Tea (rec.drink.tea) Discussion relating to tea, the world's second most consumed beverage (after water), made by infusing or boiling the leaves of the tea plant (C. sinensis or close relatives) in water.

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Old 23-09-2007, 04:21 PM posted to rec.food.drink.tea
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Default worried about pesticides in tea?

It was a merchant, a local of XiPing (one of the big producers of TGY
besides GanDe) that told me to stop drinking his tea and Wulong from
Fujian.


Yeah, stop drinking his tea and any tea from Fujian. Let all the
Fujian people buy the tea. There are so many people in Fujian with
money - and they all drink tea; if one consumer stops buying - no one
cares. The demand is so darn huge in Mainland China anyway.

I think that's the problem right there. Chinese tea producers won't
change much until the mass of Chinese consumers themselves start
demanding pesticide-residue free tea.


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Old 23-09-2007, 04:46 PM posted to rec.food.drink.tea
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You can see Taiwan from Xiamen? Really? I've spent some time in
Xiamen, and I could see Jinmen, which is administered by Taiwan and
produces really good cutlery but no tea.


Yeah, but technically, that is still Taiwan, isn't it?

The closest point to Taiwan, which I believe is the Gaoshan area near
Fuzhou, is about 80 miles.


Well, Lianjiang county is a county near Fuzhou that is partly
controlled by Mainland China, and partly controlled by the ROC. The
outlying islands anyway, are controlled by the ROC, and that's a tea
producing area. In that area, they all speak Fuzhou dialect. It's only
about 19 Km to the mainland.

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Old 23-09-2007, 06:20 PM posted to rec.food.drink.tea
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Yeah, stop drinking his tea and any tea from Fujian. Let all the
Fujian people buy the tea. There are so many people in Fujian with
money - and they all drink tea; if one consumer stops buying - no one
cares. The demand is so darn huge in Mainland China anyway.


Already done. Also, most people from here don't drink tea from Fujian
anymore either. Most of their big revenue comes from illegal
smuggling anyway; giving a few million people health problems because
of their filthy tea is the least of their worries. Sad to say.

I think that's the problem right there. Chinese tea producers won't
change much until the mass of Chinese consumers themselves start
demanding pesticide-residue free tea.


Won't happen. Most Chinese are relatively ignorant that this is even
a problem and the Chinese media is making sure that it doesn't look
too serious. They are out to make SARS look like the common cold.

Damn, I hate being so negative. What's wrong with me?


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Old 23-09-2007, 06:25 PM posted to rec.food.drink.tea
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There's another point I should mention. Many Taiwanese businesspeople
come to Fujian and invest in Fujian. So they might set up tea farms
and grow Taiwan tea - right in Fujian. The same for Fujian tea farmers
and entrepreneurs - they will find some suitable and cheap land, and
start tea cultivation. So the so-called Taiwan tea you drink may not
even be from Taiwan.



Also an excellent point. It's why I only buy from sources IN TAIWAN
from Taiwanese people that are into the tea trade. Mainland "GaoShan"
tea is just as filthy as TieGuanYin and you can taste it.

I wish I could invite ya'll down to my house in Dongguan to have a
blind tasting: some top grade TGY vs. some supermarket grade GaoShan
Tea from Taiwan. Your jaws would drop.


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Old 23-09-2007, 08:18 PM posted to rec.food.drink.tea
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Phyll wrote:
I am curious to
find out if DDT or other banned substance is in older teas, which
command high prices for being collectible.


Good news is that DDT and many other controlled pesticides aren't
actually particularly bad for people in applied amounts. (I'm not sure
that there is even a single example of someone dying from ingesting
grams of the stuff, which happened not infrequently.) DDT was banned
because - being fat-soluble and metabolized only very slowly - it
concentrates up the food chain. So top-predator birds had problems with
egg shell development. We'd have to eat the cats that fed on the mice
that ate the beetles that ate the Pu-erh weevils...

I'm not a medic or biologist, but my impression is that many of the
really nasty pesticides like cholinesterase inhibitors have high acute
toxicity (e.g. to field workers) but very little chronic risk in lower
doses. Kind of the opposite of heavy-metal poisoning, like recent lead
problems. FWIW, I don't worry about it, and I do think a lot about food
safety.

