The former head of Edmonton's health authority will lead an investigation into last year's deadly nationwide listeriosis outbreak, Prime Minister Stephen Harper announced Tuesday.

Sheila Weatherill, a past CEO of Capital Health in Edmonton, was appointed by Harper to act as an independent investigator into the outbreak, which sparked a recall of Maple Leaf Foods meat products across Canada.

She will also offer recommendations on how to prevent a similar outbreak in the future, although she won't provide recommendations as to criminal or civil liability.

"Protecting the health of Canadian families and the safety of the Canadian food supply is of paramount importance to our government," Harper said in a news release issued Tuesday.

Weatherill's report is due to Agriculture Minister Gerry Ritz by July 20 — four months later than the government's original plan to have the report finished in March. The investigation will be kept private until the report has been submitted.

At the height of the crisis in September, Harper promised an arm's-length investigation would be launched at the end of the deadly outbreak, which left 20 Canadians dead.

The prime minister said at the time that the purpose of the probe would be to ensure "we get to the bottom on the government's side, on the bureaucratic side, of exactly what transpired and to make sure that as we go forward and we make changes to our system, that this kind of thing can't happen again."

Harper, however, stopped short of promising a full judicial inquiry, which would have allowed Weatherill to call witnesses and compel testimony.

Maple Leaf pledges co-operation

The outbreak, which began in August, was traced back to meat slicing equipment at a Maple Leaf Foods plant in Toronto and prompted the company to issue a recall of virtually all the products produced at the facility.

A total of 191 products from the Toronto plant were recalled during the crisis, costing Maple Leaf an estimated $20 million. The company also agreed last month to pay up to $27 million to settle class-action lawsuits.

Maple Leaf Foods president and chief executive Michael McCain said Tuesday the company welcomed Harper's announcement and would co-operate fully, "sharing our key learnings from this past fall."

"We are confident that the joint efforts by government and industry, and the consistent application of high standards, will further enhance the Canadian food safety system and the integrity of our food," McCain said in a statement released on the company's website.

Others, however, criticized the Conservatives for not launching a full judicial inquiry into the outbreak.

Weatherill "will get information based on the goodwill of the participants who may or may not tell her the full story," said Bob Kingston, president of the Agriculture Union, which represents meat inspectors through the Public Service Alliance of Canada.

The union wants the government to undertake a parliamentary review of the outbreak and Canada's food-safety system.

Investigation 'too limited': Liberal critic

Opposition MP and Liberal agriculture critic Wayne Easter called Tuesday for a full judicial inquiry.

"Canadians deserve the truth," Easter said. "Ms. Weatherill's resources and powers are too limited to reveal what actually happened."

The Conservatives have already taken heat from the Canadian Medical Association Journal, which has slammed the long-pending investigation for being inferior to those that probed Canada's tainted blood scandal if the 1980s, the Walkerton tainted water crisis in 2000 and the 2003 SARS epidemic.

In an editorial published in September, the CMAJ said that under the investigation's terms of reference, the investigator would not have the power to subpoena witnesses or documents, the investigation would not be public, and there would be no commitment to publishing the findings or reporting to Parliament.

Weatherill, who is a member of the Order of Canada and was named to Harper's advisory committee on the public service in 2006, will be paid between $1,200 and $1,400 a day plus travel and living expenses to serve as an investigator.

She lost her job as president of Edmonton's Capital Health last July as part of the provincial Conservative government's decision to integrate separate health regions into one super board.

With files from the Canadian Press