China is a big food country, even there are many kinds of pickles, and all parts of the country will make pickles in their own way as a daily snack.
Usually we eat pickles, pickles, sauerkraut, kimchi, these are collectively called pickles. Famous are Northeast sauerkraut, Sichuan kimchi, Fuling squeezed vegetables, Yangzhou pickles, Xiaoshan dried radish... Don't say it, drool.
However, this traditional cuisine has also been questioned a lot.
Pickles have been reported to be harmful, and the World Health Organization has identified it as a possible carcinogen.
The WHO's global incidence of stomach cancer shows:
The number of stomach cancers in China accounts for nearly half of the world's stomach cancers, and the east Asian countries that love pickles have a high incidence of stomach cancer.
Are pickles really carcinogenic?
<h1 class="pgc-h-arrow-right" > pickles carcinogenic ? </h1>
One of the reasons why pickles have a carcinogenic risk is that they contain nitrites, which may be converted into carcinogenic nitrosamines in the body.
Nitrite is not uncommon in food, it is an important preservative in meat products.
But in pickles, it is produced in the natural production process:
Vegetables absorb nitrogen from soil and fertilizer during the planting process to form nitrates.
Nitrate is converted into harmful nitrite under the action of harmful microorganisms.
However, with the progress of pickling and fermentation, there are fewer harmful microorganisms and nitrite will be degraded.
If you make pickles at home, the trend in nitrite content is to first rise to the top and then decline.
Many cases of poisoning by eating pickles are pickles that eat pickles with nitrite content at their peak.
Even if it is not at the peak, if the nitrite is not reduced to a safe range, eating too much of this pickle will increase the risk of carcinogenicity.
The national standard requirements for the nitrite content in pickles are ≤ 20 mg/kg.
We see that many netizens will start eating after 1 to 2 weeks of pickling.
The question is, how long does it take for pickles to reduce the nitrite content to a safe range?
We did an experiment on pickles and the results were as follows:
<h1 class="pgc-h-arrow-right" > homemade pickle reviews</h1>
Since there are so many, very many pickles, everyone will feel that their home practices are the standard practices, so we have made pickles three times in two consecutive years.
Twice, I made a total of 12 jars of pickles at the company, including spicy kimchi with chili, ginger, garlic and other ingredients, and pickled sauerkraut with nothing but salt and vegetables.
In addition, she flew to the home of a fan in the northeast to collect sauerkraut made by her mother.
Since the kimchi method adds many ingredients and adds uncertainty, we first take the simplest, salt-only method to compare.
<h1 class="pgc-h-arrow-right" > nitrite</h1>
Pickles are sampled every 7 days and sent to the laboratory for testing on the same day.
The nitrite content of pickled greens reached 420 mg/kg on day 7, 21 times the safety line. By day 28, the nitrite had not fallen below the safety line.
At the same time, at 7 days and 14 days, there are many miscellaneous bacteria - coliforms.
Bacteria are the culprits in turning nitrates into nitrites.
The nitrite of pickled cabbage did not fall below the safety line on day 7, but it was only 2.9 mg/kg on day 14 and was ready to eat. There has been no weeds.
Pickled sauerkraut in the northeast is from day 7 onwards, and the nitrite is not high, so it is safe to eat for 7 days +.
< h1 class= "pgc-h-arrow-right" > lactic acid bacteria</h1>
From the above test results, we can find that the nitrite content of pickles made of green vegetables is significantly higher than that of pickles and sauerkraut made of Chinese cabbage, and the time to reach the safety line is longer. Why?
We measured the lactic acid bacteria content of these pickles:
The lactic acid bacteria content of pickled cabbage and northeast sauerkraut is significantly higher than that of pickled greens.
Lactic acid bacteria can increase acidity, inhibit the growth of harmful bacteria, and promote nitrite degradation during fermentation, greatly reducing the nitrite content.
<h1 class = "pgc-h-arrow-right" > the miraculous vitamin C</h1>
In the process of reviewing the information, we found a practical trick:
Vitamin C inhibits the production of nitrite and also promotes the degradation of nitrite that has already been formed.
At a ratio of 0.4 g/kg, we grind and dissolve the vitamin C tablets and add them to the jars where the vegetables are prepared.
(A small white bottle of vitamin C for 3 bucks is fine, and only 4 tablets need to be added to 1 kg of vegetables.) ）
Pickled greens with vitamin C added at the beginning not only reduced the nitrite content by nearly half at the peak, but also dropped below the safety line on day 21.
Pickles that do not have vitamin C added wait 35 days to be lowered below the safe line.
It can be seen that the pickles are added with vitamin C, which not only has a small risk of poisoning, but also can be enjoyed earlier.
In addition, we also tried to add vitamin C halfway and found that the nitrite of pickles was also greatly reduced.
If you've made a few cans at home, you can add some vitamin C to it.
pickle
We also measured kimchi with ginger, garlic, pepper, pear, apple and other ingredients, and the results were not much different from the above pickled cabbage.
< h1 class="pgc-h-arrow-right" > summary</h1>
After two years of pickling, I believe that when I see this, many people will say that our family's pickles are not doing this.
In fact, we have solicited pickles from everyone before, although they are different, but they are similar.
Judging from the results of our evaluation, the principle is not much different, and the conclusion can be used for reference:
Pickles made with greens take 35 days to reach the safety line range, and pickles made with Chinese cabbage can be eaten in 14 days;
Adding vitamin C can make nitrite decrease rapidly, whether it is added at the beginning or halfway;
The content of nitrite will also be affected by temperature and environmental health, if you do not grasp it well, it is recommended to buy packaged pickles in the supermarket (packaged with detailed production information).
Pickles are delicious, but it's best to avoid eating them when they're at their highest nitrite.
I believe that you must have friends and family members who love to eat pickles and love to make pickles, so forward this article to them and eat pickles together healthily.
In addition, there are many causes of stomach cancer, not just pickles, such as Helicobacter pylori, excessive intake of nitrite and so on.
Resources:
[1] http://gco.iarc.fr/today/
[2] Etemadi A, Safiri S, Sepanlou S G, et al. The global, regional, and national burden of stomach cancer in 195 countries,1990–2017: a systematic analysis for the Global Burden of Disease study 2017[J]. The Lancet Gastroenterology & Hepatology, 2020, 5(1): 42-54.
Pang Yuchen,Li Yuanzhi,Qiao Qian,Chen Pei. Study on methods for reducing nitrite in pickled vegetables[A]. Guangdong Food Society." Health and Safety" Symposium and Proceedings of the 2015 Annual Meeting of the Guangdong Food Society[C].Guangdong Food Society: Guangdong Food Society, 2015:3.
Li Shuhua,Pu Biao,Chen Fengzheng. Effects of VC and fermentation temperature on nitrite in bubble ginger[J].China Brewing,2006(02):34-36.
Fang Yuezhen,Lin Longwu. Nitrite poisoning caused by eating pickles together[J].Straits Journal of Preventive Medicine, 2004(06):34-35.