ORIGINAL PAPER The effect of three organic pre-harvest treatments on Swiss chard (Beta vulgaris L. var. cycla L.) quality Nancy Daiss Æ M. Gloria Lobo Æ Ana R. Socorro Æ Ulrich Bru ¨ ckner Æ Joachim Heller Æ Monica Gonzalez Received: 7 August 2006 / Revised: 4 December 2006 / Accepted: 6 December 2006 / Published online: 10 January 2007 Ó Springer-Verlag 2006 Abstract Despite the increasing interest in organic products, our understanding of how different organic treatments affect fruit and vegetable quality is still limited. The effect of three organic pre-harvest treat- ments [effective microorganisms (EM), a fermented mixture of effective microorganisms with organic matter (EM-Bokashi + EM), and an auxiliary soil product (Greengold Ò )] on Swiss chard quality was evaluated. The Swiss chard was analyzed 8 and 19 weeks after sowing. The treatments did not notably modify the physical and chemical quality of the chard when compared with control plants. Chard harvested 19 weeks after sowing showed greater differences in nutritional quality than chard harvested 8 weeks after sowing. Control plants had higher water content than the plants treated with EM, EM-Bokashi + EM and Greengold Ò . Chards treated with EM-Bokashi + EM had lower ascorbic acid content and higher phosphor and magnesium content than control plants. Applica- tion of EM to plants induced higher levels of calcium compared with non-treated plants. Keywords Organic production Á Effective microorganisms Á Bokashi Á Greengold Ò Á Physical and chemical quality Á Nutritional quality Á Swiss chard Introduction In multiple epidemiological studies eating vegetables has been found to protect against several chronic dis- eases associated with aging such as cardiovascular diseases and some types of cancer [1]. Swiss chard (Beta vulgaris L. var. cycla L.) is a leafy vegetable highly valued because it is available year round and for the nutritional properties of its leaves which contain considerable amounts of vitamin C, potassium, calcium and magnesium [2–4]. In the recent years, the growing consumer’s aware- ness of health and safe-controlled foods, together with environmental protection plans, have determined a significantly increased interest in organic food [5, 6]. Horticultural crops produced organically should behave differently than those produced with chemical fertilizers, pesticides and herbicides. Exposure to dif- ferent chemicals, nutrients and cultivation techniques will probably affect the physiological response of the product. However, there is a relative scarcity of pub- lished research about the effect of organic production on quality of vegetables [7]. Woese et al. [8] presented a review of the literature of comparative studies between organically and conventionally produced foods. However, most of the reviewed material refers to nitrate contents, pesticide residues and other phys- ico-chemical indexes and there is a lack of information N. Daiss Á M. G. Lobo Á A. R. Socorro Á M. Gonzalez (&) Instituto Canario de Investigaciones Agrarias, Apdo. 60., 38200 La Laguna, Spain e-mail: mgonzal@icia.es U. Bru ¨ ckner Research Center Geisenheim, Section of Soil Fertility, Von-Lade-Strasse 1, Geisenheim, Germany J. Heller Fachhochschule Wiesbaden, Standort Geisenheim, Von-Lade-Strasse 1, Geisenheim, Germany 123 Eur Food Res Technol (2008) 226:345–353 DOI 10.1007/s00217-006-0543-2