Want pico de gallo on your fajita taco? You just might have to settle for chopped onion. Jalapeño and serrano chiles, as well as cilantro, have been implicated in the multistate outbreak of salmonella infections. They join the list that began with tomatoes — and all are ingredients in the enormously popular Tex-Mex relish, pico de gallo. San Antonio’s hundreds of Tex-Mex restaurateurs are faced with some important decisions this week. Blanca Aldaco, owner of two local Aldaco restaurants, said she’s not serving pico de gallo at this time. “We’re only using our cooked salsa,” she said. Tomatoes, connected with...