The front page of today’s Daily News mixes politics and produce with an odd sticker advertising Christine Quinn’s appearance tomorrow at the ribbon cutting for Fairway’s new store in Kips Bay. Last month Quinn picked up the endorsement of a grocery workers’ union; perhaps she’ll soon be debating Republican contender John Catsimatidis, the owner of Gristedes, on the merits of arugula versus iceberg lettuce. Of course, the more significant backing picked up by Quinn recently came from the Retail, Wholesale and Department Store Union. Other, more powerful labor groups — including the UFT — are still up for grabs, but if Quinn’s Democratic opponents don’t pick off a few soon, they’re going to have serious trouble in September’s primary.