Is it true that drinking yesterday’s tea is dangerous for health?

There is an opinion that tea, which has stood at room temperature for a long time, cannot be drunk, since substances harmful to health are formed in it. We decided to check if this is so.

In the Russian -language segment of the Internet, you can find many articles that drinking yesterday is harmful. IN Blogs, on sites medical organizations and in Media The authors give a Japanese proverb: "Cold tea is worse than a snake bite." Articles About the dangers of tea brewed on the previous day, you can find on many specialized Portals. In some sources it is not only about yesterday, but even about just cooled tea - supposedly drink it Can Only within 15 minutes after brewing.

We are already They wrote The fact that tea is black, that green is very useful. However, does it always remain like this or the brewed tea also has an expiration date?

The film, which is formed on tea tea leaves after some time, can really cause concern. The opinions of scientists about what kind of film it is and why it is formed, dispersed. One They saythat the bicarbonate of calcium, contained in hard water, is to blame for everything, which, mixing with polyphenols - the most useful part of the tea - and forms that same rainbow film. Other inclined To the version that this film is essential oils from leaves that have been released into the water and emerged to the surface. But whatever the formation of this film is connected with, we could not find scientific research that would confirm that it is harmful to health. 

What can really be dangerous yesterday’s tea is bacteria that can begin to multiply in it at room temperature. In the tea leaves themselves no dangerous substances are contained, but bacteria can get there during production, transportation, storage and preparation. Therefore, experts Consult Bring tea and herbal infusions, which are also often called teas, boiling water, as this will help destroy most of pathogens. However, even in this case it turned outthat in tea, brewed more than 16 hours ago, E. coli begins to breed actively, which can really be dangerous to health. Moreover, if the temperature of the brewing of tea was not high enough, the shelf life may be even less.

The type of tea also affects the shelf life. So, biologists conducted experiment, during which three types of tea were taken (black, oolun and white), brewed with boiling water and left it in sterile containers at room temperature for two days. Even under such laboratory conditions that are clearly not respected at home or in catering establishments, bacteria began to multiply in white tea and oolun. Scientists associate this with the degree of oxidation of tea - in the most oxidized black tea there were no visible changes after two days, in white, which did not oxidize at all, there were most bacteria.

If you still feel sorry to pour tea, it is better to put it in the refrigerator at night, since the "room" temperature Creates Great conditions for the propagation of bacteria. In conditions from 4.5 ° C, to 60 ° C, the number of these microorganisms grows exponentially - twice in 20 minutes. If we are not just about brewing in a teapot, but about the finished drink to which they added sugar or milk, then its storage period outside the refrigerator is even less, since these additives can create an even more nutritious environment for bacteria.

Adviсe You can store brewed tea for no more than eight hours Meet On many Portalsspecializing in this drink: It says both about the danger of bacteria propagation, and that over time, the taste and aroma of tea deteriorate. Some sites even Reference on recommendations Centers for the control and prevention of US diseases not to drink tea, which stood for more than eight hours outside the refrigerator, but we could not find their source.

Thus, tea can really deteriorate and then becomes harmful to health, especially if mold has already begun to form in it. However, for this it must be kept at room temperature for quite some time. Bacteria begin to multiply faster than mold, and really represent some danger to the body. In general, tea, brewed more than eight hours ago, is really not worth drinking - at least because it loses its taste. But to call such a drink to the poison is still an exaggeration.

Half truth

What do our verdicts mean?

Read on the topic:

1. Is it true that green tea is more useful than black?
2. Is it true that boiling water “kills” the beneficial properties of tea?
3. Is it true that drinking during food is harmful to digestion?