The death toll from an outbreak of listeria in the United States has reached at least 13 people. The Centers for Disease Control says 72 infections have been reported in 18 states. The outbreak is linked to tainted cantaloupes from the Denver-based company, Jensen Farms. The Center for Science in the Public Interest, an advocacy group, says the outbreak reinforces the need for regulations to bar pathogens from produce. Melons are said to have caused 36 outbreaks of food-borne disease since 1990.