Melamine

Melamine is a chemical commonly used in the manufacture of a wide variety of everyday household products, including dishes, utensils, counter tops, dry-erase boards, flooring, and wall paneling. Made of synthetic polymers like formaldehyde, melamine is usually found in the form of nitrogen-rich white crystals. Although generally considered harmless when in resin form, melamine can be dangerously toxic when ingested and combined with other chemical compounds. Melamine toxicity can ultimately lead to kidney stones, kidney failure, and even death. The potential dangers of melamine ingestion became clear in 2007 and 2008, when trace amounts of the chemical were found in pet food and instant formula made in China. This contamination led to thousands of infant illnesses and pet deaths. While melamine is not normally used as a food additive, its presence in certain plates, flatware, and other products that come in direct contact with food can lead to health problems under the right circumstances.

Background

Melamine was first developed in Germany in the 1830s. It is a derivative of cyanamide, a chemical that is used in the preparation of other chemicals. Melamine is a fine white crystalline powder. It is soluble in water and has a melting point of approximately 345°C. For practical purposes, melamine is typically heat and pressure-treated to create a resin that can be easily shaped and molded.

Since that time, it has been widely used in the manufacture of all sorts of plastic products, including plastic dishware. Lightweight and colorful, melamine dishware was enormously popular during the 1950s and 1960s but fell from favor after being supplanted by glass and ceramic dishware in the 1970s. Regardless, melamine dishware continues to be produced and is still used in homes around the world.

Melamine has many other uses as well. When combined with formaldehyde, it reacts to form a substance called melamine resin. Melamine resin is used in the manufacture of Formica countertops, foam paneling, dry-erase boards, flame retardants, and other products. A variant form of melamine called melamine poly-sulfonate is also used to increase the strength and durability of concrete. Melamine was even marketed as a fertilizer for a time, but never enjoyed wide use for that purpose because it performed poorly and was too expensive to produce.

One of melamine's most defining characteristics is its high nitrogen content. This particular characteristic eventually led to the development of melamine's notoriety as potentially dangerous substance. Chinese dairy producers sometimes add water to milk to increase its volume. As a result, this diluted milk ends up having a lower than normal protein concentration. Other Chinese companies that use this milk to make things like powdered baby formula routinely test the milk's protein level using a test that measures nitrogen content. Some of these companies started adding melamine to their milk to artificially boost its nitrogen content and make it appear that it contained more protein than it really did. This practice eventually revealed that melamine could be harmful and even deadly when ingested. This led to a public health crisis in the United States and China in the 2000s.

Overview

Concerns about the safety of melamine date back to the 1960s. At that time, veterinarians in South Africa began supplementing sheep feed with melamine under the mistaken belief that bacteria in the animals' gut could covert the chemical into biological proteins. In addition to proving that this assumption was incorrect, the experiment also showed that melamine was actually harmful when ingested in a large enough quantity. Many of the sheep that ingested melamine during the experiment became sick and some even died. Research has since shown that a by-product of melamine called cyanuric acid leads to the formation of dangerous kidney crystals. A buildup of these crystals can result in the formation of kidney stones or cause other irreparable damage that ends with kidney failure and death. Other possible symptoms of melamine poisoning may include inflammation of the skin and irritation of the eyes or mucous membranes.

Because of its high nitrogen content and the fact that nitrogen measurements are used to determine the amount of protein in various food products, manufacturers have often used melamine disguised as wheat gluten or rice protein so that they could overstate the amount of protein in their products. This practice led to a global health scare in 2007 and 2008 when it was discovered that Chinese manufacturers were adding melamine to various baby formulas and pet foods. In the United States, the addition of melamine to pet products resulted in thousands of pet deaths due to kidney failure. It also caused around 54,000 infants in Asia to fall ill with serious kidney problems and led to at least six deaths. As reports of melamine-related illnesses and deaths began to spread, the Chinese government was forced to issue a widespread emergency recall for the offending products.

Because of the chemical's potential danger, the Food and Drug Administration (FDA) does not approve the use of melamine for human or animal consumption and sets a strict limit on the maximum allowable melamine intake level. Since melamine is not normally used in food products, the biggest risk for melamine poisoning is the use of melamine-based tableware. Such tableware is not necessarily dangerous under normal circumstances. There is little to no risk associated with using melamine-based tableware to serve cold food or beverages or hot food or beverage that have been heated on or in something else. Melamine-based tableware is only potentially harmful when it is heated. Heating increases the likelihood that melamine will leach into food and be ingested accidentally. For this reason, it is important to note that melamine-based tableware should never be used in microwaves. Serving acidic foods on melamine-based dishware can also increase the likelihood of leaching. The potential toxicity of melamine is also dependant on the person ingesting it. Specifically, melamine is more dangerous to infants or children than it is to adults. As a result, children should never be served food or drink using melamine-based tableware under any circumstances.

Bibliography

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