"The FDA believes it was critically important to have a "clean break" in the romaine supply available to consumers in the U.S. in order to purge the market of potentially contaminated romaine lettuce related to the current outbreak", the statement said.
The U.S. Food and Drug administration on Monday gave the all clear to consume romaine lettuce from Arizona, Florida, Mexico and California's Imperial Valley.
Investigators have been tracing back the romaine eaten by people sickened in the outbreak.
The leafy greens industry also launched a task force after the deadly Yuma outbreak a year ago, an effort that resulted in some significant changes to growing practices, including a greater distance required between greens growing fields and animal livestock operations. Retailers are also being asked to discontinue selling romaine lettuce, which is why shoppers no longer see it on store shelves.
No common grower, supplier, distributor or brand of romaine lettuce has been identified in the outbreak.
"Over the Thanksgiving holiday, the FDA continued to investigate the outbreak", according to a statement from FDA Commissioner Dr. Scott Gottlieb. Hydroponic lettuce and lettuce grown in greenhouses also do not appear to be affected by the outbreak.
The FDA, along with Centers for Disease Control and Prevention, warned US residents last week not to consume the lettuce from anywhere because of an E. coli outbreak.
As of Monday, the FDA said 43 people became ill in 12 states due to the outbreak, and another 22 people were sickened in Canada.
The FDA and industry leaders, scrambling to respond to yet another E. coli outbreak tied to romaine lettuce, have agreed to a deal to give consumers more information about where their lettuce is from. It noted the labels are voluntary, and that it will monitor whether to expand the measure to other leafy greens and produce.
"Romaine as a category has had a year that's been unfortunate", Whitaker said.
The CDC announced on November 20 that any and all romaine lettuce products in the USA should be thrown away due to the risk. An industry group said people can expect to start seeing labels as early as this week. Children under 5, adults older than 65 and people with weakened immune systems, such as people with chronic diseases, are more likely to develop severe illness, but even healthy children and adults can become seriously ill. As no contaminated product has been found in the marketplace and the source of the contamination has not been identified, there have been no product recalls in Canada or the U.S associated with this outbreak.
The CDC and the FDA now say that you should avoid romaine lettuce from the Central Coast regions of northern and central California.
Food poisoning outbreaks from leafy greens are not unusual. Since romaine has a shelf life of about 21 days, health officials said last week they believed contaminated romaine could still be on the market or in people's homes.