An expanded warning on peppers—this time including serranos from Mexico—has been issued by the Food and Drug Administration after it was discovered that both a sample of a pepper and a sample of irrigation water collected on a farm in the state of Nuevo Leon, Mexico contain Salmonella Saintpaul with the same genetic fingerprint as the bacteria that is causing an outbreak that has sickened more than 1,300 people across the country.

As a result, until further notice, the FDA is advising consumers to avoid both raw serrano peppers and raw jalapeño peppers if they were grown, harvested or packed in Mexico, as well as any foods that contain them. Serranos and jalapeños grown in the U.S. are not connected to the outbreak, nor are  commercially canned, pickled or cooked jalapeno peppers.

The latest finding comes after months of tracking the source of the outbreak that was originally thought to have been caused by tomatoes. While tomatoes have not been cleared as a cause, the FDA has indicated that tomatoes now on the market are safe to eat. The Centers for Disease Control and Prevention says on its Web site that, although it's unusual, it appears likely that "more than one food vehicle is involved in this outbreak."

Last week we reported that Salmonella Saintpaul had been traced back to a jalapeño pepper that had been provided by someone who was ill. That discovery was the first time the strain of Salmonella Saintpaul had been linked to a piece of produce and caused the investigators to turn to peppers grown in Mexico.

The investigation continues and the FDA is working with state regulatory agencies and food industry groups representing restaurants, grocery stores and wholesalers to make sure that their new advisory is clearly understood.

We'll continue to report on developments in the case and both the FDA and the CDC are issuing daily updates on their Web sites. This graphic shows how the FDA has been tracking the suspected food items.