The centres for disease control in the US are warning customers to stay away from all form of romaine lettuce, as the scope of an E coli investigation grows. The original outbreak which made more than 50 people sick across 16 states, seemed to focus on chopped romaine lettuce grown in Arizona. But an update on Friday, says customers should also avoid whole heads and hearts of romaine, in addition to chopped lettuce. So far, no single grower, brand or distributor has been implicated in the outbreak. So far, there’s no word of any recalls in Canada.