"Pu'er tea causes cancer" rumored again, does fermentation have aflatoxin?
Issuing time:2019-09-07 10:46
Jinxi Biological Network News: Recently, the well-known magazine "Science World", which is supervised by the Chinese Academy of Sciences and cooperated with the international authoritative science publication Newton, suddenly published "Can tea drink prevent cancer or cause cancer?" 》 The article once again made the question of whether Pu'er tea is carcinogenic a hot topic in the circle of friends. In fact, this is not the first time that rumors about Pu'er tea cause cancer, so what is the truth? Will things reverse? How do you view this problem in and outside the industry? Nandu reporters interviewed relevant scholars and industry professionals for this purpose.
"Carcinogenic" said to list multiple evidences
"Can drinking tea prevent cancer or cause cancer?" The reason why the article believes that Pu'er tea is carcinogenic is as follows. First, in 2010, researchers from the Guangzhou Center for Disease Control and Prevention randomly checked 70 samples of Pu'er tea on the Guangzhou market and found that all of them could detect aflatoxin, including The content of 8 servings of aflatoxin exceeded the limit of aflatoxin (5 μg / kg) prescribed by the Chinese Grain Standard. At the same time, it was also found that all Pu'er tea samples contained fumonisin and vomitin, and the content of 63 vomitin exceeded the standard limit (1 mg / kg). In addition, in 2012, a graduate student in food engineering of Nanchang University repeated the research of Guangzhou CDC, and the results were also consistent with the results of the Guangzhou CDC. 60 Pu'er teas were collected from the Nanchang market, all of which could detect Aspergillus flavus 7 of which exceeded the standard. Fumonisin and vomiting toxin were also detected, of which 41 vomiting toxins exceeded the standard.
In addition, the above article also cited a case from the Department of Nephrology of Maanshan Central Hospital in Anhui Province in 2012 to prove that the aflatoxin and other mycotoxins contained in Puer tea can cause harm to the human body. According to the article published in "Science World", a patient drank 10 grams of Pu'er tea every day, and after more than a month, aflatoxin poisoning caused acute liver damage.
The industry is meeting to study
Regarding the above-mentioned opinions, Zhang Liming, Secretary-General of Guangdong Tea Industry Association and Secretary-General of Guangdong Tea Association, admitted in an interview with Nandu reporters yesterday that the above article is not rigorous and it is tantamount to killing a stick for Pu'er tea .
According to its introduction, moldy Pu'er tea can often be drunk as soon as it is drunk. The normal storage of good Pu'er tea should not produce aflatoxin. Some of them that are detected to contain aflatoxin are often due to poor storage. This is consistent with the fact that rice is also stored when it is wet.
"In fact, the spot-checking of the Guangzhou Center for Disease Control and Prevention cited in the article is not a very powerful statement. First of all, aflatoxin was found in 8 of the 70 samples, and the proportion was not high, not to mention that the target of this spot-check was Puer tea stored in a wet warehouse with extremely low prices and extremely poor quality. For this article, we are in contact with Yunnan. The local agricultural department and tea organizations are already in discussion to discuss and do not rule out the possibility of legal rights protection. "Zhang Liming further Say.
As the largest Pu'er tea company in China, related personnel of Dongguan Dayi Tea Technology Co., Ltd., a subsidiary of Dayi Group, told reporters that it has not heard of the "carcinogenic" article. Good Pu'er tea is unlikely to cause cancer.
Expert: At present, there is no clear evidence of cancer caused by drinking Pu'er tea
Chen Wenpin, a tea research expert from South China Agricultural University, said in an interview with a Nandu reporter yesterday that Pu'er tea, as a traditional food in China, has a long history of safe consumption, and there is no relevant epidemic virus investigation and edible poisoning case report. In a sense, it is safe to consume the regular leading products of Pu'er tea.
Chen Wenpin believes that this article questioning Pu'er tea is a good starting point from the perspective of caring about Pu'er tea's safety. But when you read it carefully, you find that it is completely a biased lay article, and the content organization and writing are subjective speculations. Judging from a large number of current research and analysis, tea is a safe and healthy beverage that has been verified for thousands of years. Pu'er tea has anti-cancer functions like other teas, and there is no clear evidence that drinking Pu'er tea causes cancer.
In his view, regarding food safety, everyone should establish a scientific concept of safety risk awareness and toxicology dose-effect relationship, and understand the scientific concept of safety risk assessment and control.
According to public information, as early as 2005, Chen Wenpin published the article "Puer tea genotoxicity safety evaluation study" in "Tea Science". According to the article, "After the six tea samples tested were treated by gavage, the small The incidence of bone marrow micronucleus in mice was slightly lower than that in the blank control, suggesting that the tea samples tested all have a certain function of reducing the natural incidence of micronuclei, that is, the Pu'er tea samples tested have certain anti-mutation and anti-cancer effects. A large number of research reports have shown that tea and its polyphenols and catechins have anti-chromosome damage, anti-mutation and anti-cancer functions.
Why does Puer tea have aflatoxin?
It is understood that in the era of market chaos, in order to accelerate the fermentation of Pu'er tea, some profiteers placed the tea in a place with high humidity and high temperature to accelerate the transformation. It was aflatoxin.
Therefore, yesterday the Guangdong Tea Industry Association in the third-party research materials sent to Nandu reporters also reminded consumers to pay attention when buying Pu'er tea. Many teas are prone to mold in long-term storage in relatively humid places in southern Yunnan. Pollution. This kind of tea will have a so-called "kura taste". Another situation is that the tea that has been contaminated with mold has been stored in a dry and ventilated environment for a long time. The "cangwei" has basically disappeared, but the tea soup brewed has a slight tingling tongue. These teas are absolutely unnecessary.
Does fermentation always produce aflatoxin?
Nandu reporters have noticed that whether Pu'er tea will produce aflatoxin during fermentation is becoming a focus of debate in all parties.
"" Is the same as the biochemical mechanism of rotten peanuts producing aflatoxin. "One person reposted" Can tea prevent cancer or cause cancer? " "A doctor from a hospital in Guangzhou analyzed Nandu reporters.
The Guangdong Tea Industry Association issued a report to Nandu reporter yesterday that the fermentation is dependent on mold, but mold does not necessarily have aflatoxin.
The material shows that the fermentation process of Pu'er tea is a biochemical process involving mainly molds, yeasts, bacteria and actinomycetes. During the fermentation of Pu'er tea, four types of molds including Aspergillus, Rhizopus, Penicillium and Trichoderma were found. Among them, Aspergillus is the dominant microorganism in Pu'er tea fermentation process, as reported by Aspergillus niger. During the fermentation of Pu'er tea, aspergillus flavus and parasitic aspergillus should not normally appear. Not only should they not be propagated during the fermentation of Pu'er tea, but their presence will be inhibited by the predominant flora during fermentation.
In addition, Nandu reporters noticed that in order to publicize the safety of Pu'er tea to the outside world, the relevant person in charge of the Yunnan Provincial Department of Agriculture publicly claimed that Pu'er tea was a safe drink in July this year. The person in charge also quoted academician Chen Zongmao's introduction: "There have been many scientific tests that Pu'er tea can produce beneficial microorganisms such as Aspergillus niger and Penicillium, which can effectively inhibit the growth of harmful microorganisms and aflatoxin. The rumor that Pu'er tea produces aflatoxin and harmful microorganisms is untrue and is a statement without scientific basis. "
This article refers to http://foodmate.net/