I'm not sure if you read the news about the pet food recall going on in the U.S.
Well I say you should be worried if you own a cat and/or a dog, we use the same foods sold in the U.S.
Some pet foods were found to have a certain chemical called melamine which caused the death of several cats and dogs. So if you really care about your pet, check here to see if the food you bought is on the recall list or not. They have thoughtfully provided Excel, Word and PDF documents to download & take with you to the supermarket whenever you're going to buy food for your pet.
Some great info on the tainted food can be found also here.
Good luck. :)