NY -- Standard&Poor's CreditWire 12/10/1998 -- Standard&Poor's today assigned its preliminary double-'B'/single-'B'-plus senior unsecured/subordinated debt rating to Canandaigua Brands, Inc.'s $400 million Rule 415 mixed shelf registration. The new registration is an add-on to an existing $300 million registration, bringing the total available under Canandaigua's shelf registration to $700 million. At the same time, Standard&Poor's affirmed Canandaigua's double-'B' corporate credit rating and single-'B'-plus subordinated debt rating. The ratings outlook is stable. About $195 million of rated debt is outstanding. Ratings reflect Canandaigua's strong cash generation from a diverse portfolio of beverage alcohol products, offset, in part, by the company's acquisitive growth strategy in recent years and the competitive nature of its markets. The Fairport,