The bottled water has been opened for three days. Is what you drink really bacteria?

Is it true that bottled water is "surrounded" by bacteria three days after it was opened? Are we really drinking bacteria when we drink water? Let's take a look at the most terrifying pathogenic bacteria behind drinking water safety.

Text/Reporter Li Li New Media Editor/Chen Xuanzhi

Interview experts:

Li Fuxing (Director of Beijing Public Health Drinking Water Research Institute)

Zhao Feihong (Director of the Healthy Drinking Water Professional Committee of Beijing Health Protection Association)

gossip:

Three days after the bottled water is opened, the bacteria will increase 227 times. Some netizens said: Drinking water like this is drinking bacteria.

the truth:

It is not that scary to leave bottled water for three days. The rumor on the Internet that you can drink bacteria is a bit alarmist. However, after the bottled water is opened, the number of microorganisms will increase gradually, but it does not affect drinking in general.

The proposition that the bacteria in bottled water exceeds the standard after opening is not accurate. Li Fuxing, director of the Beijing Public Health Drinking Water Research Institute, told reporters that it is two different concepts: whether the bacteria in the bottled water itself exceeds the standard after opening the lid, or whether the bacteria in the water flowing out of the water dispenser exceeds the standard. Generally speaking, the bacteria in bottled water itself will not exceed the standard, because my country has strict control over this and has relevant standards to restrict it. Counting from the date of the bottled water leaving the factory, it is difficult for qualified mineral water to exceed the standard within three days of opening.

At present, bottled water is usually used with water dispensers, and the bacteria in bottled water exceeds the standard due to secondary pollution of the water dispenser itself. In particular, the long-term exposure of the water outlet of the water dispenser is prone to excessive bacteria.

Li Fuxing said that in fact, the correct statement should be that bottled water is prone to microbial contamination after opening. The degree of microbial contamination depends on the type and source of water, the degree of pollution in the surrounding environment, and the length of storage time. Different water sources and water quality will have slightly different bacterial content.

At present, purified water is more polluted than mineral water. Mineral water refers to water that naturally gushes from deep underground or is collected through drilling, and contains a certain amount of minerals, such as calcium, magnesium, potassium, sodium, metasilicic acid, zinc, selenium, etc. The country has requirements for the content of some trace elements, for example, zinc must be greater than or equal to 0.2 mg/L, and selenium must be greater than or equal to 0.01 mg/L. Purified water is water that is directly derived from the surface, underground or public water supply system, and is made through appropriate water purification and processing methods. Compared with purified water, mineral water has stronger antibacterial ability and stronger anti-pollution ability. Therefore, it is recommended to choose mineral water and drink it as soon as possible after opening.

Li Fuxing introduced that water is closely related to human survival. Due to the strong solubility, strong solubility, strong penetration and other characteristics of water, and the fact that water can penetrate everywhere, various "invisible" pollutants are threatening our health all the time and everywhere through water. The safety of water is more prominent than general food safety. At present, many countries in my country no longer use the total number of colonies as the standard for whether water is drinkable, but focus on the situation of pathogenic bacteria in the water.

The new national standard "National Food Safety Standard for Packaged Drinking Water" (GB19298-2014), approved and issued by the National Health and Family Planning Commission (now the National Health Commission) on December 24, 2014, added the detection of pathogenic bacteria and specifically cancelled the detection indicators of total bacteria, mold and yeast counts, etc. In addition to retaining the coliform group indicator, the new national standard added the Pseudomonas aeruginosa indicator.

This is mainly because the total colony count, mold, and yeast are sanitary indicator bacteria, which generally do not affect public health. However, excessive control of sanitary indicator bacteria and sterilization may lead to an increase in the bromate content in drinking water, posing a health risk. At present, the relevant standards and regulations of the United States, Australia, and the European Union do not set sanitary indicator bacteria indicators for packaged drinking water.

The reason why the national standard for packaged drinking water adds Pseudomonas aeruginosa as an inspection item is that Pseudomonas aeruginosa is pathogenic. Failure to meet the Pseudomonas aeruginosa inspection standard may cause diarrhea, acute enteritis, skin inflammation and other diseases in consumers.

The national standard also clearly states that Pseudomonas aeruginosa must not be detected in every 250mL water sample, and requires that each batch of finished products be tested for Pseudomonas aeruginosa before leaving the factory. If detected, it is considered an unqualified product and should be recalled and sales stopped.

Zhao Feihong, director of the Healthy Drinking Water Professional Committee of the Beijing Health Protection Association, believes that compared with the excessive total number of bacteria, the more terrible are the pathogenic bacteria. In fact, since the new national standard added Pseudomonas aeruginosa as a new inspection item, packaged drinking water products in various places have repeatedly failed the Pseudomonas aeruginosa project, which has become a "chronic disease" in the drinking water industry. The detection rate of Pseudomonas aeruginosa in the water of some small water plants in the south is quite high. For the water produced by these manufacturers, the number of bacteria will seriously exceed the standard without opening the bottle.

Pseudomonas aeruginosa is one of the common bacteria, often found in humid environments such as soil, water, and air. It is a conditional pathogen that can cause disease under certain conditions such as reduced body resistance. The reasons for the failure of Pseudomonas aeruginosa in drinking water may be: first, the raw water is infected; second, the hygiene control in the production process is not strict and the sterilization is not thorough; third, the cleaning and disinfection of packaging materials are defective.

For consumers, it is recommended to buy bottled drinking water produced by big brand manufacturers and drink it within one week after opening. Secondly, in daily use, it is best to clean and disinfect the water dispenser once every three months to avoid the growth of harmful bacteria.

Regarding the problem that it is difficult for consumers to directly test the safety of drinking water, Zhao Feihong pointed out that you can simply "look" and "taste" to preliminarily determine whether drinking water is contaminated by bacteria. You can turn the bottled water upside down and observe whether there are floating objects in the water. If there are floating objects in the water, then the water is definitely contaminated by microorganisms. In addition, if the drinking water has a taste, such as a fishy smell of earth or a sour smell, then the water is definitely contaminated by microorganisms and it is recommended not to drink it.

Produced by: Science Central Kitchen

Produced by: Beijing Science and Technology News | Science Plus Client

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