Delivery trucks were parked this week outside the Montreal offices of Amira Enterprises, which imports and supplies nuts and dried fruit to the Canadian market. CBC

The Quebec company at the centre of a walnut recall says none of its products has tested positive for E. coli despite widespread warnings from health officials.

The Canadian Food Inspection Agency told consumers earlier this week to avoid eating all bulk and pre-packaged raw, shelled walnuts from Amira Enterprises, a Montreal-based fruit and nut distribution company.

One person in Quebec has died and 13 other Canadians have fallen sick with E. coli bacterial infection. Federal health officials believe many of them ate walnuts before they got sick.

The officials confirmed, however, that they have not found the bacterium on any walnuts from Amira or any other company.

'There has been no detection of E. coli in walnuts' — Mark Raizenne, Public Health Agency of Canada

Amira president Adel Boulos said his company is nevertheless co-operating with the investigation and has pulled its products from shelves across Ontario, Quebec and Atlantic Canada.

"The conclusion is Amira products tested negative for E. coli," Boulos told CBC News.

"We did the recall because we did not want anybody to get sick. Now, the government is still investigating this so there could be another source. Nothing is confirmed yet."

Bacteria hard to detect on walnuts

Since January, 14 cases of E. coli infection with the same genetic fingerprint have been reported in Canada.

Nine of the cases have been in Quebec. Two have been confirmed in Ontario along with two in New Brunswick. The location of the 14th case is not known.

A Quebec Health Ministry spokesperson said Thursday that the Quebec person who died had pre-existing health problems.

'The detection of E. coli on a dry surface like a walnut is expected to be negative most of the time.'— Mark Raizenne, Public Health Agency of Canada

Another Canadian has developed hemolytic uremic syndrome (HUS), an illness associated with E. coli infections that can result in kidney failure.

Of the 14 reported cases, nine people consumed walnuts and seven of them ate them from the same distributor, said Mark Raizenne, director general of the Public Health Agency of Canada's centre for foodborne, environmental and zoonotic infectious diseases in Ottawa.

Still, "there has been no detection of E. coli in walnuts," Raizenne said.

"Currently, the CFIA is doing a very intensive food investigation in terms of determining the contamination of walnut products from multiple distributors."

However just because no E. coli has been detected doesn't mean the walnuts haven't been contaminated, Raizenne said.

"The detection of E. coli on a dry surface like a walnut is expected to be negative most of the time unless the contamination is extremely high," he said.

Infection from E. coli can cause serious and potentially life-threatening illnesses. Symptoms include severe abdominal pain and bloody diarrhea.

Company gets walnuts from U.S.

Amira Enterprises said the walnuts were imported from the U.S.

The Health Canada warning includes walnuts under the Amira, Tia and Merit Selection brands.

The recall notice also mentions Mistral Mix containing walnuts, and Salad Booster with walnuts, which are sold under the brand names Amira and Tia.

All package sizes — including walnut halves and crumb packs — all lot codes and all best-before dates are affected.

Until further notice, the public health agency says consumers who have raw shelled walnuts in their home can reduce the risk of E. coli infection by roasting the walnuts before eating them.

Consumers should place the nuts on a cooking sheet and bake them in a 180 C (350 F) oven for 10 minutes, turning the nuts over once after five minutes.

With files from The Canadian Press