On cold days, taking a thermos outdoors is truly ideal. With a thermos, food and drinks can stay hot for longer, and if we use high-quality thermoses, they can maintain the temperature of the food for 12 to 24 hours.
However, to ensure health safety and maintain the durability of the thermos, experts warn to remember a few important notes below.
Avoid Using Thermoses for Acidic Liquids
Regarding thermoses, Associate Professor Dr. Tran Hong Con (Department of Chemistry, University of Science, Vietnam National University) stated that most thermoses are made of stainless steel. This stainless steel layer not only enhances the ability to keep food warm but is also safe for users.
Acidic liquids can trigger the release of heavy metals in stainless steel, leading to chemical reactions.
However, this stainless steel can react with acids. Therefore, you should not use thermoses or any stainless steel items to hold acidic liquids such as: fruit juice, apricot soaking water, sour apple water, soaked strawberry water, soaked soursop water… or dishes like pickled vegetables, pickled eggplant, sour soups. These liquids and dishes can stimulate the release of heavy metals in stainless steel, resulting in chemical reactions, which may produce carcinogenic substances, or at the very least cause stomach pain and poisoning.
Mr. Con believes that thermoses used to hold plain water, tea, or warm/hot water pose no issues, and consumers can use them with confidence.
How to Choose a Safe Thermos?
Just taking a look around the online market, it is not difficult to find thermoses at various price points and diverse in design and type. Therefore, many people feel quite confused when selecting a safe, quality thermos. This is not to mention that some low-quality thermoses have previously been reported by authorities for containing asbestos in their bodies.
According to Associate Professor Dr. Tran Hong Con, manufacturers typically use asbestos between layers of stainless steel to improve insulation. In cases where the thermos material is poor, asbestos can leak out, entering the bronchi and causing lung cancer and other serious health issues.
A good thermos will have a thick insulation layer, feel slightly heavy, have a sturdy base, and a shiny metal exterior…
“The first step to safely using a thermos is to choose a high-quality product. Good thermoses will have a thick insulation layer, feel slightly heavy, have a sturdy base, and a shiny metal exterior. The plastic cap should be made from virgin plastic, which does not emit unpleasant odors when exposed to heat. Additionally, choose products from reputable brands that have been safety tested and trusted by many users,” the expert advised.
Some Notes When Using a Thermos
- 1. When using a thermos, do not abruptly change the water temperature from hot to cold and vice versa, as this can affect the quality and lifespan of the thermos. If you wish to switch from cold to hot water or vice versa, let the thermos return to room temperature for about 10-15 minutes before replacing the water.
- 2. Absolutely do not attempt to break or disassemble thermoses to avoid asbestos release.
- 3. Do not place thermoses in the microwave or refrigerator. If the thermos is dented or damaged, do not continue using it.
- 4. After each use, when cleaning the thermos, turn it upside down to prevent rust from water accumulation inside and help it dry faster.
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