Fungicides and the Effects of Mycotoxins on Milling Fractions of Irrigated Rice Giniani Carla Dors,* ,† Sergiane Souza Caldas, ‡ Helen Cristina dos Santos Hackbart, † Ednei Gilberto Primel, ‡ Carlos Alberto Alves Fagundes, § and Eliana Badiale-Furlong † † Laborató rio de Ciê ncias de Alimentos, Escola de Química e Alimentos, Universidade Federal do Rio Grande (FURG), Rua Eng. Alfredo Huch, 475, CP 474, Centro, Rio Grande, RS, ZIP 96201-900, Brazil ‡ Laborató rio de Ana ́ lises de Compostos Orgâ nicos e Metais, Universidade Federal do Rio Grande (FURG), Avenida Ita ́ lia, km 8, Campus Carreiros, ZIP 96208-410, Rio Grande, RS, Brazil § Instituto Riograndense do Arroz (IRGA), Avenida Bonifa ́ cio Carvalho Bernardes, 1494, ZIP 94930-030, Cachoeirinha, RS, Brazil ABSTRACT: This study aimed to evaluate the effect of fungicides on rice cultivation, regarding the occurrence and the distribution of mycotoxins in fractions of the processed grain, by a validated chromatographic method. A method based on extraction with acetonitrile:water, determination by HPLC-DAD, and confirmation by LC-MS was validated before the mycotoxin evaluation. Control samples and samples to which triazole fungicides had been applied were collected from experimental fields for four years. Results showed that 87% of the samples were contaminated with deoxynivalenol or zearalenone, and that all samples treated with fungicide were contaminated with some of these mycotoxins. Aflatoxin B 1 and ochratoxin A were found in 37% of the samples; half of them had been treated with fungicide. Therefore, fungicides tend to be stressors for toxigenic fungi found in the fields. KEYWORDS: aflatoxins, deoxynivalenol, ochratoxin, zearalenone ■ INTRODUCTION Around 15-20% of rice grains are lost due to cultural practices and processes, variety resistance, climatic conditions, and other variables that lead to fungal contamination. 1-3 Rice crops can be damaged by fungal diseases, such as blast, brown spot, and dark spot from contamination with Pyricularia oryzae, Bipolaris oryzae, Cercospora janseana, and other species that attack the plant in the field and decrease its productivity. In cultivated areas, preventive measures, such as the use of fungicides, are adopted, because fungi restrict the productivity and the health of the plants. 4 Both fungicides strobilurin and triazole are recommended for irrigated rice production to prevent loss caused by diseases, but the toxigenic fungal species might be selective and the damage they cause may not be related to productivity. Every toxigenic fungal species responds differently to fungicides, because it depends on the weather, the distribution of the active ingredient in plant tissues, the development of the plant, and the resistance of the cultivar. 4,5 These factors may be stressors in the production of mycotoxins. Fungicide formulations in emulsifiable concentrate (EC) or dispersed oil (DO) can increase penetration through the cuticle. Tebuconazole, an organic fungicide of the triazole group often applied to grain cultures, has systemic action that interrupts the functions of the cell membrane. Inhibition of sterol biosynthesis affects the synthesis of the cell membrane, hindering fungal metabolism. 6 Stressing factors trigger mycotoxin production by toxigenic fungal species, such as Fusarium graminearum, which con- taminate crops in the field. 5-7 Studies have shown that the mycota identified in rice has toxigenic species that can produce mycotoxins in different and complex conditions. 7,8 Researchers have found that rice bran (17.5%) and parboiled rice (15%) are the processed rice products which are more contaminated with mycotoxins that characterize contamination in the field, such as deoxynivalenol and zearalenone, and in storage, such as aflatoxin B 1 and ochratoxin A . 9-11 Rice contamination by mycotoxins might be caused by many environmental conditions, plant resistance, and toxigenic potential of the mycota, but preventive measures, such as adequate handling with the use of active ingredients which do not lead to the selection of toxigenic fungal species and promotion of their toxigenic potential, are very important to food safety. 12 The study of the effect of the fungicide on the mycotoxin occurrence is frequently carried out by isolating the toxigenic species and studying its response in vitro or in greenhouses, even though these conditions do not always reflect the conditions found in the field. 13 Monitoring mycotoxins in rice to ensure the safety of this raw material, widely used as food, is fundamental. Determining mycotoxins requires much care regarding the physical and chemical characteristics of these compounds and their random occurrence in trace amounts. Furthermore, compounds of the same family with small structural differences, but distinct toxigenic potential, must also be determined separately. 14 Liquid chromatography is a technique applied to routine analysis in many areas, including food; the use of different detectors enables the identification and quantitation of Received: July 23, 2012 Revised: January 18, 2013 Accepted: January 23, 2013 Published: January 23, 2013 Article pubs.acs.org/JAFC © 2013 American Chemical Society 1985 dx.doi.org/10.1021/jf305144t | J. Agric. Food Chem. 2013, 61, 1985-1990