Ceramic tableware: don't choose glaze color.
Ceramic tableware has become the first choice for most families to buy tableware because of its diverse shapes, exquisite smoothness, bright colors and easy cleaning. However, the colored glaze on the ceramic surface may become a health killer. Lead, mercury, radium and cadmium in glass are all harmful elements to human body.
The production methods of ceramic tableware are divided into three types: over-glaze color, in-glaze color and under-glaze color. Over-glaze colored ceramics are made by pasting colored paper made of pigments on the glaze surface or painting directly on the surface of products with pigments, and then firing at low temperature. Because the firing temperature can't reach the melting degree of the glaze layer, the flower surface can't sink into the glaze. Touching the glazed porcelain with your hand, you feel that the flower surface has obvious concave and convex feeling. The firing temperature of colored porcelain in glaze can make the glaze melt, and the pigment can sink into the glaze. After cooling, it is covered by glaze layer, and the surface of the product is smooth, and there is no obvious concave-convex feeling by hand. All underglaze colored ceramics are decorated on the porcelain blank. After glazing, the surface of the flower is covered with glaze layer after a high temperature firing, which looks bright, flat and smooth.
Harmful metals mainly come from over-glaze pigments. Radioactive element radium can kill white blood cells. Cadmium, lead and mercury are all heavy metals. Cadmium and lead can cause liver or other visceral poisoning, and mercury can cause liver and kidney sclerosis. Long-term use of glazed tableware to contain foods with high organic acid content, such as vinegar, wine, fruit juice and vegetables, will lead to the dissolution of heavy metals in tableware and accumulate in human body with food, which will lead to chronic heavy metal poisoning for a long time.
In order to reduce the cost, some small ceramic manufacturers purchase cheap raw materials with high lead and cadmium content and unstable performance. In the production process, due to factors such as excessive decorative area, insufficient firing temperature or improper processing by workers, the lead dissolution of ceramic products will not meet the standard. Even some individual and private enterprises, in order to earn more profits, shorten the baking time or lower the baking temperature at will, and use the old baking furnace that relies entirely on workers' experience, which seriously restricts the quality of ceramic tableware.
Glass tableware: "Crystal glass" has many hidden dangers.
Glass tableware has the characteristics of high hardness, stable chemical properties, smooth surface, easy cleaning and environmental protection. Glass tableware is clean and sanitary, and contains no toxic substances.
Crystal glass tableware is a threat source of lead pollution. Because the lead oxide content in crystal products is as high as 20 ~ 30%, it will not cause lead poisoning when used to hold water, but if used to hold wine, the lead in crystal glass products will be dissolved by wine, and the longer it takes, the more it will be dissolved. Similarly, when food, especially acidic food such as cola, honey and fruit juice, is contained in crystal glass containers, lead ions are easy to form soluble lead salts, which are ingested by human bodies along with drinks or food, seriously endangering health. Therefore, crystal glass products are called "beauty killers" by scientists.
Through the above understanding, I believe we all know that tableware is generally not glazed, because glazed tableware is harmful to human health and easy to cause food poisoning and lead poisoning. Overglaze painting is usually a way of decorative ceramic painting. It is best not to glaze ceramic utensils that come into direct contact with the body. When choosing tableware, we also need to avoid using glazed tableware. If the tableware will fade, it is best not to use it, indicating that the lead content is relatively high.