The Canadian Food Inspection Agency has expanded a cheese recall at a farm in Salmon Arm, B.C., that has killed one person and made about a dozen others sick.

The CFIA and Gort’s Gouda Cheese Farm are warning the public not to consume the Mild Gouda Cheese because it is contaminated with E. coli bacteria.

The cheese was sold in various sizes, bearing a red ‘Raw’ sticker at certain retail stores in British Columbia and through Internet sales from May 27 to September 14.

The CFIA says that lot codes 122 to 138 are affected by the recall.

Kathy Wikkerink, the co-owner of Gort’s Cheese Farm, says they are desperately trying to figure out how E. coli contaminated the raw cheese produced at their farm.

"We are so sorry and we are trying to get to the source of the E. coli, but we don't know the source and we don't know what happened," Wikkerink said on Thursday.

Officials with B.C.’s Interior Health Authority say that an elderly woman who ate contaminated cheese died from the bacteria.

Three people in B.C. and eight in Alberta have been reported sick from eating the cheese, but the Public Health Agency of Canada stresses that there could be more cases.

Five Calgarians are included among the people made sick by the bacteria.

Dr. James Talbot, Alberta's Chief Medical Officer of Health, says that the cases are relatively mild, but stresses that E. coli poisoning is very serious.

"It's relatively rare but it's not, in this case. This outbreak is nine cases overall right now and one of them died. That's a fairly high mortality rate for most E. Coli but we do have outbreaks where it seems that the organism is more likely to produce the toxin and then the mortality rate can be higher," he said on Thursday.

Officials say that cheese contaminated with E. coli may not look or smell spoiled, but eating food contaminated with these bacteria may cause serious and potentially life-threatening illness.

Gort’s Gouda Cheese Farm began voluntarily recalling products earlier this week after E. coli was connected with 14 products.

Anyone who has bought the product recently is advised to throw it away immediately.

(With files from the Canadian Press)