Tea without Aspergillus flavus or parasiticus?

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Tea without Aspergillus flavus or parasiticus?

Postby Asper » Jun 19th, '11, 10:15

Hi all,

You may know, Aspergillus mold is used to ferment some teas. Most teas have some amount of it.

The question is, what teas have a risk of having the bad kinds of Aspergillus i.e. flavus or parasiticus? These produce aflatoxin, which causes cancer.

Can anyone here clarify this issue?


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Re: Tea without Aspergillus flavus or parasiticus?

Postby wyardley » Jun 19th, '11, 23:37

What do you mean by "fermented"? Fermentation and oxidation are often confused in reference to tea. Most teas that you will see people discussing here are oxidized by actually physically bruising the leaves, or possibly in some cases via a chemical process, and most of them are not fermented in the sense you're talking about.

I had never heard of Aspergillus mold until your post, but perhaps this (from a quick web search) will clear some things up:

http://aspergillusblog.blogspot.com/200 ... e-tea.html

So I think you may be wrong that "most tea" contains this kind of mold.

It appears as if this may be one of the molds involved in the fermentation of pu'er (at least ripe pu'er), and perhaps in some other kinds of Chinese black / dark tea (hei cha). This is different from the type of black tea (what the Chinese call hong cha / red tea) that this sub-forum is for. That kind of black tea is fully oxidized, but not fermented.

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Re: Tea without Aspergillus flavus or parasiticus?

Postby Drax » Jun 20th, '11, 06:59

Great article, thanks, wyardley!

Wikipedia covers the topic of pathogens briefly at this link. I think it's important to point out that a few species of Aspergillus cause problems, while the genus contains "several hundred" species.

So which teas contain the bad ones? I think it's just like every other food product -- sometimes bad stuff happens. Case in point: bean sprouts in parts of Europe...

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Re: Tea without Aspergillus flavus or parasiticus?

Postby debunix » Jun 20th, '11, 10:54

My best attempt at a pubMed search last night for 'aflatoxin' and (tea or puerh) yielded a couple of dozen articles about teas (black, green, but no mention of oolong or puerh) as antioxidants, with their tannins and other compounds protective against aflatoxin-induced damage.

Seems like the relevant literature is not in English.

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Re: Tea without Aspergillus flavus or parasiticus?

Postby Bakkoi » Jun 29th, '11, 23:27

I'm just getting into brewing Chinese tea, and unlike Japanese tea, it seems that there is a 'washing' step, where the tea gets its first infusion for about 7-10 seconds and this is discarded. One boiling rinse would probably rinse away most of the mold spores.

Maybe this is the reason why this part of the ritual exists. Ancient Chinese secret?

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Re: Tea without Aspergillus flavus or parasiticus?

Postby AlexZorach » Sep 27th, '11, 17:32

I've never heard of this issue with tea, and I've researched tea a lot. Did you read this association somewhere in a reputable source? If you did not, I would just dismiss it. But if you read it in a reliable source, please by all means share it here because I'd be curious to read about it.

There are some (generally very rare) issues with the safety of tea, but they're mainly from contamination due to pesticides or other chemicals, which is usually not an issue if you know the source of your tea and buy high-quality tea from a reputable company. There have been some mold / bacteria issues too associated with the wet-piling process used to make shu Pu-erh. And then...the only other safety issue with mold and bacteria that I've read about has been with the making of kombucha.

If you want to worry about the safety of your food supply, how about starting with all the really nasty food additives that are (legally) added to food in the U.S.? BHA, BHT, artificial sweeteners, food colorings, trans-fats (hydrogenated fats), meat and dairy from GMO-corn-fed cows factory-farmed with lots of drugs, the list goes on...if you live in the U.S., you're probably consuming a lot of these things and they're probably going to harm your health far more than anything in a cup of tea is!

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Re: Tea without Aspergillus flavus or parasiticus?

Postby ploutos7 » Sep 27th, '11, 23:59


This article states the bacteria found in puerh.


This states that no toxicity was found in puerh when tested on mice.

For black tea I'm not sure if these bacteria are present, yet all the articles on puerh and green tea state that there's no issue with aflatoxin.

Google scholar is a good place to start when looking for quantifiable research such as this. If you actually search tea and aflatoxin (http://scholar.google.com/scholar?hl=en&q=tea+aflatoxin&btnG=Search&as_sdt=0%2C31&as_ylo=&as_vis=0) the first few articles actually link tea polyphenols as being protective against the carcinogenic effects of aflatoxin.

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