"Since I already touched it"... Can I drink the remaining water in the bottled water the next day?

Some people continue to drink from the same bottled water they drank the day before. It's easy to think it's okay because they don't share it with others, but in fact, drinking from the same water bottle like this poses a high risk of exposure to bacteria.

According to experiments conducted by the Korea Water Resources Corporation,

▲Immediately after opening the PET bottle cap, the number of bacteria per 1mL of water was one; after taking one sip, it was 900; and after one day, more than 40,000 bacteria were found to survive.

According to the "Rules on Water Quality Standards and Testing for Drinking Water," water that is not safe to drink is defined as water in which the number of bacteria exceeds 100 per 1 milliliter. A bottled water consumed after one day contains bacteria exceeding the standard limit by 400 times.

If you drink by putting your mouth on a PET bottle, saliva enters the water, and bacteria in the saliva rapidly multiply.

Water contaminated with bacteria can cause abdominal pain, diarrhea, food poisoning, and other illnesses. Especially during the hot summer days, bacteria reproduce more rapidly. It is known that a single bacterium can multiply to one million in just 4 to 5 hours. Furthermore, once a PET bottle is opened, there is a risk that bacteria present in the air may enter the bottled water.

Do not drink bottled water stored in PET bottles for more than one day.

If you cannot finish drinking all at once, you should pour and drink it from the cup before drinking. You should also refrain from reusing the remaining PET bottle after drinking water. In fact, when Seoul City tested 500mL bottled water reused at lodging establishments, bacteria exceeding 50 times the standard level were detected.

Meanwhile, even unopened bottled water can deteriorate over time. This is because some microorganisms in the water, permeable substances from outside, harmful substances caused by high temperatures or direct sunlight, and odors can all have an effect.

Therefore, the expiration date must be strictly followed.

The "Drinking Water Management Act" considers the expiration date of bottled water to be 6 months. Some bottled water imported from abroad can be distributed for up to about 2 years.