(Portland, OR)  --  A food-cart worker, who's accused of dealing heroin behind the business, is in custody.  Portland police say 40-year-old Christopher Bartz was arrested Tuesday near the Satay Indonesian food cart at Southwest 9th and Alder.  Authorities say a confidential informant told police that Bartz dealt heroin directly behind the business.  Bartz is to make his next court appearance on November 28th.