TRENTON — Romaine lettuce has returned to the menu in many places but the Center for Disease Control (CDC) advises that if you don't know where it was grown, not to eat it.

The CDC last week said it has narrowed the source of romaine lettuce tainted with E. Coli to product grown in the Central Coastal growing area of California but continued its investigation as no common grower, supplier, distributor, or brand of romaine lettuce has been identified. More product is also labeled with its harvest location, according to the CDC.

The New Jersey Department of Agriculture said that romaine grown in New Jersey can be "purchased with confidence."

The number of confirmed cases nationwide has grown to 52 nationwide, with 11 cases in New Jersey. Nineteen people have been hospitalized, including two people who developed hemolytic uremic syndrome, a type of kidney failure. No deaths have been reported.

The state Department of Health said the cases in New Jersey are four from Bergen and one each from Morris, Ocean, Sussex, Union, Mercer, Essex and Hudson counties.

The CDC said the illnesses started between Oct. 5 and Nov. 18.

E. coli, or Escherichia coli, is a bacteria that normally lives harmlessly in the intestines. Some types can cause illness through exposure to contaminated food or water, or contact with animals or other people. Symptoms include severe stomach cramps, often bloody diarrhea, and vomiting.

Symptoms develop usually within two to eight days of ingesting the germ.

E. coli can be prevented by thorough hand washing after using the bathroom or changing a diaper, before and after food preparation, and after contact with animals.

The CDC said the current outbreak is not related to one earlier this year. The first outbreak was traced to the Yuma, Arizona, where 90 percent of all the romaine lettuce grown in the United States between November and March.

Contact reporter Dan Alexander at Dan.Alexander@townsquaremedia.com or via Twitter @DanAlexanderNJ