A whey product has been formulated for use as a lactic starter medium. Phosphate-treated whey medium (PWM) has been shown to support growth of lactic cultures and prevent phage proliferation. Comparisons were made of a commercial phage inhibitory medium (PIM), reconstituted non-fat dry milk (NDM) and PWM. PWM inhibited all phages tested and stimulated starter growth. PWM was not as stimulating as PIM but was better than NDM. Good Cheddar cheese has been made using PWM. PWM is more economical than PIM but NDM is the most economical one if cheese yield is considered.