The Canadian Food Inspection Agency has warned people to inspect cans of powdered infant formula after two cans were found to be tampered with at a Zellers store in Saskatoon.

The cans of half-empty Enfamil brand baby formula were found to have puncture holes, concealed by the label. The agency said it is investigating and will decide whether to do any testing on the cans and their contents.

"Consumers using powdered infant formula products should look under the label to inspect the cans for signs of tampering," said a bulletin issued by the agency on Friday.

There have been no reports of illnesses since the suspect cans were found, the agency said.

The agency said the cans were likely punctured while in the store, rather than being returned products that were put back on the shelf.

A spokesperson for Mead Johnson, which manufactures Enfamil, said there had been no sign that any substance was poured into the cans and the tampering appears to be an isolated case.

An inspection of Mead Johnson products at other large retail stores in Saskatoon has not turned up any problems.

The company said a consumer bought the first can in January and reported the tampering to Mead Johnson, while a company official found the second can in February. 

In August 2006, the Canadian Food Inspection Agency issued a bulletin urging the public to inspect cans of powdered infant formula after four suspect cans were found at stores in Windsor, Ont.

One of the cans was found to contain what was believed to be a detergent. But in that case, there were no reported illnesses after the tampering was found.

With files from the Canadian Press