-DM


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Old 23-09-2007, 08:52 PM posted to rec.food.drink.tea
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there. Near Fuzhou, there is a town called Fuding, where they produce
white tea. Fuzhou has a lot of good eats there. Really delicious
stuff. Xiamen has some good food too. Lots of seafood - but probably
all polluted. Anyway, it tastes good.


Niisonge, I am glad you find something nice to say about Fuzhou. My
paternel grandparents and distant relatives are from that region. I
have never visited the city itself, as where were from more distant
Fuzhou villages.

Since you mention food, could you please tell me what you find nice
about it? My grandmother was a good cook, but ever since she passed
away, I solely missed Fuzhou cooking. As a boy, she never bothered
trained me in the art of cookery.


The food there is not so great either. But Tieguanyin is also grown in
the smaller towns in the mountains around there. So it would probably
be cleaner than the stuff that they grow nearest the town.


Agree.

I think in fairness to Anxi, you really have to be talking about the
mountainous villages of Xiping, Xianghe and Gande, where the authentic
Tieguanyin are grown.

Could you share with us your opinions on how clean and dirty these
villages are?

I will be very keen to have their teas tested to remove any doubts.

Julian
http://www.amazing-green-tea.com

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Old 23-09-2007, 09:01 PM posted to rec.food.drink.tea
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Good news is that DDT and many other controlled pesticides aren't
actually particularly bad for people in applied amounts. (I'm not sure
that there is even a single example of someone dying from ingesting
grams of the stuff, which happened not infrequently.) DDT was banned
because - being fat-soluble and metabolized only very slowly - it
concentrates up the food chain. So top-predator birds had problems with
egg shell development. We'd have to eat the cats that fed on the mice
that ate the beetles that ate the Pu-erh weevils...

I'm not a medic or biologist, but my impression is that many of the
really nasty pesticides like cholinesterase inhibitors have high acute
toxicity (e.g. to field workers) but very little chronic risk in lower
doses. Kind of the opposite of heavy-metal poisoning, like recent lead
problems. FWIW, I don't worry about it, and I do think a lot about food
safety.

-DM


Dogma/Mynight

I am with Dogma with this one. I think environmental pollution (road
traffic, air, water, lead, fluoride etc) are a more serious threat
than pesticides itself.

Tea garden situated in high attitude sloping land tend to use little
pesticide anyway. Usually these best parts of tea garden are used to
make the really high grades, like the better tasting Tieguanyin
Wangs.The price is usually a reflection of the location of the same
tea garden.

Just my opinion. I want to test their teas to be sure, anyway.

Julian
http://www.amazing-green-tea.com

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Old 23-09-2007, 09:13 PM posted to rec.food.drink.tea
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Nigel/Ankit

This discussion is getting better and better! I am really excited!

I have been ill the entire weekend, but I just can't help
participating.

Let's retain a sense of balance here - fluoride is naturally

present
in tea and is not a contaminant (neither is it a heavy metal).


Nigel, thanks for the correction.

I am particularly concerned about fluoride (and aluminium) because of
the focus on past scientific studies, mainly in West China, where
people had too much of them from the consumption of compressed tea.

Also the recent case study of a women in US suffering from fluorosis.

I am not an expert, but there have also been concern about fluoride
pesticide (if there is such thing, please correct me if I am wrong).

Again, open to correction. I really need to educate myself in this
matter much further.

My question is which tea do you test?

Dried tea leaf chemical composition?
Brewed tea liquor chemical composition?

I believe dried tea leaves contain less than half of soluble solids?

I have also thought that harmful substances in dried tea leaves are
less likely to be soluble.

So brewed tea liquor is better, but much more subjective as
preparation method can influence chemical composition.

So I guess standard practice is dried tea leaves, but bearing in mind
we are testing for a maximum here, and this is just an INDICATION
(probably less) of the amount present in brewed tea liquor?

Any data on the water-solubility of these pollutants will definitely
be very relevant.

Probably less soluble than vitamin C, theanine, caffeine and
catechins?

Julian
http://www.amazing-green-tea.com

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Old 23-09-2007, 09:23 PM posted to rec.food.drink.tea
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DogMa wrote:
Good news is that DDT and many other controlled pesticides aren't
actually particularly bad for people in applied amounts. (I'm not sure
that there is even a single example of someone dying from ingesting
grams of the stuff, which happened not infrequently.) DDT was banned
because - being fat-soluble and metabolized only very slowly - it
concentrates up the food chain. So top-predator birds had problems with
egg shell development. We'd have to eat the cats that fed on the mice
that ate the beetles that ate the Pu-erh weevils...


