Calgary’s Oakridge Co-op had to take several drastic – and costly – measures over a two-month period last year as a result of food tampering incidents, manager Al Madsen testified on Thursday.

Madsen said from the first discovery of food products with pins and nails in them, on Jan. 18, 2010, until a suspect, Tatyana Granada (right), was arrested on March 16, 2010, about a dozen surveillance cameras were installed to go along with the two or three cameras in place in January.

He said some cameras were installed with the knowledge of staff after the January incidents and several more strategically located cameras were "installed surreptitiously after staff left," following further tampering incidents on Feb. 17.

Madsen said the cost of the new cameras was between $35,000 and $40,000.

He told Crown prosecutor Martha O’Connor at Granada’s trial that the store was closed at least twice to conduct entire grid searches for tampered products.

Madsen said the pattern of tampering was consistent through January, where pins and nails were placed in fresh foods in the cheese, deli, bakery and produce sections. Still, the Co-op and police were stymied.

Madsen said undercover security officers were hired to be on the lookout at all times for possible tampering by customers or staff.

Following yet another rash of discoveries of food items with pins in them on March 11, 2010, the manager said it was decided not to close the store again, but to have cashiers inform all customers at checkouts to be vigilant about checking any food products for tampering.

That day, the bulk food bins were dumped out and because the store could not ensure safety of customers, $9,000 worth of food was thrown out.

It was around that time that assistant manager Chris Goode identified Granada as having been barred from the Co-op stores in December 2009 for shoplifting.

Madsen said he reviewed video surveillance of Granada’s entire shopping trip from March 10, 2010, and outlined her route and where she stopped.

Granada, 44, is on trial for three counts of mischief causing property damage and five counts of trespassing, for entering Oakridge Co-op. She has pleaded not guilty to all charges.

Madsen said no further tampered products have been found since Granada’s arrest.