Police and health authorities investigated the Calgary Co-op store at Oakridge Centre after discovering food tampering. (CBC)

A Calgary grocery store has discovered more pins in its products, this time pushed into plastic juice bottles.

The Calgary Co-op store at Oakridge Centre in the city's southwest was closed for several hours Monday after pins were found in some bakery items. A sweep of the store by employees turned up more pins in bulk food items and in cheese.

On Tuesday morning, employees uncovered more of the pins.

"Before our centre opened this morning at Oakridge we did another sweep and we did find a couple of more products that have the metal objects in them. Those included some of our fresh juices in our produce department," said spokeswoman Sarah Boutron.

She doesn't know if the pins, which she describes as the kind used in sewing, were missed during Monday's sweep or are new.

Calgary Co-op did not receive any threats and the company doesn't know why anyone would tamper with food products, she said.

"We don't know why and that's why we have the police involved. It's a criminal investigation," she said. "We have upped our security. We have also made sure that all of our employees are looking out."

The store has recalled bulk food and bakery items, as well as packaged items. Customers can return suspect goods for a full refund.

There have been no reports of any injuries or problems at other Calgary Co-op stores.

"This is an isolated incident as far as we know. We have let our other centres know to be diligent in spotting these type of things," said Boutron.

Shoppers not concerned

Shoppers heading into the store on Tuesday weren't concerned about finding pins in their groceries.

"I was shocked, but it was handled very well. They shut the store down," said Helen Bennett. "It's just a sad commentary on what is happening in the world today."

Shopper Lisa Khamis said she wasn't surprised to hear about problems with bulk food bins.

"I personally tend to stay away from bulk food items, that is something I just do personally, I would prefer the packaged items," she said. "Anything could be dropped in there, whether it is hair, or insects, or anything."

She commended Calgary Co-op staff for acting so quickly on Monday.

"They did what they should have done. They let us know immediately, which is very important," said Khamis.