( Background: There are a few friends ask me: preserved foods are toxic吗? salted and pickled sugar What's the difference? pickles and pickles What's the difference? pickled vegetables and What is the difference between salted duck eggs? If harmful, why the country is still permitted to sell? detailed answer at this concentration of 。)
have heard a lot of friends, preserved food harmful, it should be as little as possible吃. Thus, sauerkraut, kimchi, pickles,酱豆腐,咸鸭蛋, preserved fruit, such as at fast food to make the list.
the first question that must be addressed are: pickled foods are harmful then what? In fact, it is nothing more than the harmful effects of both: first, some pickles too high nitrite, which things are not only toxic, but also possible in food and protein synthesis of amines carcinogenic substances stronger "nitrosourea amines "; second, salt or sugar is too high, the adverse chronic diseases. If you would also like to add a third charge, that is, vitamin loss, and nutritional value of low and toxic but is an entirely different concept.
second required that question is: What are the preserved foods containing nitrite do more? In fact, there is a major safety problem are pickled vegetables, pickled vegetables and are short-term, that is, the so-called "sharp pickles." Time up to one month or more pickled vegetables are can rest assured.
original, nitrite in vegetables from the relatively high nitrate content. Vegetables absorbed nitrogen or nitrogen in the soil, the accumulation of non-toxic nitrate, then preserved at the course, by some bacteria into toxic nitrite, resulting in trouble. Then, gradually began to nitrite by bacteria or by the use of decomposition, the concentration after reaching a peak will gradually decline, and even disappeared.
general, pickles nitrite up to appear in the beginning, when cured after 23 days to between ten days. Temperatures are high and low salt concentration, "nitrosourea peak" appears relatively early on; the other hand the temperature is low and salt big time, appeared relatively late on.
in northern China腌咸菜, sauerkraut usually more than one month at the south-cured sauerkraut, kimchi to 20 days or more, this time out and eat, on the whole are safe. Butter pickles traditional system is very long time, even up to several months, so not to worry about nitrite poisoning problem. Kimchi processing Strict isolation of oxygen can reduce the harmful substances produced, preserved among the add garlic to reduce nitrite production, a good process and we will reduce the risk of bacteria.
really dangerous, is that only 23 days pickled vegetables to ten days. Enjoy their own home to do some short-term point of pickles, but also enjoy the salad put入味eat for two days, these are unsafe practices. Because fish like to eat pickled cabbage dish, the repeated occurrence of nitrite poisoning cases, the main sauerkraut are not salted enough time to sell out in advance because.
to explain the third problem is that salt and sugar used to preserved foods, primarily to use them under high osmotic pressure can control the nature of micro-organisms, and to help generate the special flavor of the nature of taste. Demi-glace will not give rise to toxic substances, but to achieve long-term preservation of the effect of sugar content in order to achieve more than 65 percent, which would bring high-sugar high-calorie trouble. Saline to achieve long-term preservation of good results, also attain about 15% of the salt, taste Too heavy, but also have high blood pressure or suspects, they are currently the majority of products are sugar and salt pickles Ways to share and to reduce salinity, so that consumers easily accepted. But this kind of low-salt preserved foods saved an inevitable difficult, add preservatives thing is inevitable.
to explain the fourth problem is that the preserved foods to produce nitrite, on the one hand there is the temperature of salt time, on the other hand, also contains large quantities of raw materials which do nitrates. Duck, tofu is not like the food contains a lot of nitrate, so could not produce a lot of salted after nitrite, the adverse health factors of the salt itself is just too much.
However, because of water pollution in China is by no means uncommon, the seafood may contain more nitrite. Dried or cured, the part of one of the proteins are decomposed to produce amines and nitrites combine to become carcinogenic nitrosamines, are really questions that can not be ignored. Measurement showed that salted fish, dried small shrimps, dried sea goods, fish do, such as shredded squid nitrosamines have pollution problems, damp Taste products and fresh products are not particularly worrying.
Overall, according to Science and Technology of production, time to fully pickled kimchi, sauerkraut, pickles, pickled vegetables, such as North Korea will not cause food poisoning, on the human body are safe, but also to provide part of minerals and cellulose. No smell of咸鸭蛋, bacon, fermented bean curd, preserved fruit, etc. will not produce a large number of nitrosamines and other carcinogens.
However, compared with fresh products, preserved fruits and vegetables there is a greater loss of nutrients, salt or sugar content is too high, from the perspective of nutrition and health, or eating fresh fruit direct better .
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