Canada's food watchdog is exploring possible links between a spate of food-tampering incidents in Alberta and a piece of metal a Vancouver man found in a store-bought sandwich.

Even though Fabian Picco says he'd heard of incidents in Calgary involving metal placed in fruit, bread and ground beef, the last thing he expected when he bit into a prime rib sub at a Burnaby Quiznos was a two-inch-long metal strip.

"I grabbed the front end of the steel with my teeth, and I held onto it, and I pulled it out," he told CTV News.

"What do you do? You never expect to see steel in something you're eating," he said.

Quiznos told CTV News in a statement that it doesn't know how the metal could have come from their bakeries.

"We're taking this matter very seriously and have launched a full scale investigation," wrote spokeswoman Allison Riley.

Picco called the Fraser Health authority, which ordered the Quiznos, at 4204 Hastings Street, to dump all of its bread loaves.

But when the agency found out the bread had been baked in Calgary, it informed the Canadian Food Inspection Agency.

Over the past few months in Calgary, there have been several incidents of metal objects being placed in bread, fruit and ground beef in different grocery stores.

"You've got to be really sick to think that's a fun thing," said Calgary Police Chief Rick Hanson at the time.

A woman was charged with mischief, but police suspect copycats are still at work.

Quiznos has asked Picco to bring the metal to them so they can examine it. Picco is still holding onto the metal fragment, saying that he'd rather a public agency look directly into the matter.

"I would follow the full chain of production of the food," said Picco. "You have to go back to the supplier. Where is it vulnerable to have lethal sharp pieces of steel fall into the food?"