NY -- Standard&Poor's CreditWire 5/10/96 -- Standard&Poor's today has lowered the corporate credit rating of Rykoff-Sexton Inc. to double-`B'- minus from double-`B'-plus and the subordinated debt rating of the company to single-`B' from double-`B'-minus. Standard&Poor's has removed the ratings from CreditWatch, where they were placed Dec. 6, 1995. The CreditWatch placement followed the announcement of a proposed merger with Wilkes-Barre, Penn.-based U.S. Foodservice Inc., the fifth-largest broadline foodservice distributor in the U.S. The downgrades reflect the operating risk associated with integrating two firms of about equal size, high debt levels and capital spending, and limited financial flexibility over the near-term. The merger does provide greater geographic breadth and access to many major U.S. markets