The impact of corrosion on the inner wall of a thermos cup on health: a hidden danger that cannot be ignored
In daily life, thermos cups have become a common drinking tool for people because of their convenience. Whether it is an office worker, a student or an outdoor enthusiast, a thermos cup has almost become a must-have. However, many people may not realize that the corrosion of the inner wall of a thermos cup may have many adverse effects on health. With the passage of time or improper use, the inner wall of the thermos cup is prone to corrosion. This article will explore in depth the various effects of corrosion on the health of the inner wall of the thermos cup.
Common causes of corrosion on the inner wall of a thermos cup
Corrosion of acidic substances: Many drinks are acidic, such as juice, carbonated drinks, lemonade, etc. When the thermos cup is filled with these acidic drinks for a long time, the acidic substances will react chemically with the stainless steel and other materials on the inner wall, accelerating the corrosion of the inner wall. For example, the carbonic acid in carbonated drinks and the citric acid and malic acid in juice will gradually precipitate the heavy metals in the stainless steel, while destroying the protective layer of the inner wall, resulting in aggravated corrosion.
The impact of high temperature environment: The characteristic of the thermos cup itself is to maintain high temperature, but this also creates conditions for corrosion of the inner wall. High temperature accelerates chemical reactions, making corrosion reactions more likely and faster. For example, when a thermos cup is filled with hot water for a long time, especially when it is close to boiling water, the dissolved oxygen content in the water increases, and these dissolved oxygen will react with the inner wall of the stainless steel to cause corrosion of the inner wall. Moreover, if there is still a small amount of acidic or alkaline substances left in the cup, the reaction between these substances and the inner wall will be more intense under high temperature conditions.
Improper cleaning: Some people may not have developed good cleaning habits, or use improper cleaning tools and detergents. If the thermos cup is not cleaned for a long time, the food residues and beverages left in the cup will ferment and deteriorate, producing corrosive substances such as organic acids, which will corrode the inner wall. Using rough steel wool or detergents containing strong corrosive ingredients to clean the thermos cup will also scratch the surface of the inner wall, destroy its protective layer, and make the inner wall more susceptible to corrosion.
Use of inferior materials: In order to reduce costs, some low-priced thermos cups use stainless steel materials that do not meet food-grade standards, such as 201 stainless steel. This material has poor corrosion resistance, and the content of chromium, nickel and other elements is insufficient to form a dense and stable passivation film to protect the inner wall. In contrast, high-quality 304 or 316 stainless steel contains an appropriate amount of chromium, nickel and other elements, which can form a dense chromium oxide film, which can isolate the contact between external corrosive substances and the stainless steel matrix, thereby effectively preventing corrosion. The inner wall of the thermos cup made of inferior materials is more prone to corrosion during normal use.
Various effects of corrosion on the inner wall of the thermos cup on health
Heavy metal precipitation is harmful to health: The inner wall of the thermos cup is usually made of metal materials such as stainless steel. When the inner wall corrodes, heavy metals such as chromium, nickel, and manganese in the stainless steel will precipitate. Excessive intake of heavy metals by the human body will have adverse effects on various organs and systems. For example, the accumulation of chromium in the human body may induce dermatitis and digestive tract problems, and long-term exposure may also cause cancer; excessive nickel can easily cause neurasthenia, system disorders, reduced fertility, and has strong teratogenicity and carcinogenicity; excessive manganese can reduce immunity and lead to loss of appetite. In severe cases, it may affect intelligence and even increase the risk of cancer and Parkinson's syndrome.
Breeding bacteria affects the digestive system: After the inner wall corrodes, it will form a bumpy surface. These depressions are easy to hide dirt and become a breeding ground for bacteria. If it is not cleaned for a long time or is not cleaned thoroughly, bacteria will multiply in large numbers in the thermos. When people drink the water in the thermos, these bacteria will enter the human body, which may cause gastrointestinal diseases such as indigestion, diarrhea, and vomiting. Especially for children with weak gastrointestinal function, the elderly and people with low immunity, the harm is more obvious.
