Police and health authorities investigated the Calgary Co-op store at Oakridge Centre after discovering food tampering. (CBC)A Calgary grocery store has reopened after temporarily closing when employees discovered some products had been tampered with and might contain small metal pins.

Police and health authorities conducted an investigation at the Calgary Co-op store at Oakridge Centre in the city's southwest.

The store was shut for several hours Monday, reopening after Co-op staff performed a complete inspection of the store and its products.

"Obviously our biggest concern is the safety of our customers and our shoppers. It didn't seem like it was a big issue, but if even one got into one our shoppers' baskets, we wanted to make sure we got it back," said spokesman Deane Collinson. "That is why we wanted to alert the media."

Earlier, the supermarket chain issued a voluntary recall of bulk bakery products, bulk food items and packaged cheeses purchased at the Oakridge location since Jan. 15 because of fears they might contain pins.

Customers who purchased those items during that period were asked to return them to the store for a full refund.

The store said there have been no reports of any injuries.

with files from CBC