The  Pet Food Institute  issued a statement June 30 in response to the  Environmental Working Group's study  of the amount of fluoride in 10 national brands of dog food, saying the report "makes a scientifically invalid extrapolation on the safe consumption level of fluoride for dogs based upon the established level for the water that people drink" and that it includes no new research beyond its own test results.

According to EWG, the study showed that eight of the brands contained fluoride amounts between 1.6 and 2.5 times higher than the US  Environmental Protection Agency's maximum legal dose in drinking water . The EWG questioned whether the levels of fluoride found in the foods were safe for pets.

"The biology of humans is very different from the biology of dogs," the PFI said in the statement, calling the report "high on sensationalism, low on fact."

The EWG also claimed that bone meal and animal by-products were the "likely source of the fluoride contamination" and suggested that dog owners purchase petfoods that do not contain bone meal and other animal by-products to "protect pets from excessive fluoride exposures."

"Many petfood products contain bone meal and other animal by-products because they are critical sources of quality nutrition for dogs," the PFI's statement read. "Bone meal and other animal by-products are allowed for use in dog food by the US Food and Drug Administration and the US Department of Agriculture, the same agencies that regulate human foods."

To view the PFI's full statement, click  here .