Chongqing morning post reporter Liu Bo reports.

　　Is natural mineral water really natural and pollution-free? The more expensive the mineral water, the better the quality? Recently, chongqing morning post, together with Consumer Report magazine, sent 12 kinds of packaged drinking water of 10 brands to an authoritative third-party testing agency for inspection.

　　Among them, there are 7 kinds of natural mineral water including Nongfu Spring, Kunlun Mountain, 5100 Tibet Glacier, Jingtian Baisui Mountain, Uni-President alkaqua, France perrier, Danone Yili, 4 kinds of infant water including Nongfu Spring, Jurassic, Bay Blue and Santa Anna, and one kind of natural water of Nongfu Spring.

　　We will tell you that the quality of mineral water is not directly proportional to the selling price by comparing the results of N1 index, TOC, total phosphorus, sodium, taste index and total number of colonies.

　　Evaluation report 1 is pollution-free.

　　The water in 1.5 yuan is better than that in 27 yuan.

　　In many people’s minds, the sign of good water is "natural and pollution-free". Therefore, we first determined the N1 index, total phosphorus and total organic carbon (TOC) of 12 kinds of packaged drinking water. According to WHO regulations, the sum of the ratio of nitrate measured value to standard value and the ratio of nitrite measured value to standard value in water should be less than or equal to 1.

　　"A large number of data surveys have found that the total amount of nitrate nitrogen in natural high-quality mineral water and natural mountain spring water in nature is less than 0.5." Professor Li Fuxing, Director of Beijing Public Health Drinking Water Research Institute, introduced.

　　"So we take 0.5 as the critical value of’ good water’. We named this formula N1 index. " Li Fuxing said that the conversion formula of N1 index is N1= nitrate measured value/standard value+nitrite measured value/standard value. The greater the value of N1, the more seriously the water quality of the water source is polluted.

　　The results showed that the N1 index of 12 kinds of packaged drinking water was below 0.5, which met the requirements of WHO for good water. In addition, no total phosphorus and total organic carbon were detected in all the packaged drinking water, indicating that the water source was less polluted.

　　The N1 index of Bay Blue natural mineral water from New Zealand was only 0.021, while the N1 index of Jurassic natural mineral water reached 0.376.

　　The N1 index of Danone Yili’s drinking natural mineral water source, which is only sold in 1.5 yuan, ranks second, which is more pollution-free than perrier natural mineral water sold in 27 yuan.

　　Evaluation Report 2 Taste

　　Water with the right mineral content is really "a little sweet"

　　The slogan "Nongfu Spring is a little sweet" has made many people begin to notice the taste of packaged drinking water. However, there are no relevant standards and quantitative tools for evaluating the taste of packaged drinking water.

　　After investigating and analyzing the mineral components in tap water and drinks in the world and Japan, the scholars of Osaka University in Japan think that the taste index is closely related to five components: calcium, potassium, silica, magnesium and sulfate, and put forward a formula for evaluating the taste of drinking water: the taste index oi = (Ca2++K++SiO2)/(Mg2++SO4 2-) ≥ 2.

　　According to the formula, the taste of water is positively correlated with the taste index. The higher the value, the sweeter the water is, and "2" is the critical value of taste.

　　"The higher the content of calcium ions, the thicker the taste of water. A proper amount of potassium ions can make water sweeter, and silica is also conducive to improving the taste of water. Too high content of magnesium ions and sulfate will make water bitter and astringent. Only when the contents of these five ions are in a relatively balanced range will the water become sweet, thick and delicious. " Zhao Feihong, director of the Drinking Water Professional Committee of Beijing Health Protection Association, explained.

　　According to the formula of taste index, we measured the taste of 12 kinds of packaged drinking water. The taste index of 9 kinds of water is higher than 2, and the best taste is Danone Yili drinking natural mineral water and Jingtian Baisuishan natural mineral water, with the taste indexes of 16.35 and 14.07 respectively.

　　The taste index of Jurassic natural mineral water (infant water) was 0.31, and that of 5100 Tibetan glaciers was 1.43, which did not meet the minimum recommended index of taste index.

　　Evaluation Report 3 Sodium Content

　　Three kinds of water should not be drunk by special people for a long time.

　　Scientific research shows that excessive salt intake is easy to cause diseases such as hypertension, myocardial infarction and cancer. The main component of salt is sodium chloride, so controlling salt intake is actually controlling sodium intake.

　　"For special people, such as infants, the elderly, hypertensive patients, and people with low immunity, the sodium content in drinking water should not exceed 20mg/L. Only water with sodium content below 20 mg/L can be called low-sodium water." Professor Li Fuxing, director of Beijing Public Health Drinking Water Research Institute, said.

　　After testing, the sodium content of 9 of the 12 kinds of packaged drinking water sent for inspection is lower than 20mg/L, of which the sodium content of natural mineral water of Bay Blue is only 1.32 mg/L..

　　The sodium content of Jurassic, 5100 Tibet Glacier and Kunlun Mountain mineral water was higher than 20mg/L, among which the sodium content of Jurassic drinking natural mineral water reached 154 mg/L. For special people, if they drink it regularly, it will have a certain impact on their health.

　　Evaluation report 4 Total number of colonies

　　Is infant water a concept?

　　In recent years, water under the banner of "mother and baby water" and "baby water" has quietly become popular in the market. However, in China, there is no relevant standard for such new concept aquatic products. Judging from the current market situation, the concept of "sterility" is the mainstay of most infant water. So, is "sterility" reliable?

　　We specially sent four kinds of infant water, including Nongfu Spring drinking natural water (suitable for infants), Italian Santa Ana baby mineral water, Bay Blue natural mineral water and Jurassic drinking natural mineral water, and compared two kinds of packaged drinking water of Nongfu Spring within the brand.

　　In fact, there are no restrictions on the total number of colonies in the existing national drinking water standards GB 8537-2008 Drinking Natural Mineral Water and GB19298-2014 Packaging Drinking Water. The only requirement for the total number of colonies is GB5749-2006 Hygienic Standard for Drinking Water, with a limit of 100cfu/ml.

　　According to the test results, the total number of colonies in Santa Ana baby mineral water in Italy is less than 1cfu/ml. The total number of colonies in Bay Blue and Jurassic reached 176cfu/ml and 1900cfu/ml respectively.

　　Interestingly, compared with the products in Nongfu Spring brand, the total number of colonies in natural water and natural water specially marked for infants and young children is less than 1cfu/ml. In other words, before Nongfu Spring introduced the concept of "aseptic" infant water, the products had been "aseptic".