By Keith Coffman DENVER (Reuters) – A Colorado task force charged with tightening controls on marijuana edibles unveiled proposed rules on Friday to limit potency levels, require clearer labeling and assure that children cannot get their hands on pot-infused confections. Under the guidelines released by the Colorado Department of Revenue, serving sizes of edible pot products would be restricted to 10 mg of THC, the psychoactive component in marijuana, down from 100 mg. Packaging would also have to alert consumers the items contain cannabis.