Precisely. I grew up with sprinking DDT between the sheets before
getting into bed, and pouring DDT-laced diesel into the fire before
cooking outside to keep the bugs away. Not that it isn't an environmental
disaster, but it's not a human health disaster. Also, sad to say, it's
not as effective as it was when I was a kid because insects have evolved to
develop tolerances. Bug generations are very short.

That said, if you want to do testing for DDT, there is an easy titration
test that has a high false positive rate, a harder titration test that
has a lower false positive rate, and a chromatographic test that requires
much less material and is much easier if you have the machine. I assume
any professional laboratory today is using the chromatographic method,
but if you want to do it at home you can get the reagents to do the older
tests.

I'm not a medic or biologist, but my impression is that many of the
really nasty pesticides like cholinesterase inhibitors have high acute
toxicity (e.g. to field workers) but very little chronic risk in lower
doses. Kind of the opposite of heavy-metal poisoning, like recent lead
problems. FWIW, I don't worry about it, and I do think a lot about food
safety.


Yes, but don't forget there are some organometallic pesticides in common
use today now, which are indeed the opposite. On the gripping hand, we
also have to contend with the fact that the pesticides used in the field
are not exactly reagent-grade and come with all kinds of other contaminants
in possibly significant amounts.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Old 24-09-2007, 07:24 AM posted to rec.food.drink.tea
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Dried tea leaf chemical composition?
Brewed tea liquor chemical composition?


both are tested by the lab..






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Old 24-09-2007, 01:34 PM posted to rec.food.drink.tea
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Scott/Dogma

any professional laboratory today is using the chromatographic method,
but if you want to do it at home you can get the reagents to do the older
tests.


Can you explain what chromatographic is about is layman's terms? How
is that different from gas-chromatography which I came across in more
recent studies?

doses. Kind of the opposite of heavy-metal poisoning, like recent lead
problems. FWIW, I don't worry about it, and I do think a lot about food
safety.


Could you elaborate further on the "recent lead problems"? Is that the
toy paint thingy? That seems to be a different issue from
environmental pollution.

Yes, but don't forget there are some organometallic pesticides in common
use today now, which are indeed the opposite. On the gripping hand, we


Could you explain what is organometallic pesticides? Is there such
thing as fluoride pesticide? How can I read about the different kinds
of pesticides available, pros and cons etc?

also have to contend with the fact that the pesticides used in the field
are not exactly reagent-grade and come with all kinds of other contaminants
in possibly significant amounts.


What is reagent-grade in layman's terms?

Sorry for the bother. I don't really intend to take up too much of
your time. But if you can point me in the right direction, I will much
appreciate it.

Thank you.

Julian
http://www.amazing-green-tea.com

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Old 24-09-2007, 01:35 PM posted to rec.food.drink.tea
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On Sep 24, 7:24 am, Ankit Lochan wrote:
Dried tea leaf chemical composition?
Brewed tea liquor chemical composition?

both are tested by the lab..


Thank you.

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Old 24-09-2007, 03:45 PM posted to rec.food.drink.tea
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juliantai wrote:
Scott/Dogma

any professional laboratory today is using the chromatographic method,
but if you want to do it at home you can get the reagents to do the older
tests.


Can you explain what chromatographic is about is layman's terms? How
is that different from gas-chromatography which I came across in more
recent studies?


Okay, if you take a paper sheet and you put a drop of something in it,
and you put the bottom of the sheet in a solvent, the various constituents
of that drop will move up the paper by capillary actions, and lighter
molecules will move up more.

Today we have automated machines... you drop a liquid in, and the machine
spits out a graph of composition vs. molecular weight. Fancier systems
will also spit out level vs. valence vs. molecular weight by applying charge
to the sample as well and separating it that way. A semi-skilled technician
can do the testing and it only takes an analytic chemist to read the results,
which means you can do lots of tests fast.

Yes, but don't forget there are some organometallic pesticides in common
use today now, which are indeed the opposite. On the gripping hand, we


Could you explain what is organometallic pesticides? Is there such
thing as fluoride pesticide? How can I read about the different kinds
of pesticides available, pros and cons etc?


