Canada’s food safety watchdog has urged caution after evidence of tampering was found in infant formula products in Edmonton.

The Canadian Food Inspection Agency posted a public advisory Tuesday after reports of “tampering by product substitution” at two Walmart stores in the city.

“Infant formula products have been found where the tamper-proof seals had been broken and the product inside the containers had been substituted,” the CFIA said in the advisory.

“This type of issue is not typically associated with the manufacturing process but can occur occasionally when a consumer returns altered products to the retail store for a refund.”

Consumers using infant formulas were advised to examine the packaging to ensure that the security seal is intact and has not been altered.

A mother who bought formula at the Walmart on 775 Tamarack Way Northwest noticed something wasn’t right with her purchase when she opened it at home.

“When I opened the formula I noticed the colour was off,” Emily Myrehaug told CTV News Edmonton.

“Usually it's a bright white powder and when I looked it was more of a brow- white. So I knew there was something off. I decided to sample it and of course then I could confirm it was flour.”

Luckily Myrehaug didn’t feed any to her five-month-old son and contacted the CFIA.

Police are aware of the incident and are investigating two cases of tampering.

The second tampered product was discovered at the Walmart on Calgary trail.

If a product appears to have been interfered with, the CFIA advises against using it and contacting local law enforcement or the CFIA.

There have been no reports of illness linked to the complaint, the CFIA said.