From February 1986 to January 1988, samples of several processed Florida citrus juice products--frozen concentrated orange juice, orange juice from concentrate, pasteurized orange juice, grapefruit juice, and grapefruit juice from concentrate--were surveyed regularly during production. Samples were assayed for sodium, potassium, ascorbic acid, thiamin, calcium, iron, folic acid, phosphorus, magnesium, zinc, and copper primarily for the purpose of nutrition labeling. Means, standard deviations of the means, and maximum and minimum values of each nutrient are expressed in mg/6 fl oz for each product. In addition, the estimated percentage of the U.S. Recommended Daily Allowance (U.S. RDA) for each nutrient claimable at time of packing is given. (To be claimed on a nutrition label, a nutrient must occur at a minimum level of 2% of the U.S. RDA per serving, according to U.S. Food and Drug Administration [FDA] regulations.) The estimated percentage of the U.S. RDA claimable for ascorbic acid ranged from 90% to 100% in the orange juice products and was 70% for the grapefruit juice products. These juices are all considered significant sources of vitamin C. In the orange juice products, the percentage of the U.S. RDA for thiamin ranged from 6% to 8% and was 8% for folic acid. Significantly smaller amounts of each vitamin were noted in the grapefruit juices. Small but claimable levels of magnesium, calcium, copper, and phosphorus were found in one or more of the products tested. Neither zinc nor iron was found at the U.S. RDA minimum level of 2%. Significant amounts of potassium, for which there is no established U.S. RDA, were found in all the citrus juice products.(ABSTRACT TRUNCATED AT 250 WORDS)