You could contact Iams and find out if you had a batch of the recalled food. It was a specific batch that was pulled right away. 5 weeks is also pretty young to be eating processed dog food. I had a dog once (I also got at 5 wks) that couldn't process the food well, so I made the rice n burger, yogert mix for her for a couple weeks before moving her over to dog food completely. Changing her food too fast could cause her problems so if you can, switch the food gradually.
Although Iams was a good food at one time, they've been changing the food and I don't care for it much anymore. I've been using it for years. I wish the better food wasn't so expensive cause I'd switch, but I feed almost 40 lbs a week to my dogs and 35-40$ a bag is pretty pricey as it is!