Correctional Service Canada says inmates at the Saskatchewan Penitentiary are getting enough food after claims a deadly riot may have been triggered by a dispute over portion sizes.

Jason Leonard Bird, 43, was stabbed to death and two inmates were seriously injured when up to 200 prisoners rioted on Wednesday.

The confrontation began around 1 p.m. CST, following lunch, when inmates would normally be heading back to their cells.

Dispute over food portions

James Bloomfield, regional president with the Union of Canadian Correctional Officers, said the deadly riot may have been triggered by a simmering dispute over food portions.

Jason Leonard Bird, 43, died at Saskatchewan Penitentiary in Prince Albert. (Holly Lynn/Facebook)

He said there was trouble brewing in the kitchen in the days leading up to the riot.

Corrections Canada said on Friday it could not discuss the cause of the riot while its investigation was ongoing.

But the service said in an email that inmates were being adequately fed.

"Serving sizes are in accordance with Canada's Food Guide," the email said.

"The regular meal plan is adequate for all federally-sentenced offenders under our jurisdiction and is based on a menu that is standardized across the country."

John Hutton, executive director of the John Howard Society of Manitoba, said on Friday he was aware of concerns about changes to the way the canteen operates at prisons including the Saskatchewan Penitentiary.

He said the food services for the canteen had been privatized and "one of the concerns is that the prices have gone up in the canteen and there may be some issues around availability."

Hutton added that inmates sometimes purchase canteen food to supplement their meals.

Corrections denies canteen change

But Corrections Canada said there were no changes to the canteen at the Saskatchewan facility, adding that inmates were responsible for setting prices and tracking losses and profits.

It said a B.C. company called Prototype Integrated Solutions Inc. sold items such as clothing and televisions to inmates, but it did not sell items at canteens.

Corrections Canada did not respond directly when asked if it had received any complaints about food or portion sizes in the lead up to the riot.

It said it had a system in place to provide timely and impartial solutions to inmates' grievances.