WASHINGTON--(BUSINESS WIRE)--Marc Perrone, International President of the 1.3 million member United Food and Commercial Workers International Union (UFCW), sent a letter to Attorney General Eric Holder yesterday urging the U.S. Department of Justice to block the proposed merger between Comcast and Time Warner Cable because of the negative impact the resulting company will have on working families’ much-needed access to affordable and reliable cable and Internet services. Perrone wrote his lette