industry in many parts of the world.

I don't know about coffee, though, but it should be similar.