Fusarium and fumonisins in maize I in South America

TORRES A. M.; RAMIREZ M.L.; CHULZE S.N.

Mycotoxins in Food, Feed and Bioweapons.

Springer-Verlag

Lugar: Berlin; Año: 2010; p. 179 - 200

South America with its considerable north-south extent is subject to climates that vary from tropical, subtropical, warm temperate to temperate. This situation makes the area favourable for production of a wide range of agricultural products including cereals, oily seeds, beans, fruits, nuts. Maize (Zea mays L.) is one of the world major cereal grain with the world?s annual average production (2004-2006) of 678 million metric tons (Mt), representing 32 % from the 2.15 billion metric tons of the world cereal grain production. South America produces 64 mmt, 10% o the world maize production.. This cereal is the staple food source for humans and also the feed source for domesticated animals. The end ?use products can be foods, such us  breakfast cereals, indigenous foods as tortillas, tamales, tacos, enchiladas, porridge, snack foods, feeds, in the world 67% of the maize production is intended for animal feed, or industrial uses depending the regions and their cultural preferences. Also several countries base their economies on this cereal marketing the main exporting nations are USA (53%), China (19%), and Argentina (17%) (Chung et al., 2007) Both situations the climatic conditions and the amount of production in South America can be favourable for fungal contamination and mycotoxin occurrence. Maize can be infected with several fungal species, potential mycotoxin producers. Among these species, Fusarium verticillioides (Sacc.) Nirenberg and Fusarium proliferatum (Matsushima) Nirenberg are relevant since can infect maize worldwide and produce fumonisins. Fumonisin B1 is the best known and studied of the fumonisins, but other derivatives are known to occur naturally as well (Plattner et al., 1996, Sewram et al., 2005). Dietary exposure to fumonisins cause adverse effects in farm and laboratory animals,  these toxins have been associated with leukoencephalomalacia en horses (Ross et al., 1992)  pulmonary edema syndrome in pigs (Harrison et al., 1990) and liver and kidney toxicity in rats (Voss et., al 1988)  and apoptosis in many types of cells (Jones et al., 2001). Fumonisins are phytotoxic but their role in plant diseases caused by F. verticillioides if any, has not been clearly defined (Lamprecht et al., 1994). Epidemiological studies showed some evidence between intake of fumonisins and oesophageal cancer in Africa, Brazil, China, and Italy. Also fumonisin B1 reduce the folate uptake in cell lines, and fumonisin intake has been related with neural tube defects (Marasas et al, 2004).    Since mycotoxins are unavoidable contaminants in food and feed chains their presence need to be reduced in order to avoid their effects to human and animal health and to diminish the annual market loss through rejected maize. Previous reports on the situation of mycotoxins in South America considering the period (1995-2000) and (2000-2004) showed that the major problems appeared to be fumonisins in maize and maize products (Chulze, 2004, Rodriguez Amaya and Sabino 2002) . The impact of mycotoxins in South America is significant from the point of view of: a.- The effects on public health. The staple diet of the population sometimes is based on a commodity like maize which is susceptible to contamination with more than one mycotoxin, for example fumonisins and aflatoxins. The level of contamination of the agricultural products and by-products is sometimes of great concern, and taken into account the consumption of the contaminated food by the population, the daily intake of mycotoxins could be sometimes higher than the maximum tolerable daily intake established by Joint FAO/WHO Expert Committee on Food Additives (JECFA)  (FAO/WHO, 2001). In some countries, other factors as under-nourishment could have synergic effects to mycotoxins. Occurrence of fumonisins has been shown in maize -based infant foods in Brazil, being this situation of high risk for the infant population. Using a biomarker approach, exposure to fumonisins at individual level was determined in populations from Brazil and Argentina. A ratio SA/SO higher than 1 was found in urine samples of two populations, one from the North of Argentina with high consumption of maize-based foods prepared from home growing maize and, another from South Brazil, an area with a diet mainly based on maize products called ?polenteros? and with high incidence of esophageal cancer (Solfrizzo et al., 2004)