Prime Minister Stephen Harper is promising an independent investigation into the deadly nation-wide listeriosis outbreak which is being blamed for 13 deaths.

The latest confirmed death is that of Frances Clark, an elderly woman who lived in Madoc, Ont.

Harper says he is "troubled" by the outbreak, and that an investigation will aim to ensure a similar outbreak does not happen again.

Harper was in Windsor, Ont. announcing millions of dollars in funding over the next five years towards the national auto innovation fund, which will help reopen a Ford plant in Windsor.

Meanwhile, pre-sliced mushrooms from the Fresh Obsessions Brand have been added to the listeriosis recall list today by the Canadian Food Inspection Agency (CFIA).

The produce in question came from Ravine Mushroom Farms in Woodbridge.

Health officials have linked the outbreak to processed meat products from a Maple Leaf Foods plant in North York and more than 240 deli meat products have been recalled.

For a complete list of products recalled in the listeriosis outbreak, visit the Canadian Food Inspection Agency website.

With files from The Canadian Press.