a1 Senior Scientist, Department of Food Science, Agricultural Research Organization, The Volcani Center, PO Box 6, 50250 Bet Dagan, Israel.
Panels of 40 to 60 “non-expert” consumers attempted to distinguish between the taste of organically and conventionally grown fruits and vegetables. Wherever possible, samples of the two types of produce were obtained by picking them in the growing orchards/fields to avoid any question of authenticity, and cold-stored without treatment under the same conditions, for periods reflecting their shipping time to markets. Some physical, chemical, and instrumental analytical tests were also performed. No consistent preference pattern emerged. For grapefruit, grapes, carrots, spinach, sweet corn and tomatoes, the differences in hedonic ratings and scores between the two types of produce were not significant. For mangoes and orange juice, the conventional type was preferred, while the reverse was true for bananas; in each of these three instances the result could be ascribed to fruit being tasted closer to its optimum maturity.
Screening tests were performed to detect any traces, at the parts-per-billion level, of chlorinated hydrocarbons and organophosphorus compounds used as pesticides, or their degradation products. No traces were detected in any of the samples examined (bananas, grapes, carrots, spinach, sweet corn or tomatoes), whether organically or conventionally grown. In those samples examined (bananas, grapes, carrots, spinach, sweet corn and tomatoes) by quantitative tests for the three major fertilizer elements used conventionally (NPK), nitrogen and phosphorus concentrations were not consistently greater, while potassium concentrations were either equal or greater, than in the organically grown samples. Among the anion analyses performed on orange juice, grapefruit juice, carrots, spinach and tomatoes, nitrates and particularly nitrites either were not detected, or occurred at negligible concentrations in all samples. Phosphates were found at higher concentrations, but not significantly so, in four of the five organic products tested; no phosphates were detected in either type of tomatoes.