TORONTO - Ontario's top doctor has issued an public alert concerning two E. coli cases thought to be linked to iceberg lettuce distributed in the province.

Dr. David Williams issued the warning in a release Friday night saying two E. coli cases in the Chatham-Kent area are linked to the same strain identified in 38 cases in the U.S.

All of the cases are thought to come from shredded iceberg lettuce distributed by Aunt Mid's Produce Company.

The release says the lettuce, which is distributed in five pound industrial bags, may have been used at institutions such as hospitals and long-term care homes, as well as restaurants in southwestern Ontario.

Mark Nesbitt of the province's ministry of health and long-term care says the public alert is meant to notify health units to be aware that people may have eaten the affected product.

The lettuce was last distributed in Ontario on Sept. 26 and because the product has a 12-day shelf-life, it could still be in use.

"We want our public health units to be aware that the product has been out there and it may have been consumed in hospitals, long-term care homes and some restaurants," said Nesbitt.

"We want people to be aware that it is out there on everyone to be on alert."

Public health units in southwestern Ontario are contacting specific restaurants that may have received the product and asking them to place it on hold, the release added.

The Ministry of Health and Long-Term Care is working with the Canadian Food Inspection Agency on the investigation.

Symptoms of E. coli include diarrhea, vomiting, and dehydration.

On Thursday, the head of the Windsor Regional Hospital criticized the food inspection agency for failing to notify the institution when the strain was identified.

The agency notified the provincial Health Ministry and local health unit this week that contaminated lettuce from Michigan may have turned up at the hospital's Met campus.

The U.S. outbreak was confirmed on Sept. 26, but hospital president David Musyj said he wasn't notified by the CFIA until Wednesday.

Changes need to be made, Musyj added.

Similar calls for changes to the agency followed a listeriosis outbreak which is now blamed for 20 deaths across Canada.