Health officials say 16 people in the greater Calgary area have become sick from E. coli in recent weeks and investigators are working to nail down the source of the bacteria.

Alberta Health Services said Wednesday that four of the 16 people are or were hospitalized, but are recovering.

"In this particular outbreak that we are still investigating, there have been 16 lab-confirmed cases of E. coli 0157:H7," said Dr. Judy MacDonald, the region's medical health officer.

"This type of E. coli can be very serious."

E. coli O157:H7 can cause symptoms including nausea, vomiting, abdominal cramps and bloody diarrhea. In severe cases people may have seizures or strokes, suffer permanent kidney damage or die.

Those infected range in age from less than one year to 74 and became ill between Nov. 25 and Feb. 2.

Details of the illnesses came after the Canadian Food Inspection Agency announced a recall of some raw pork products in the region due to possible E. coli contamination.

The agency said the recall was triggered by an investigation into people getting sick, but no illnesses have been definitively linked to the products.

The recall involves pork produced by Hillview Meat Processor that was distributed to seven stores in Calgary. The products include raw fresh or frozen meat cuts, ground pork, sausages and ready-to-eat products.

The agency said consumers should not eat the products and has warned restaurants, retailers, distributors and manufacturers against using them.

MacDonald said none of the patients has developed hemolytic uremic syndrome, which is a severe complication that can arise from some E. coli infections.

Alberta Health Services is working with the CFIA on the investigation, she said.