OTTAWA -- Prime Minister Stephen Harper won't cut loose his embattled agriculture minister despite Gerry Ritz's "tasteless" jokes last month about a listeriosis outbreak linked to processed meats that has now killed 17 people.

Harper said Thursday he is standing by Ritz, who apologized after The Canadian Press reported he was cracking wise about the crisis during an Aug. 30 conference call with scientists, bureaucrats and political staff.

The controversy is embarrassing to Ritz, Harper acknowledged, but doesn't merit him losing his job after all his hard work on the listeriosis outbreak, linked to meats produced by Maple Leaf Foods.

"Back in the summer and for many, many weeks, I happen to know that Minister Ritz was working very hard on this," Harper said.

"I think the story is obviously very embarrassing for him, but should not detract from the good work that he has done, to get on top and understand this matter, to improve the system and to communicate publicly with Canadians and ensure government officials are all doing their jobs."

During the call, Ritz called the crisis "a death by a thousand cuts -- or should I say cold cuts."

And when told about a new death in Prince Edward Island: "Please tell me it's (Liberal agriculture critic) Wayne Easter."

Both Liberal Leader Stephane Dion and NDP Leader Jack Layton have urged Harper to fire Ritz, which the prime minister said Thursday he would not do.

"He's been doing a good job on this file and I applaud him for apologizing completely and forthrightly."

Staff from the Prime Minister's office were in on the call when Ritz made the comments, Dion said.

"And yet they allowed him to continue in his role as the government spokesman for this crisis. Why?"

Dion was campaigning in Toronto and NDP Leader Jack Layton was in Winnipeg, while Bloc Quebecois Leader Gilles Duceppe was to meet with supporters in Carleton-Sur-Mer, Que., and Green Leader Elizabeth May campaigned in Nova Scotia.

So far, Harper has demonstrated an aggressive, merciless attitude toward campaign-trail gaffes and missteps, apologizing quickly and without reservation.

When the Tories introduced an online ad that depicted a puffin pooping on Dion's shoulder, Harper wasted no time in acknowledging the ad was in poor taste and issuing an apology.

The same thing happened in the wake of a war-room email that tried to impugn the motives of Jim Davis, the outspoken father of Cpl. Paul Davis, who was killed in Afghanistan in 2006.

Campaign tactician Ryan Sparrow, who responded to Davis's criticism of the decision to pull Canadians out of Afghanistan in 2011 by describing him as a Liberal supporter, was booted from the Tory war room and ordered to apologize.

This time, however, a Conservative spokesman has already indicated Ritz won't face disciplinary action.

"It was clearly inappropriate," Kory Teneycke said Wednesday. "It was intended as a joke, but some things are not appropriate to joke about."

And later: "A resignation was not offered and none was asked for."

That wasn't sitting well with Dion.

"Why does Mr. Harper think that it's okay to fire a campaign staffer for an inappropriate comment about a dead soldier's father, but he can ignore an even more offensive remark by one of his senior ministers?" the Liberal leader asked.

"Why are communications staffers held to a higher standard than his cabinet ministers?"

During the call, Ritz was deeply concerned about the political fallout as listeriosis claimed more victims in the days before the federal election call, according to sources who were listening in.

Others on the call included communications staff from the Prime Minister's Office, most of Ritz's staff, Health Minister Tony Clement's policy and communications advisers, and senior public servants, including deputy health minister Morris Rosenberg.

Officials from the Canadian Food Inspection Agency provided updates on the disease during the conversation.

The sources who spoke to The Canadian Press did so on condition of anonymity. Harper's Conservative government has been relentless, on a number of occasions in the past, in searching for and punishing anyone thought to have provided embarrassing information to reporters.

But as the Tory damage-control effort swung into action Wednesday, it was Ritz who offered apologies for his ill-chosen words -- three times.

He first expressed regrets in an email, then repeated them in person at a campaign rally in suburban Ottawa. He then apologized yet again, outside his parliamentary office building at 10:30 p.m. for the benefit of television cameras that had missed him earlier in the evening.

"It was a highly stressful time," Ritz said in his original prepared statement.

"Many people were working countless hours and attending countless meetings to keep on top of the situation. In that context, I made a couple of spur-of-moment offhand comments. In particular, one about my official opposition critic, whom I have already called to apologize.

"My comments were tasteless and completely inappropriate. I apologize unreservedly."

Ritz later added some remarks directly addressed to those who suffered personal losses in the listeriosis outbreak.

"I want to offer my most humble and heartfelt regrets to the families of those affected by this tragedy," he said. "I did not intend to add to their suffering, and I very deeply apologize for that."

The words failed to satisfy Layton, who called on Harper to take disciplinary action.

"I think the prime minister has to fire Gerry Ritz as minister immediately, and he has to fire him as a candidate in this election," Layton said.

"I don't see anything funny about what Mr. Ritz said."

Easter brushed off Ritz's reference to him, saying he doesn't take it as a literal wish to see him dead. The more important point, he said, is that Ritz showed insensitivity to the families of those affected.

"I'm very much more concerned about how it sounds and how it would be hurtful to those who've lost loved ones," said Easter. "I think that's the real issue here."

Easter noted that he's already called for Ritz's resignation -- and continues to do so -- because of his broader role in shaping Tory food inspection policies.

"That's a much bigger issue and goes to the heart of the matter. A minister should not be joking about that issue. This is very, very serious."

Earlier Wednesday, Ritz had little to say when asked about his conference-call comments as his flight from Saskatoon touched down at the Ottawa airport.

A bearded man with the minister jostled with journalists as Ritz beelined through the terminal to a waiting sedan. At one point the man grabbed a reporter's recorder and jabbed at the off button.

For two minutes Ritz stared dead ahead as he was peppered with questions about the conference call. His only words were clipped.

"Not right now, guys," he said.

Then: "Get out of my face, please."

After his speech at the rally Wednesday night, Ritz would not take questions and was whisked from the premises by aides. He reappeared a few hours later to repeat his apology for a new batch of cameras but again refused to answer questions.

Listeria can cause listeriosis, a foodborne illness that causes high fever, headache, neck stiffness and nausea that is of particular concern to the elderly, pregnant women and the infirm.

So far, 17 deaths have been linked to the recall of food products from a Maple Leaf Foods plant in Toronto. There have been 14 deaths in Ontario, and one each in British Columbia, Alberta and New Brunswick.

The conversation on Aug. 30 began with talk of the mounting death toll and trends in the spread of the disease.

Sources say Ritz began the call by asking: "Are there any more bombs out there?" -- implying any politically damaging news.

10:53ET 18-09-08