Scientists in Southern California are asking the kind of questions that make soda drinkers uneasy after a recent study that found fast-food soda fountains were serving up high levels of bacteria along with self-serve drinks. Researchers from Loma Linda University found bacteria levels that surpassed U.S. Environmental Protection Agency regulations for drinking water at fast-food restaurants in the eastern Coachella Valley, where largely low-income, Latino farmworker families have struggled with accessing potable water. Communities in the desert region about two-and-a-half hours east of Los Angeles have experienced water pollution identified by federal officials. Water sampled in local fast-food restaurants had bacteria such as E. coli, salmonella and Pseudomonas aeruginosa that can cause severe illness.