Food safety and nutritional quality of organic vegetables

The growing awareness of the importance of the health and the environment led public interest increasingly focusing on the problem of quality of foods. Considerable attention is being paid to organic farming. Organic products of plant origin are known to be grown without the aid of chemical-synthetic pesticides and without the use of readily soluble mineral fertilisers or sewage sludge and waste compost. Crop rotation and extensive soil tillage are stated in every guideline of organic farming associations and in EC Regulation on organic farming (2092/91). Numerous studies confirm that many people believe that organic foods are healthier than conventionally produced foods, but up to now it is not still clear if agriculture techniques really affect nutrient composition, while it is widely assumed that any benefit derived from organic foods is due to the absence of pesticide residues. Actually, it is very difficult to give a final answer, especially because of the large amount of variability in agricultural data resulting from uncontrollable factors, such as rainfall and sunlight, which influence nutrient content. To resume data, it is worthwhile underlining a recurring trend to a higher average Vitamin C content in organic vegetables (especially tomatoes, lettuce, spinach and cabbage). Mineral content has not the same regular trend, but there appears to be higher amounts of some nutritionally significant mineral in organic, compared to conventional crops. In particular, Phosphorous and Magnesium have been found higher in potatoes, carrots, lettuce, spinach, and cabbage. These data could be explained with the differences in soil nutrition, which affects plant metabolism and mineral absorption from soil; they are also in agreement with the lower nitrate content found in the same plants.