The U.S. Food and Drug Administration (FDA) is testing cilantro, jalapeno peppers, and Serrano peppers, as well as tomatoes and imported products, to find the source of the salmonella epidemic that is responsible for making sick at least 943 people in 40 states and Washington, D.C, according to the numbers reported by the Center for Disease Control and Prevention (CDC).

After weeks of warning consumers to keep away from the most usual fresh tomatoes, the FDA and CDCP officials now say it is premature to declare tomatoes are to blame or that jalapeños are the lead suspect. Consequently, they still list it with tomatoes, cilantro and serrano peppers as one of the common salsa ingredients under investigation. About 1,700 tomatoes have been tested, and none has turned out to contain the Salmonella Saintpaul bacterium implicated in the outbreak.

According to FDA spokeswoman Stephanie Kwisnek, officials stepped up cilantro and serrano peppers testing, but "there is no specific 'prime suspect'."

Meanwhile, as the number of people falling ill tops the thousand, if federal officials leading the investigation wait too long for proof, there is a risk that more people will get sick.

Officials in New Mexico, the first state to identify the outbreak, as well as Chicago health officials, where roughly 50 cases had been reported, saw a strong connection to fresh salsa, including homemade salsa. Later, CDC, New Mexico and Texas -- which also had some of the earliest cases -- officials decided the evidence pointed to tomatoes as the most likely suspect.