Food Fraud - Chemical Hazard: Melamine

Food Fraud - Chemical Hazard: Melamine

 

Melamine

Melamine is a synthetic triazine compound and an organic base with the chemical name 2,4,6-triamino-1,3,5-triazine and is high in nitrogen (C3N6H6).

Melamine is widely used in plastics, adhesives, countertops, dishware and whiteboards.

Sources and Occurrence in Foods: Melamine contamination in food first became a food safety issue when the chemical was detected in pet foods. An investigation showed that melamine was found in wheat gluten and protein concentrate exported from China and was used as a thickening and binding agent within the pet food.

It has also been found in animal feed samples, orange juice and coffee. In 2008 it was also found in dairy products from China, an example being powdered milk to make infant formula.

Melamine is illegally added to inflate the apparent protein content of food products. Because it is high in nitrogen, the addition of melamine to a food artificially increases the apparent protein content as measured with standard tests. This would give a falsely high result in tests designed to determine protein content and cause the material to be assigned a higher quality rating and commercial value (food fraud). It has been estimated that the addition of 1 g of melamine to 1 litre of milk would raise the apparent protein content by approximately 0.4%.

It may also come from other sources especially plastic packaging or processing equipment but usually only at levels not harmful to health.

Effects on Health: Data from animal studies can be used to predict adverse health effects. Melamine alone causes bladder stones in animal tests. When combined with cyanuric acid, which may also be present in melamine powder, melamine can form crystals that can give rise to kidney stones. Acute renal failure or confirmed renal stones

These small crystals can also block the small tubes in the kidney potentially stopping the production of urine, causing kidney failure and, in some cases, death. Melamine has also been shown to have carcinogenic effects in animals in certain circumstances, but there is insufficient evidence to make a judgement on carcinogenic risk in humans.

Symptoms and signs of melamine poisoning include irritability, blood in urine, little or no urine, signs of kidney infection and high blood pressure.

Melamine being recognized as a contaminant, Codex has specified the following maximum limits for melamine in various foods:

Food (other than infant formula) : 2.5 mg/kg  

Powdered infant formula: 1 mg/kg  

Liquid infant formula: 0.15 mg/kg

Control Measures:

Sourcing

Food manufacturers should exercise caution when souring ingredients. Traceability to the point of origin is essential. Materials such as milk powder, dried egg powder and high-protein ingredients should be purchased only from known low-risk sources.

Testing

The only practical control for Melamine in foods at present, other than careful sourcing, is testing analysis of all ingredients that carry a risk of contamination.