Canadian food group Maple Leaf Foods has found a number of positive test results for listeria at the company's Bartor Road facility.

The facility was closed on 20 August due to the finding of a consistent inoculation in products manufactured at the site that were linked to an outbreak of listeriosis.

The outbreak resulted in the death of at least 17 people and resulted in the recall of 191 Maple Leaf products sold across Canada.

The plant reopened on 17 September after the Canadian Food Inspection Agency agreed to allow Maple Leaf to resume production on a limited trial basis.

The CFIA has been testing each batch before allowing any products to go on sale and, as part of these tests, has discovered what Maple Leaf described as a "small number of positive tests for listeria".

"To date, over 5,000 product tests have been completed, with only four positive findings for Listeria monocytogenes," Maple Leaf said. "These four positive findings were in two products produced on a single line, and not related to the prior incident. No products from the plant, including the four product samples that tested positive, have been distributed for public consumption, and the protocols in place have proven to be very effective."

"Listeria exists in all food plants, all supermarkets and presumably in all kitchens", said Michael McCain, Maple Leaf's president and CEO. "Our testing protocols are designed to find positive results so we can remediate them immediately. The Bartor Road team has found a very small number of positive results, not unexpectedly, and is reacting exactly according to food safety protocols. While there is no risk to the public, we are behaving in the most conservative way possible, according to the protocols in how these findings are always to be handled."

McCain added: "We are being ultra cautious in this facility, more cautious than any other plant in North America. Under the circumstances, we consider this to be an appropriate action plan. Listeriosis is an exceptionally rare illness, but we are taking every precaution possible."