(June 3, UPDATED 4:00 p.m.) The Centers for Disease Control and Prevention is focusing on roma and large, round tomatoes in its investigation of an outbreak of Salmonella Saintpaul that has sickened at least 40 people in New Mexico and Texas.

The CDC said in a news release that the specific variety and the origin of tomatoes are still under investigation, but that “preliminary data suggest that large tomatoes, including roma and red round, are the source.”

Emily Palmer, a spokeswoman for the Texas Department of State Health Services, said consumers in Texas and New Mexico are being advised not to eat raw roma or full-sized round tomatoes other than those sold on the vine or grown at home.

Palmer said 21 illnesses had been reported in Texas as of June 3. She said there have been several hospitalizations but no reported deaths in that state.

Deborah Busemeyer, communications director for the New Mexico Department of Health, said that 19 people in that state have suffered Salmonella Saintpaul infections with the same genetic fingerprint as those in Texas. She said the state agency is investigating 17 other Salmonella Saintpaul cases that could be related.

Busemeyer said June 3 that there had been at least 12 people hospitalized in New Mexico. No deaths have been reported.

Meanwhile, 30 other cases of Salmonella Saintpaul have been reported in Arizona, Colorado, Idaho, Illinois, Indiana and Kansas. The CDC, the Food and Drug Administration and state agencies are investigating whether tomatoes are linked to those illnesses.

The CDC said illnesses were reported from April 23 to May 27.

The first illnesses in New Mexico were reported May 6 and have been linked to tomatoes purchased at Wal-Mart, Basha’s Supermarkets and Lowe’s Markets, Busemeyer said.

“We bought a ton of tomatoes, and we’re in the process of testing them,” she said. “We’re testing all different kinds. We tried to take a wide sample.”

Tomatoes have had issues with salmonella before. State and county officials linked tomatoes to a salmonella outbreak that sickened 19 customers and three employees in October 2007 at a Quiznos sandwich shop in Rochester, Minn. In 2006, tomatoes were linked to an outbreak of Salmonella Newport that affected 109 people in 19 states.

Last year growers in Florida persuaded state legislators to institute a mandatory safety program to help prevent such outbreaks.