Maple Leaf Foods president Michael McCain says it was no surprise to learn that Listeria bacteria was found at his company's Toronto plant as it can never be eliminated.

"While this plant has undergone intensive sanitization, we will never eliminate (the Listeria bacteria)," he told a Thursday news conference in Toronto.

"It exists in all food plants, all supermarkets and presumably all kitchens."

He made the statement in the wake of news that more contaminated meat samples have been found at the Toronto plant at the centre of a massive listeriosis outbreak.

The outbreak -- which left 20 people dead across the country -- had prompted the plant's temporary shutdown, the recall of thousands of tainted products.

Four tainted meat products were found at the Maple Leaf Foods plant on Bartor Road, the company and the Canadian Food Inspection Agency announced late Wednesday.

The facility reopened on Sept. 17. The four positive samples were found in 2,700 products that were tested on Sept. 29 and 30.  The strain found in the most recent tests is the same as the one identified in August, but on a different production line.

"We tested, we identified a positive, we quarantined the product, and it never left our control," McCain. "The stringent food safety program that we have in place is working. There was zero risk to the public in this event."

CFIA and Maple Leaf officials are investigating the findings, he said.

'Exceptionally low'

But having four positive samples out of 3,850 "is exceptionally low," McCain said. "That said, it's our job to reduce the risk to an even lower number and ensure the product never leaves our plant."

That is standard procedure for the company and the industry at food processing plants across the country, he said.

Mansell Griffiths, a food safety expert, said, "These test results are within the limits or even much better than the limits you would expect at any other meat producing plant."

During the outbreak that occurred in August, McCain said the bacterium was found "in large amounts, across multiple product lines, multiple products, in high doses, and was linked to illness."

However, "What occurred two months ago is not what's happening today," he said.

"What's happened yesterday is routine - no risk to the Canadian public, happens every day in the Canadian food industry."

Food safety means risk can be reduced to the lowest level possible, but not eliminated, McCain said, adding finding Listeria bacterium can be like finding a needle in a haystack.

Listeria, while dangerous to a small segment of the Canadian public, is benign to the masses, he said.

McCain said Maple Leaf Foods will accept any amount of risk reduction deemed necessary, provided the same standards apply to his competitors and imported food products.

The Bartor plant hasn't shipped food products to the public yet, but McCain said that is related more to mechanical problems and not food safety issues.

The equipment is being sanitized six to eight hours per day, he said.

Some consumers interviewed by CTV Toronto, however, said they wouldn't be consuming Maple Leaf processed meat products again any time soon.

With a report from CTV Toronto's Zuraidah Alman