go bad
     v 1: stop operating or functioning; "The engine finally went";
          "The car died on the road"; "The bus we travelled in
          broke down on the way to town"; "The coffee maker
          broke"; "The engine failed on the way to town"; "her
          eyesight went after the accident" [syn: {fail}, {give
          way}, {die}, {give out}, {conk out}, {go}, {break}, {break
          down}]
     2: become unfit for consumption or use; "the meat must be eaten
        before it spoils" [syn: {spoil}]
Source: WordNet® 2.0