Raleigh, N.C. — The number of salmonella cases could get worse before it gets better, Dr. Jeffrey Engel, the state epidemiologist, said Friday.

A salmonella strain known as Saintpaul has sickened 23 people in North Carolina and more than 1,200 people in 42 states.

Officials are still trying to pinpoint the source of the strain.

Joe Reardon, director of the state Food and Drug Protection Division, told The Associated Press on Friday that testing found the salmonella strain oranienburg at Charlotte-area food supplier El Campo Produce Inc.

Reardon said the strain has been found in North Carolina and Texas and linked to the Texas supplier Grande Produce. He said it could be in other states, too.

State officials on Thursday announced a recall of jalapeno peppers and Hass avocados distributed in North Carolina after they said two positive salmonella tests at El Campo.

Officials have requested that Grande Produce, of Hidalgo, Texas, recall all the implicated products distributed in North Carolina.

“It may be contamination of distribution plants. It may be contamination within shipping trucks. All these things are under investigation,” Engel said, adding that a major part of the investigation is focused on Grande Produce.

The U.S. Food and Drug Administration lifted its salmonella warning on tomatoes Thursday. Federal health advisers warned that people most at risk from salmonella – including the elderly and people with weak immune systems – should avoid fresh jalapenos and serranos and any dishes that may contain them, such as fresh salsa.

“This may not be tomatoes, but it may be food associated with tomatoes that are cross-contaminating,” Engel said.

Engel said that while numbers will probably rise, he anticipates they will fall off if officials locate the source of the contamination.

“We might not be able to say this is over until August or September,” Engel said.

Agriculture and Consumer Services Department spokesman Brian Long said El Campo Produce Inc. distributed to about 100 restaurants and a few small markets in 25 counties, including Durham and Lee.

The Food and Drug Protection Division and state Division of Environmental Health staff are working to determine how many North Carolina food distributors, restaurants, grocery stores and other food-sellers received the produce.

Engel said products determined to be contaminated have been pulled off shelves.

The Hass avocados were shipped from Texas in boxes labeled “Frutas Finas de Tancitaro Hass Avocados, Produce of Mexico,” 60 count, with lot number HUE08160090889. The jalapenos were shipped in black, plastic crates weighing about 15 pounds and containing no brand name or other label.

One week ago, health investigators converged on a Charlotte-area restaurant suspected of being a source of multiple salmonella illnesses. State food protection experts took 42 samples from the restaurant, including a variety of vegetables, fruits and spices.

Salmonella illnesses are common; North Carolina has about 1,500 cases each year. But those usually come from raw eggs, undercooked chicken or simple errors such as a child drinking out of a dog bowl – not a single-source contamination like what has spread nationwide in recent months.