UPDATE: Pet Food Maker Doesn't Know Why Food Killed 16 Animals

Pet food maker Menu Foods is no closer to finding the cause for the deaths of 16 animals.

Worried pet owners across the US and Canada are no closer to feeling at ease after pet food maker Menu Foods announced that no contamination was found in the 60 million products recalled Saturday. The company can't explain why at least 16 animals have suffered kidney failure and died after eating the food. Company executives have eluded to the fact they are looking at a certain ingredient but they didn't elaborate. The FDA is looking at wheat gluten, an ingredient that would not alone cause the kidney failure, but that could have been contaminated by molds or heavy metal toxins. "Our hypothesis is that it is that ingredient that in fact represents the highest probability as to the cause," Menu Foods CEO, Paul Henderson said. "But we have been unable to prove that through scientific information." The recall affected gravy-style pouches and cans sold at major retailers under 95 brands including Science Diet, Eukanuba, Iams and Nutro. "This is a puzzling and troubling experience for everybody within this organization," he continued. "It is extremely disheartening that we haven't been able to find the causative agent." Menu Foods is also coming under fire for hiring an outside company to test 40-50 animals with the tainted food. At least 10 cats and one dog have now died from kidney failure as a result of the testing. Menu Foods also had to explain why the company delayed announcing the recall for nearly a month after they learned there was a problem. Henderson said that the company had to be sure that the deaths were caused by ingesting their product. "Our hearts go out to all of the pet owners across Canada, the United States and Mexico for any losses they experience and certainly for the worry this incident may be causing," Henderson said. See related story: Pet Food