Since the emergence of dish soap in China in the 80s of the last century, it has become the preferred stain remover for the majority of people to wash dishes by virtue of its efficient cleaning ability. However, in recent years, many people believe that long-term detergent residue is a major reason for the high incidence of cancer in China. Are dish soap residues really a health hazard? How do we remove residue from dishes and chopsticks?
First of all, let's talk about the fact that after washing the dishes with dish soap, no matter how many times you rinse, you can't completely remove them, and we wash the dishes at home at most two or three times, so it is common for there to be residues in the dishes and chopsticks.
In order to find out how much dish soap remains in our daily dishwashing, experts have done a related experiment.
The experimenter first took out three porcelain bowls of the same size and material, labeled them No. 1, No. 2 and No. 3 respectively, and then added different brands of dish soap, adding 5ml to each bowl at the same time, and then left for 1 minute. Then start rinsing with household taps with the same amount of water for half a minute, until there is no foam at all, and then take separate samples for testing. As a result, the experimenters found that the residual amount of dish soap in each bowl was 0Above 10mg cm, the monitoring data of the three groups were 012mg/cm.11mg/cm.15mg/cm²。
Subsequently, the experimenters washed the bowls to varying degrees, the first one washed twice, the second one washed five times, and the third one washed 20 times. Each rinse is 10 seconds.
After the rinsing, the experimenter added reagents to the three bowls for testing, and after a series of complex operations, the test results were obtained:
After rinsing twice, the residual amount of dish soap in the bowl was reduced to 006mg cm, which is about half of the drop; After rinsing the porcelain bowl 5 times, the data has dropped to 001 mg/cm²；Even after 20 rinses, the amount of detergent residue detected is negligible, but it still cannot completely remove the residual detergent components.
However, according to the GB14934-1994 national standard, the residue of detergent should be less than 01mg cm, it can be seen that as long as you carefully rinse the dishes and chopsticks more than twice, then the dish soap residue will not be too much.
"Dish soap residues are mixtures of non-toxic or low-toxicity chemicals that do not cause much harm to the human body as long as they are below national standards," the expert explains. Eating with a bowl with low dish soap content for a long time may not cause as much harm as eating barbecue, let alone cause cancer. ”
But in fact, cleaning delicate cancer is not groundless. When a series of cleaning products such as dish soap and laundry detergent were just formed in China, it was more than 30 years ago. At that time, due to the lack of conditions in all aspects, the testing standards of dish soap were not very high, and there were really some carcinogens, such as formaldehyde, which we are more familiar with.
Detergent is not only an active substance that can remove oil stains, because it is a commodity, it must compete with other brands of products on the market, and it is bound to improve its competitiveness in terms of shelf life, cleaning effect and quality. And preservatives are an indispensable thing.
In the last century, when clean preservatives were not produced, formaldehyde was the only choice for many businesses. If formaldehyde is not added, the preservation of dish soap will be a big problem. After the production of clean preservatives, the phenomenon of adding formaldehyde to dish soap still exists, because as an old preservative, it not only has a good effect, but also the most important thing is that it is cheap, and it is favored by many businesses. However, the country's action is also very fast, and the formaldehyde detection standard of dish soap has been improved a lot, so although the current dish soap still contains a small amount of formaldehyde, as long as the dishes are washed carefully, there will be no problem.
In addition to formaldehyde and preservatives, dish soaps also contain fluorescent brighteners and dioxanes, a possible carcinogen. In order to let readers intuitively feel the main ingredients of dish soap, here is a quote from Consumer Reports' test report on 13 major dish soaps on the market.
* The number in the number is not the amount of chemical substances, but the experimenter's scoring criteria, that is, the higher the score, the stronger the detergency, or the less chemical additives it contains, and it is a perfect score of 10.
It can be seen that the methanol, formaldehyde and fluorescent brighteners of the 13 products all meet the standards, so they are all 10 points. However, there is a big gap between the content of dioxane and preservatives and the cleaning ability.
It is worth mentioning that MIT (methylisothiazolidone), commonly used in dish soap preservatives, has the potential to be sensitized, and common adverse reactions include itching, rash, and in severe cases, it may also lead to contact inflammation. The American Contact Inflammation Association once rated MIT as the "Allergen of the Year", so friends with allergies should still wear gloves, choose dish soap with less preservatives, or simply let their family members wash the dishes for them.
Although dish soap residue is not very harmful, it has to be prevented, and there are many common wrong ways to wash dishes at home.
For example, put the dishes and chopsticks in a large basin and wash them together, or soak the dishes for a longer time before washing. Many people think that after soaking the bowl for a long time, the oil stain will naturally fall off, which is more labor-saving than washing it directly. Another friend said: "Washing dishes is really annoying, I usually soak the dishes and chopsticks in water and put them in a good mood before washing." ”
But what you don't know is that as you soak the bowl in water, the bacteria will increase in size and then begin to multiply in a geometric progression. If the bacteria reproduce for one generation every 20 minutes, 1 bacterium becomes 8 in 1 hour, then it will become more than 1 billion after 10 hours.
Someone said, "I'll just take a basin of water and wash it directly, and leave it all night, so there will be no bacteria now, right?" ”
It's true that bacteria don't grow easily, but at the same time, the dishes can't be washed clean.
The Kunming National Food Safety Demonstration Team conducted a detergent residue experiment, and the testers washed the dishes with basin water and faucet rinsing, brushing the basin water twice, rinsing it once with running water, and rinsing it with running water for 30 seconds. After removing the dish soap residue, samples were taken separately.
The results showed that the basin water was rinsed once, and the residue was the highest, and the estimated measured value was about 0081mg per 100 square centimeters, the residue of washing twice with potted water, and simply rinsing with running water once also exceeds the national limit.
Only the sodium dodecylbenzene sulfonate measurement for 30 seconds rinsed under running water, less than 0005mg per 100 square centimeters.
It can be seen that rinsing with the faucet makes it easier to flush off the residue of dish soap.
The third mistake is to wash the dishes in cold water. It is very troublesome to boil water to wash dishes in winter, and some people simply wash them directly with cold water, but washing dishes with cold water has great disadvantages. First of all, because the oil molecules of dish soap are more active at high temperatures, hot water makes it easier to clean dishes and chopsticks. At the same time, washing dishes with cold water for a long time is also prone to "dishwashing disease".
On November 29, 2021, according to reports, a middle-aged woman in her forties and fifties in Fuzhou, Fujian Province, suddenly felt numb and painful in both hands. After a doctor's examination, it was found that the woman was suffering from "dishwashing disease".
Because she often washes dishes with cold water at home, and washes dishes repeatedly every day, her hands are constantly doing mechanical movements, which causes her hand muscles to swell due to cold water stimulation. In addition, the weather is getting colder, and the hands feel numb and weak. Therefore, it is very important to wash dishes in warm water.
Nowadays, dish soap has reached a high standard of safety as our daily necessities, so there is no need to worry too much. Instead, we should do more to correct some irrational dishwashing methods.