It's an organic molecule with a metal in it. I don't know where you would
get good information on available pesticides because they change so much,
but I'd start with a good college library.

I don't know of any pesticides containing fluorine but I'm no expert in
the subject. Fluorine for the most part is a lot more expensive than
chlorine which is often an effective subsitute. Pesticides are engineered
for low cost and low reactivity.

also have to contend with the fact that the pesticides used in the field
are not exactly reagent-grade and come with all kinds of other contaminants
in possibly significant amounts.


What is reagent-grade in layman's terms?


If you buy a bottle of 50% ethanol from a chemical supplier, it will
contain 50% alcohol and 50% water and very little else, and most of the
other items will be listed on the data sheet that comes with it. You can
order with all sorts of different purity requirements... if you need it to
have no detectable iron, you can order one grade, if you need it to have
no detectable chlorine, you can order another. "Chemically pure" reagent
grade is about the lowest laboratory grade you'll see but it's still very
pure compared with vodka over the counter.

A lot of "practical grade" chemicals are much lower than vodka grade,
because they're used in applications where they don't need to be very
pure. If you look at the assay on a fertilizer grade ammonium nitrate,
you'll see it's only about 95% ammonium nitrate and the rest is junk and
God only knows what. But for fertilizer, that's fine.

Sorry for the bother. I don't really intend to take up too much of
your time. But if you can point me in the right direction, I will much
appreciate it.


Call your local extension service and ask for a reference to a local
pesticide chemist.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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Old 25-09-2007, 01:04 PM posted to rec.food.drink.tea
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On Sep 24, 3:45 pm, (Scott Dorsey) wrote:

Call your local extension service and ask for a reference to a local
pesticide chemist.


Good advice but sadly Julian, who is located in the UK, will find it
hard to follow. We no longer have an Extension Service as would be
recognisable by US citizens nor even a Ministry of Agriculture - this
was replaced by DEFRA (Department for Environment, Food and Rural
Affairs) and the extension experts were disbanded long ago. Most of
the practical information quoted by DEFRA is culled from USDA sources!

However, to keep this on-topic aI searched the DEFRA site for "tea
growing" and the first hit is a DEFRA Newsletter mentioning
Tregothnan, the new commercial tea farm in Cornwall where weather is
very similar to that of Darjeeling. I have tasted this tea and was
surprized to find it very similar in taste. The article continues
that it's possible that climate change could extend tea growing to
other areas, particularly with springtime frost growing less common in
southern England - and since its publication I have seen reference to
Taylors of Harrogate planting tea in Yorkshire.

Nigel at Teacraft

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Old 26-09-2007, 08:20 PM posted to rec.food.drink.tea
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Scott et all

Thanks for your reply. I really appreciate it.

=============
Further Questions
=============

Yes, but don't forget there are some organometallic pesticides in common
use today now, which are indeed the opposite. On the gripping hand, we


Just out of curiosity, why is organometallic pesticides harm the
drinkers and not the workers?

It is interesting you compare pesticides to vodha, or spirit. Does
that tell me anything about the hot water solubility of this
pesticide?

====
PSD
====

I have found this article in the UK Pesticide Safety Directorate (PSD)

http://www.pesticides.gov.uk/food_industry.asp?id=546

As you can see, EU currently have MAXIMUM ALLOWABLE LIMITS for 30
pesticides residuals, with another 40 under discussion.

Not to mention other environmental pollutants.

It kind of struck me that low cost testing doesn't really exist, at
least for now, and the only logical place for comprehensive testing is
in the larger tea gardens, where it is subject to manipulation.

(

==================
My tentative conclusion
==================

The more I look into this issue, the less I am convinced pollution and
pesticides are an issue, especially if you are drinking a high grade.

First, a lot of tea quality is in the taste, so anyone can do their
DIY testing.

Second, as pointed to me earlier by Chagonwala, we drink only a few
grams of tea leaves each day. Only less than half is soluble in water.

Now compared this to the other foods you eat. Another 300 grams or
more? Do your vegetables and fruits and meats grow in high mountain?
Are they TRULY organic? They don't dissolve in water, do they? Have
they any history of health scare? Do they kill bacteria and virus and
reduce cancer risk?

Julian
http://www.amazing-green-tea.com



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