Chinese authorities have admitted that some ingredients used to make pet food did contain melamine. According to a report in USA Today this week, the admission led to increased investigations into two Chinese companies and their links to enormous animal food recalls here, which also noted that China claims melamine did not harm pets.

“There is no clear evidence showing that melamine is the direct cause of the poisoning or death of the pets … China is willing to strengthen cooperation with the U.S. side … to find out the real cause leading to the pet deaths in order to protect the health of the pets of the two countries,” Beijing’s Ministry of Foreign Affairs was quoted as saying by USA Today.  Meanwhile, USA Today reports that Chinese police sealed Binzhou Futian Bio-Technology’s headquarter offices; the company exports rice protein concentrate to the United States for use in pet food.

Melamine is an industrial chemical that has gained notoriety in recent years for its ability to cheat nutrition tests and was originally designed to make plastics, fertilizer and fire retardants.  Because melamine possesses high nitrogen contents, it can create the appearance in food of being high in protein and has been used in recent years to falsify protein levels in foods.

In the milk formula melamine-tainting scandal, the toxic chemical was added to watered-down baby formula to create the impression of high protein levels in the diluted milk products.  In the melamine scandal involving animal feed and food, melamine was likely added to the products for the same purpose.  Melamine can cause kidney problems — including kidney stones and kidney failure — when ingested.  Cyanuric acid has also been known to be added — with melamine — to wheat gluten added to pet food, reported USA Today.  Cyanuric acid is another industrial chemical and is used in swimming pools.  When added with melamine to food, the combination can create cystic growths in the kidneys and has proven fatal.

The U.S. Food and Drug Administration announced it will be going to China to conduct inspections; however, there is concern over that country’s “vast and fragmented food-processing industry.”