Romaine Lettuce
A worker labors at a romaine lettuce farm outside San Luis, Ariz. The FDA recently found listeria bacteria on romaine lettuce from a farm in California. Reuters

After the cantaloupe-associated listeriosis outbreak linked to a Colorado farm that has left 15 people dead and 84 sick across 19 states, it is romaine lettuce now threatening to spread the infection in North America.

A random sample of romaine lettuce from True Leaf Farms of California taken by the U.S. Food and Drug Administration has tested positive for the bacteria.

The produce seller has already recalled about 30,000 pounds of chopped and bagged romaine lettuce in 90 cartons.

We are fully cooperating with the FDA, and we are contacting all of our customers to ensure prompt removal of any product potentially associated with the recall, said Steve Church, owner of True Leaf Farms. We are committed to conducting this recall quickly and efficiently to reduce any risk to public health.

The initial recalled product was shipped Sept. 12-13 to a retail food-service distributor in Oregon, which then distributed it to at least two additional states, Idaho and Washington .

True Leaf Farms also extended its recall notification to cover additional product shipped to wholesale food-service distributors in 19 other states, and Alberta, Canada.

To this point, no illness has been reported linked to this recalled product.

Listeria monocytogenes is a bacterium that can cause serious and sometimes fatal infections in young children, elderly people, and others with weak immune systems. Healthy individuals may suffer only short-term symptoms, such as high fever, headache, nausea, abdominal pain, and diarrhea. The infection also can cause miscarriages and stillbirths.