Commercial milk and two brands of yogurt containing bifidobacteria were obtained from retail outlets. All products were evaluated for viability of bifidobacteria and lactic acid bacteria during refrigerated storage at 4 degrees C. Milk was evaluated at 9, 6, and 3 days prior and past its expiration date. The yogurts were evaluated at 3, 2, and 1 week prior and past their expiration. Viability of bifidobacteria and lactic acid bacteria in milk and yogurt remained above 10(6) CFU/ml or g until the expiration date of the respective products. This microbial concentration is the recommended minimum dose to receive the health benefits of these organisms.