Where do the bacteria on banknotes come from?

Although mobile payment is now very developed, people still have to come into contact with banknotes frequently in their lives. I believe many people have heard that the RMB is actually very dirty. Because banknotes have to pass through the hands of a large number of people, there will definitely be bacteria on the banknotes. This also reminds everyone to pay attention to the protection of banknotes and avoid bacteria on banknotes that endanger human health. So where do the bacteria on banknotes come from?

Where do the bacteria on banknotes come from?

Some people say that money is the dirtiest thing in the world. It has been touched by countless people during its circulation, and no one knows how many bacteria are on it. Many people believed this and even thought that coins could spread diseases.

Coins contain a lot of bacteria

Recently, a cashless alliance consisting of 15 domestic and foreign institutions including the United Nations Environment Programme, Alipay, and the Guangzhou Women and Children's Medical Center was established. It announced the test results of the City University of Hong Kong's previous research on mainland currency, showing that each banknote contains an average of 178,000 bacteria, and the number of bacteria attached to each of the 5-cent, 1-yuan, and 10-cent banknotes is as high as 18 million.

Don't scare yourself

It is true that banknotes carry fungi, but residents should not be afraid of them. Previously, a discovery in Oceania showed that the number of bacteria attached to banknotes is actually far less than people imagined.

Researchers from Australia and New Zealand conducted an experiment over a year. They collected 800 circulating banknotes from small food sales outlets such as cafes, butchers and bakeries and took them to the laboratory for analysis. The results showed that both coins and banknotes carried fewer bacteria than people imagined, and these bacteria were "useless guys" and were not enough to cause gastrointestinal diseases such as diarrhea and vomiting.

Researchers found that coins are cleaner than banknotes. There are only one or two bacteria per square centimeter on the coin, and some bacteria have no reproductive ability at all and cannot grow on the coin. The number of bacteria on banknotes is about 10 per square centimeter, and there are more species.

In this regard, the researchers explained that perhaps it is because the copper, arsenic, aluminum and copper used to make coins are toxic to many types of bacteria, and the bacteria cannot stay on the coins for a long time.

In addition, the researchers also found in the experiment that there are no fewer bacteria on credit cards than on banknotes and coins.

Coins are unlikely to cause disease

But the danger cannot be ignored. Studies have found that small amounts of bacteria, such as Escherichia coli, and Staphylococcus aureus, which can cause disease in people with weakened immune systems, are found on common banknotes and coins. In addition, the coins also contain Bacillus cereus, a bacteria that can cause food poisoning.

In addition, researchers also found traces of Salmonella on the coins. Most unexpectedly, the coins contained a variety of drug-resistant bacteria that were resistant to commonly prescribed antibiotics such as penicillin.

However, researchers say that although coins carry bacteria, these bacteria are no different from those carried on door handles or other public facilities. Therefore, there is no need to install a special sterilization spray device on the ATM. "As long as you take sensible precautions when cooking and handling money, it won't be a problem."

Bacteria on coins linked to climate

The number of bacteria on coins is related to the regional climate, because the climate affects the living conditions of bacteria to a certain extent. The RMB in Guangzhou and Chongqing is much dirtier than that in Beijing. This is because Guangzhou and Chongqing are located in the south where it is hot and humid all year round, while Beijing is relatively dry and cold.

Even if it is the same type of coin from the same region, the total number of bacteria on its surface will vary in different seasons. The maximum value occurs in summer, because the high temperature and humidity in summer make it easy for bacteria to survive, and the human body secretes a lot of sweat and oil, which easily attaches bacteria and dirt, causing cross contamination when contacting coins. As the temperature drops, the total number of bacteria attached to coins tends to decrease.