.S. inflation picked up a bit last month as food costs rose, though overall inflation remained mostly tame.

Consumer prices increased 2.4% in May compared with a year ago, according to a Labor Department report released Wednesday. That is up from a 2.3% yearly increase in April. Excluding the volatile food and energy categories, core prices rose 2.8% for the third straight month. Economists pay close attention to core prices because they generally provide a better sense of where inflation is headed.