WASHINGTON — Government inspectors documented unsanitary conditions at several Boar’s Head deli meat plants, not just the factory that was shut down last year after a deadly outbreak of listeria poisoning, federal records show. Newly released reports from Boar’s Head plants in New Castle, Indiana; Forrest City, Arkansas; and Petersburg, Virginia, described multiple instances of meat and fat residue left on equipment and walls, dripping condensation falling on food, mold, insects and other problems dating back roughly six years.