Following a dangerous outbreak of E. coli traced to romaine lettuce that sickened 32 people across 11 states, major leafy-greens producers agreed to label their packed romaine by region or state and by harvest date. The change will happen “immediately,” said six of the largest growers in a letter sent to the FDA on Nov. 25. All romaine lettuce in the U.S. was pulled from store shelves Nov. 20 in a recall led by the FDA and all consumers, restaurants, and other institutions advised to get rid of any romaine on hand. The FDA made this move in an abundance of caution as the origin of the contaminated lettuce wasn’t known and remains unknown. In a voluntary agreement, companies told the FDA they would mark lettuce sold bagged or in mixes, and would provide details to retailers who sell loose leaves and whole romaine heads, and to restaurants that purchase it wholesale. The labeling will start with lettuce harvested starting November 23. Products will say, “Romaine grown in [source] and harvest after [date],” the growers said. It will include all locations for lettuces combined from multiple sources. Harvesting is just beginning in Yuma, Arizona, on the Mexican broder, and in Florida...