Romaine lettuce possible source of E. coli outbreak

Officials in at least one region affected by an E. coli outbreak in Ontario are zeroing in on romaine lettuce.

There have been 24 confirmed cases of E. coli 0517:H7 in the Niagara, Halton, Guelph and Waterloo regions.

Laboratory testing has determined that cases in the four health units have the same DNA fingerprint.

Niagara Region's associate medical officer of health says their investigations have shown romaine lettuce to be the only thing ``significantly related" to their cases.

Doug Sider says most of the confirmed cases in the region were linked to two restaurants, but of the ones that weren't, the sick people had still eaten romaine lettuce.

Sider says the two restaurants do not share a supplier, so the Canadian Food Inspection Agency will be looking back further to see if there was a common point of distribution.