LOS ANGELES — Tomatoes are making a comeback in most of the United States, though the source of the salmonella outbreak that has sickened at least 383 people remains a mystery.

LOS ANGELES — Tomatoes are making a comeback in most of the United States, though the source of the salmonella outbreak that has sickened at least 383 people remains a mystery.

McDonald's Corp. said Wednesday that it would reintroduce sliced tomatoes in its U.S. restau-rants over the next seven to 10 days, and some markets in the Los Angeles area, including Vons and Fresh & Easy, have begun stocking produce sections with Roma, plum and red-round tomatoes grown in areas deemed safe by the Food and Drug Administration.

Yum! Brands Inc., which owns the KFC, Pizza Hut and Taco Bell chains, said it started resupplying its restaurants on Monday.

Fresh salsa is reappearing at El Pollo Loco Inc. outlets, which a spokeswoman said had begun accepting shipments of FDA-approved tomatoes Friday night.

Some consumers were happy the fruit was back; others were nervous about its return.

"I'm going to wait a week before I buy tomatoes," said Juan Negrete, 53, a security guard from Los Angeles, as he ordered lunch at a McDonald's.

"I usually eat a salad once or twice a day, but now I'm scared."

The Centers for Disease Control and Prevention raised the number of victims by 106 on Wednesday, citing a recent surge in reports from several states.

But the dates of outbreak haven't changed: The first person fell ill April 10 and the last, so far as officials know, on June 5. A total of 48 people have been hospitalized.

"We have to say that the outbreak is ongoing," Robert Tauxe, the CDC's deputy director of the Division of Foodborne, Bacterial and Mycotic Diseases, said on a conference call Wednesday. "It's really too early to call the peak. We certainly cannot say it's over."

The search for the source is continuing, with officials focusing on parts of Mexico and southern and central Florida. The FDA has ruled out crops in 39 other states, along with several counties in northern Florida and the District of Columbia.

"We may not ultimately know the farm where these (tainted tomatoes) came from," said David Acheson, the FDA's associate commissioner for foods, in an interview. "Personally, I'm optimistic, but I'm trying to be realistic."