WASHINGTON, July 5 (UPI) -- Investigators are looking at all the ingredients in fresh salsa as they try to find the cause of the U.S. salmonella outbreak, officials said Saturday.

Tomatoes and jalapeno peppers are still suspect, the Atlanta Journal & Constitution reported. But the Centers for Disease Control said the investigation has widened.

"We're still looking at tomatoes as a possible cause, along with jalapenos and cilantro and other ingredients in fresh salsa," said CDC spokesman Glenn Nowak.

At least 943 cases of salmonella have been reported in 40 states, the U.S. Food and Drug Administration reported Saturday. When the outbreak began in April, it was blamed on tomatoes, and many restaurant chains took them off the menu.

Nowak said investigators were looking at restaurants where at least two people have become sick within 10 days.

"We're working through the holiday weekend and we're hoping we can have something early in the week, more information in terms of what the case controls studies show," he said.