Affecting the taste of drinks and reducing nutrition: The corroded inner wall will react chemically with the drinks, causing the drinks to have peculiar smells, such as rust and metal, which not only greatly reduces the taste of the drinks, but also may affect their nutritional value. For example, when using a thermos cup to make tea, the corrosion of the inner wall may destroy the beneficial ingredients in the tea leaves, making the aroma and taste of the tea worse; when filling milk, the chemicals produced by the corrosion may react with nutrients such as protein in the milk, reducing the nutritional value of the milk.
Release of harmful compounds to disrupt endocrine: The inner wall material or protective coating of some inferior thermos cups may release harmful compounds such as bisphenol A during the corrosion process. Bisphenol A is an endocrine disruptor that mimics human hormones and interferes with the normal function of the endocrine system, which may lead to a series of health problems such as reproductive system disorders, developmental abnormalities, obesity, and cancer. Especially at high temperatures or in contact with acidic or alkaline substances, the release of bisphenol A will increase, making it easier to enter the human body and pose a potential threat to health.
How to tell if the inner wall of a thermos is corroded
Observe the appearance: Check the surface condition of the inner wall of the thermos regularly. If you find brown or black rust spots, green or blue corrosion marks, or obvious uneven and rough areas on the inner wall, this may be a sign of corrosion on the inner wall. In addition, when the color of the inner wall becomes dull and loses its original metallic luster, it also indicates that there may be corrosion problems.
Smell: Open the thermos and smell it carefully for any peculiar smell. If you smell a pungent smell of rust, metal or chemicals, this is most likely due to the release of harmful substances caused by the corrosion of the inner wall. Under normal circumstances, a high-quality thermos should not have a noticeable odor after cleaning.
Check the sealing and insulation performance: Corrosion may damage the sealing and insulation performance of the thermos. If you find that the insulation time of the thermos is significantly shortened, or that the lid is prone to water leakage, this may be related to structural changes caused by corrosion of the inner wall. Because corrosion of the inner wall may affect components such as the sealing rubber ring inside the cup body, resulting in poor sealing and reduced insulation effect.
Methods to delay corrosion of the inner wall of a thermos cup
Use the thermos cup correctly: Avoid storing acidic or alkaline drinks for a long time, such as juice, carbonated drinks, Chinese medicine, etc. If you need to drink these drinks, it is recommended to use more suitable containers such as glass or ceramic cups. Do not use the thermos cup as a teacup to make tea for a long time. Pour it out and clean it immediately after drinking the tea. At the same time, avoid filling it with overheated liquids. It is best to wait until the water temperature cools down slightly before pouring it into the thermos cup.
Do a good job of daily cleaning: The thermos cup should be cleaned in time after each use. Use a soft sponge or rag with mild detergent to clean it. Avoid using rough steel wool or highly corrosive detergents to avoid scratching the inner wall. When cleaning, thoroughly clean the cup lid, cup mouth and every corner of the inner wall to ensure that there is no residual dirt. After cleaning, the thermos cup should be turned upside down to dry to avoid corrosion caused by water retention.
Choose a high-quality thermos cup: When buying a thermos cup, choose a well-known brand with good reputation, check the product logo, and make sure that its liner is made of food-grade 304 or 316 stainless steel. These materials have good corrosion resistance and can effectively reduce the possibility of corrosion on the inner wall. At the same time, pay attention to the process quality of the thermos cup, such as whether the welding is smooth and whether the surface treatment is fine. Good process can improve the service life and corrosion resistance of the thermos cup.
The corrosion of the inner wall of the thermos cup may seem to be a small problem, but it may have many adverse effects on human health. Therefore, we should pay full attention to this problem, and extend the service life of the thermos cup and ensure the health of our drinking water through correct use methods, daily cleaning and maintenance, and the selection of high-quality products.