University of Minnesota researchers have discovered and received a patent for a naturally occurring lantibiotic — a peptide produced by a harmless bacteria — that could be added to food to kill harmful bacteria like salmonella, E. coli and listeria. The U of M lantibiotic is the first natural preservative found to kill gram-negative bacteria, typically the harmful kind. "It's aimed at protecting foods from a broad range of bugs that cause disease," said Dan O'Sullivan, a professor of food science and nutrition in the university's College of Food, Agricultural and Natural Resource Sciences. "Of the natural preservatives, it has...