Purina® Cat Chow® is happily advertising "New and Improved Shapes!"

The new formula boasts a bright red heart, dyed with Red Dye #40. Red Dye #40, a petroleum-based dye is a possible carcinogen, and has been implicated in instances of stomach upset and allergies in our beloved animal friends.

Purina claims that its dye is USDA (actually FDA) approved. It's apparently red dye #40, also known as Allura Red AC, an azo dye made from coal tar. The FDA approves things that humans eat, and does no testing on the effects of food additives upon wildlife. It is a mistake to assume that animals are affected by chemicals in the same way as humans; in fact, our physiologies are quite different.

But what if it were approved? Tylenol is FDA approved, but feed it to your cat and it will die (acetaminophen is highly toxic to cats). Some humans are sufficiently allergic to red dye #40 that mere contact will send them into shock. Further, the FDA recommends that humans do not ingest large quantities of a single dye product, but with the different colors in the "improved Cat Chow", each fancy shape can be assumed to contain Red Dye #40.

Despite the FDA approval of red dye #40, enough scientific evidence has accumulated that it has been banned in a number of countries. See these links: