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Maize, mycotoxins and the poor

Maize, mycotoxins and the poor. Outline. Mycotoxins and maize Mycotoxins (fumonisin) effects on health Cancer HIV Stunting NTD Reduction strategies Denying the benefits. Fusarium. F. verticilloides F. proliferatum. Fumonisin B1 Fumonisin B2 Fumonisin B3. Fumonisin B1

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Maize, mycotoxins and the poor

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  1. Maize, mycotoxins and the poor

  2. Outline • Mycotoxins and maize • Mycotoxins (fumonisin) effects on health • Cancer • HIV • Stunting • NTD • Reduction strategies • Denying the benefits

  3. Fusarium F. verticilloides F. proliferatum Fumonisin B1 Fumonisin B2 Fumonisin B3 Fumonisin B1 Fumonisin B2 Fumonisin B3 Mycotoxins are one of the major problems of maize cultivation Mycotoxins are produced by two genera of fungi Aspergillus A. flavus A. parasiticus Aflatoxin B1 Aflatoxin B2 Aflatoxin B1 Aflatoxin B2 Aflatoxin G1 Aflatoxin G2 Slide by Katia Petroni, University of Milan, IT

  4. Fungi can infect maize seeds from pre-harvest to post-harvest storage Fungi grow under high humidity and warm temperatures. They produce mycotoxins under the terminal water stress prior to harvest wounding by pests facilitates Fusarium, but not Aspergillus infection European corn borer larva in a maize stalk Slide by Katia Petroni, University of Milan, IT

  5. Infection by Aspergillus Infection by Fusarium

  6. Major mycotoxins and their effects • Fumonisin B1, B2 and B3 are • 1. Carcinogenic (liver, kidney, esophagus) • Teratogenic (neural tube defects) • Stunting agents • Aflatoxin B1 and G1 are • Mutagenic (chromosomal aberrations) • Carcinogenic (liver, kidney) Aflatoxin B1 Fumonisin B1 Aflatoxin is a known human carcinogen Strict contamination limits apply

  7. Total annual HCC cases attributable to aflatoxin worldwide: 25,200–155,000 Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide, with prevalence 16–32 times higher in developing countries than in developed countries. Aflatoxin is a known human liver carcinogen. Liu and Wu (2010) Environmental Health Perspectives Global Burden of Aflatoxin-Induced Hepatocellular Carcinoma: A Risk Assessment. Environ Health Perspect. 118:818-824. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2898859/pdf/ehp-118-818.pdf

  8. Research also demonstrated an association between exposure and impairment of child growth (1-3). Evidence of acute toxicity and immunomodulation in people and animals has also been described (4). Schoolchildren in the Eastern Cape region of South Africa, through the Primary Schools Nutrition Programme, were provided with peanut butter as a nutritional supplement that allegedly contained high amounts of aflatoxin 5). 1) Gong YY et al., (2002) Br. Med. J. 325:20. 2) Gong YY et al., (2004) Environ. Health Perspect. 112:1334. 3) Turner PC et al., (2007) Int. J. Epidemiol. 36:1119. 4) Williams JH et al., (2004) Am. J. Clin. Nutr. 80:1106. 5) South African Medical Research Council, “Aflatoxin in peanut butter” http://www.mrc.ac.za/promec/afloxin.htm

  9. http://www.ars.usda.gov/is/pr/2007/070426.htm

  10. Reasonable limits for aflatoxins? Economic considerations Various EU countries had different contamination levels allowed for Aflatoxin New limits have been introduced in 2001. They are expected to reduce health risks by approximately 1.4 European deaths per billion population per year. Maximum allowable aflatoxin levels in Europe (pre-2001) and Africa (ppb)

  11. New limits in force in EU from 2001 The new EU limits for aflatoxins, tougher than international standards, will cause a loss of $670 million in exports to Europe for grains with ridiculous benefits for consumers.

  12. Fumonisin: pieces of the puzzle • Fumonisin inhibits sfingolipid biosynthesis •  Effect on folate (vitamin B6) uptake • Affects embryo development • Association between fumonisin consumption and illnesses (e.g. leukoencephalomalacia in horses and oesophageal cancer in humans) • Estimates of human exposure • Association between fumonisin and NTD in humans • Stunting • HIV transmission The effects on the central nervous system (encephalomalacia in horses and, in experimental conditions, also in turkey and rabbit) and carcinogenic activity (kidney and liver tumors in rat) seem both linked to the interference with sfingolipid biosynthesis

  13. Loss of Sphingomyelin means a reduced amount of folate transporter and folate uptake Sphingomyelin is required for GPI-anchored proteins Folate transporter Fumonisins inhibit sphingolipid biosynthesis Reduces the formation of sphingomyelin Marasas et al. (2004)

  14. Folate deficiency and cancer Stevens and Tang (1997) Fumonisin B1-induced sphingolipid depletion inhibits vitamin uptake via the glycosylphosphatidylinositol-anchored folate receptor. J Biol Chem. 272:18020-5. Liu and Ward (2010) Folate and one-carbon metabolism and its impact on aberrant DNA methylation in cancer. Adv Genet. 71:79-121. Fumonisin reduces folate uptake. Reduced folate means more cancer. Ames BN (2001) DNA damage from micronutrient deficiencies is likely to be a major cause of cancer. Mutat Res. 475:7-20. A deficiency of any of the micronutrients: folic acid, Vitamin B12, Vitamin B6 [folate], niacin, Vitamin C, Vitamin E, iron, or zinc, mimics radiation in damaging DNA by causing single- and double-strand breaks, oxidative lesions, or both. Folate deficiency causes extensive incorporation of uracil into human DNA (4 million/cell), leading to chromosomal breaks. This mechanism is the likely cause of the increased colon cancer risk associated with low folate intake. Some evidence, and mechanistic considerations, suggest that Vitamin B12 (14% US elderly) and B6 (10% of US) deficiencies also cause high uracil and chromosome breaks.

  15. Presence of F. moniliforme in good and moldy corn produced in regions of high or low incidence of esophageal cancer All values significant at P<0.01 From the available evidence it is reasonable to conclude that fumonisin is responsible for a significan fraction of esophageal cancer, particularly in developing countries (Rheeder et al., 1992)

  16. HIV and hepatocellular and esophageal carcinomas related to consumption of mycotoxin-prone foods in sub-Saharan Africa Williams et al (2010) Am. J. Clin. Nutr. 92:154-60. doi: 10.3945/ajcn.2009.28761 As far as the HIV epidemic is concerned, food and nutritional factors have not received that same attention from a transmission perspective. Mycotoxin contaminants in foods may also be important in the HIV epidemic, for instance, chronic aflatoxicosis is associated with immune suppression and a reduction in essential nutrients and may result in deficiencies known to promote HIV progression.

  17. Fig. 1. Per capita consumption of 4 mycotoxin-prone foods in sub-Saharan African countries in 1993. *Denotes median country for maize consumption. ##Denotes 2004 President’s Emergency Plan for AIDS Relief country. The consumption rates of maize, cassava, rice, and peanuts varied significantly across nations, providing varied levels of potential risk to aflatoxins and fumonisins.

  18. HIV and esophageal cancer deaths were significantly related to maize. Hepatocellular cancer deaths were positively related to rice but negatively related to maize consumption. %Muslim was positively correlated with rice consumption, but inversely with maize consumption Conclusions: HIV transmission frequency is positively associated with maize consumption in Africa. The relation between cancer and food suggests that fumonisin contamination rather than aflatoxin is the mostly likely factor in maize-promoting HIV. Williams et al (2010)

  19. The most likely mechanism is that fumonisin might increase membrane permeability, which could promote HIV transmission. Alternatively, fumonisin may promote HIV infections by interfering with the biosynthesis of ceramide and complex sphingolipids, which are implicated in the membrane properties and in the attachment of HIV to human cells. However, the available evidence indicates that fumonisins result in less infective virions. Because some 1.7 million new infections are estimated to occur annually in SSA, the model predicts that addressing the cause of the HIV-maize relation may prevent up to one million new infections annually. Williams et al (2010)

  20. Fumonisin exposure through maize in complementary foods is inversely associated with linear growth of infants in Tanzania Kimanya et al. (2010)Mol. Nutr. Food Res. 2010, 54, 1659–1667 Children who consumed complementary food with fumonisins concentrations 42 μg/kg body weight were on average 1.3 cm shorter and 328 g lighter at 12 months. The effect on weight was mediated by length loss.

  21. Quetzaltenango has a mostly indigenous population that consumes high amounts of maize as their staple food   Incidence of neural tube defects (NTD per 10,000 live births) General U.S. popul.: <3 Quetzaltenango: 106 US Mean incidence and range in incidence of various locations within the regions or countries are shown; the bar for Limpopo represents one data point. In Italy the incidence of spina bifida is 3.3/10,000 in the 1992-1999 period. Total NTDs: 6.8 Marasas et al. (2004)

  22. Examples of suspected fumonisin-associated birth defects: anencephaly, spina bifida and encephalocele. All are from one summer in one hospital in Guatemala. Photos courtesy of Dr Julio Cabrera (from Parrott, 2010). Parrott W (2010) Genetically modified myths and realities. New Biotechnol. 27:545-51.

  23. Spina bifida (a common form of NTD) Spina bifida (Latin: "split spine") is a developmental birth defect caused by the incomplete closure of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open. If the opening is large enough, this allows a portion of the spinal cord to protrude through the opening in the bones. There may or may not be a fluid-filled sac surrounding the spinal cord. Other neural tube defects include anencephaly, a condition in which the portion of the neural tube which will become the cerebrum does not close, and encephalocele, which results when other parts of the brain remain unfused. http://en.wikipedia.org/wiki/Spina_bifida Spina bifida http://www.scienceclarified.com/images/uesc_02_img0090.jpg

  24. anencephaly encephalocele http://commons.wikimedia.org/wiki/File:Spina_bifida_side.jpg http://neuropathology.neoucom.edu/chapter11/images11/11-2al.jpg

  25. Folic acid and NTD The incidence of spina bifida can be decreased by up to 75% when daily folic acid supplements are taken prior to conception Istituto Superiore di Sanità (2006) National register of rare diseases: congenital malformation and folic acid. Edited by A. Pierini, F. Bianchi, P. Salerno and D. Taruscio; iv, 114 p. Rapporti ISTISAN 06/34 (in Italian). Available at www.iss.it .

  26. REFERENCES: folate supplementation and NTD Laurence et al. (1981) Double-blind randomised controlled trial of folate treatment before conception to prevent recurrence of neural-tube defects. Br Med J (Clin Res Ed) 282:1509-11. MRC Vitamin Study Research Group. (1991) Prevention of neural tube defects: results of the Medical Research Council Vitamin Study. MRC Vitamin Study Research Group. The Lancet 20.338:131-7. Kirke et al. (1992) A randomised trial of low dose folic acid to prevent neural tube defects. The Irish Vitamin Study Group. Arch Dis Child 67:1442-6. Czeizel et al. (1994) Pregnancy outcomes in a randomised controlled trial of periconceptional multivitamin supplementation. Final report. Arch Gynecol Obstet 255:131-9. Smithells et al. (1983) Further experience of vitamin supplementation for prevention of neural tube defect recurrences. The Lancet 1(8332):1027-31. Mulinare et al. (1988) Periconceptional use of multivitamins and the occurrence of neural tube defects. JAMA 260:3141-5. Milunsky et al. (1989) Multivitamin/folic acid supplementation in early pregnancy reduces the prevalence of neural tube defects. JAMA 24;262(20):2847-52. Bower et al. (1989) Dietary folate as a risk factor for neural-tube defects: evidence from a casecontrol study in western Australia. Med J Aust 150:613. Werler et al. (1993) Periconceptional folic acid exposure and risk of occurrent neural tube defects. JAMA 269:1257-61.

  27. Embryos after 24 h in culture medium mother injected with 20 mg/kg body weight FB1 on d 7.5 and 8.5 50 µmol/L FB1 none Embryos after 24 h in medium d 17.5 50 µmol/L FB1 Exposing pregnant mice or embryos to fumonisin causes NTDs normal fetus 50 µmol/L FB1 plus 1 µmol/L folinic acid Administration of folate or a complex sphingolipid is preventive Marasas et al. (2004) Fumonisins Disrupt Sphingolipid Metabolism, Folate Transport, and Neural Tube Development in Embryo Culture and In Vivo: A Potential Risk Factor for Human Neural Tube Defects among Populations Consuming Fumonisin-Contaminated Maize. J. Nutr. 134:711-6.

  28. Guatemala has one of the highest NTDs incidences in the world. • The population with the highest risk for NTD are the highlands indigenous of Guatemala Torres et al., (2007) Estimated Fumonisin Exposure in Guatemala Is Greatest in Consumers of Lowland Maize. J. Nutr. 137:2723-2729. Background Fumonisin B1 is a known liver and kidney carcinogen in rodents. There is a growing body of evidence that suggests that fumonisin B1 is possibly carcinogenic to humans. The daily per-capita maize consumption in Guatemala was 318 g … urban maize consumption was 102 g/d and rural maize consumption was 454 g/d. NTD occur at a much higher frequency in countries where maize consumption is high and fumonisin contamination is likely. A provisional maximum tolerable daily intake (PMTDI) of 2 µg·kg body weight-1·d-1 for fumonisins B1, B2, and B3, alone or in combination, has been proposed.

  29. Preliminary calculated estimate of the fumonisin (FB) exposure in women eating nixtamalized maize products (102–454 g/d) made from maize sold in local markets from 20 Departments Values much greater than the suggested PMTDI of 2 µg·kg body weight-1·d-1 1 Values are means ± SEM, n = 21–68. Total fumonisin concentration was calculated by summing the concentrations of fumonisin B1+ fumonisin B2+ fumonisin B3 determined by LC/MS and correcting for the mean extraction efficiency (19). The frequency is the percentage of the total samples, n = 236, in each grouping in column 1. 2 The consumption data for urban and rural are from the XI National Census (30) as reported in Fuentes et al. (9). Urban, 102 g/d maize; Central Highlands, 330 g/d maize; rural, 454 g/d maize. 3 The data for the Central Highlands are from a recall study in women conducted by INCAP in 1999 to 2000 where the mean tortilla consumption was 14/d, the mean consumption of other nixtamalized maize products was 72.5 g/d, and the weight of the women surveyed, n = 92, was 55 kg. The fresh weight of nixtamalized products consumed was converted to dry weight. Consumption (102–454 g/d maize) is the calculated dry weight of maize contained within the nixtamalized products. 4 The estimated values are the µg·kg body weight–1·d–1 corrected for the reduction of total fumonisins by 0.54 (0.46 remaining) due to nixtamalization (6). Total fumonisin includes fumonisins B1+B2+B3 plus total hydrolyzed fumonisins (HFB1+HFB2+HFB3), which are found in approximately equal molar amounts in tortillas produced by the traditional Mayan method (6).Values >2 exceed the PMTDI for fumonisins (3), assuming that hydrolyzed fumonisins would be equally toxic to humans compared with the B series fumonisins.

  30. Mycotoxins: a curse to poor people • Cancer • Stunting • Increased HIV transmission • NTD • A number of studies establish a strong correlation between mycotoxins (esp. fumonisin) consumption and those human health problems. • There are plausible and well established biological mechanisms for the effects • A stronger causal relationship may be proved by feeding high-levels of fumonisin to randomly assigned humans (women and children) but this is unethical. • The kind of correlation presented may be the best evidence available. DO WE NEED FURTHER EVIDENCE BEFORE ACTING? What could be done to reduce fumonisin contamination?

  31. Options to control fungi • Resistance to infection: • increase resistance to insects (esp. fumonisin) • increase directly resistance to fungi • Breeding and/or transgenesis? • Increase mycotoxin degradation/extraction • Reduce postharvest contaminations (esp. aflatoxins) by processing (e.g. sieving the grains to remove broken kernels)

  32. Fusarium Ear Rot Germplasm Enhancement of Maize Susceptible Line Resistant Line Variability in maize germplasm for resistance to Fusarium Slide from www.nccpb.org/ppts/2009-PublicSectorCrop.ppt Bill Dolezal, Pioneer Hi-Bred Int’l, Woodland, CA (2005)

  33. Resistance to Fusarium infection Chen ZY, Brown RL, Damann KE, Cleveland TE (2010) PR10 expression in maize and its effect on host resistance against Aspergillus flavus infection and aflatoxin production. Mol Plant Pathol. 11:69-81. Brown RL, Chen ZY, Menkir A, Cleveland TE, Cardwell K, Kling J, White DG (2001) Resistance to aflatoxin accumulation in kernels of maize inbreds selected for ear rot resistance in West and Central Africa. J Food Prot. 64:396-400. Menkir A, Brown RL, Bandyopadhyay R, Chen ZY, Cleveland TE (2006) A USA-Africa collaborative strategy for identifying, characterizing, and developing maize germplasm with resistance to aflatoxin contamination. Mycopathologia 162:225-32. Bhatnagar D, Cary JW, Ehrlich K, Yu J, Cleveland TE (2006) Understanding the genetics of regulation of aflatoxin production and Aspergillus flavus development. Mycopathologia 162:155-66. Brown RL, Cleveland TE, Woloshuk CP, Payne GA, Bhatnagar D (2001) Growth inhibition of a Fusarium verticillioides GUS strain in corn kernels of aflatoxin-resistant genotypes. Appl Microbiol Biotechnol. 57:708-11. Tubajika KM, Damann KE. (2001) Sources of resistance to aflatoxin production in maize. J Agric Food Chem. 49:2652-6.

  34. Flavonoid and anthocyanins reduce mycotoxin infection of maize seeds Selected colored lines show 65-87% lower levels of fumonisin B1 compared to control yellow lines Fumonisin B1 (ppm) EU limit 1126/2007 4 ppm maximum levels in maize seeds Chiara Tonelli, Roberto Pilu, Katia Petroni University of Milan, IT

  35. DIMBOA • Major secondary metabolites among poaceae • Glucosides are stored in vacuoles as inactive compounds; glucosidases specific for activation are in the plastids • DIMBOA confers resistance to leaf-feeding by several corn borer species and decreases in vivo endoproteinase activity in the larval midgut of the European corn borer limiting the availability of amino acids and reducing larval growth • Improve resistance by breeding varieties with increased levels of these natural pesticides http://www.plantphysiol.org/cgi/content/full/146/3/1053

  36. Breeding vs. transgenesis • There is variability in maize germplasm for resistance to fungi and/or insects • Unclear the effect of natural pesticides or other compounds on human heath (several antinutritional factors are natural pesticides) • No clear evidence for reducing aflatoxin content by controlling insects (some reports however do) • Infection by Aspergillus flavus seems not to require wounding • A positive effect of Bt trait on yield and reduction of fumonisin content

  37. Fumonisin and Bt corn Reducing insect damage in corn also reduces the risk of Fusarium contamination. Several (field) studies have shown that Bt corn has significantly lower levels of fumonisin. • Hammond et al. (2003) Reduction of fumonisin mycotoxins in Bt corn. Toxicologist 72(S-1): 1217. • Hammond et al. (2004) Lower fumonisin mycotoxin levels in the grain of Bt corn grown in the United States in 2000-2002. J Agric Food Chem. 52:1390-7. • Bakan et al. (2002) Fungal growth and fusarium mycotoxin content in isogenic traditional maize and genetically modified maize grown in France and Spain. J Agric Food Chem. 50:728-31. • Duvick (2001) Prospects for reducing fumonisin contamination of maize through genetic modification.Environ Health Perspect. 109 Suppl 2:337-42. • Dowd (2000) Indirect reduction of ear molds and associated mycotoxins in Bacillus thuringiensis corn under controlled and open field conditions: utility and limitations. J Econ Entomol. 93:1669-79. • Munkvold and Hellmich (1999) Comparison of fumonisin concentrations in kernels of transgenic Bt maize hybrids and nontransgenic hybrids. Plant Dis 83:130–138. • Dowd (2001) Biotic and abiotic factors limiting efficacy of Bt corn in indirectly reducing mycotoxin levels in commercial fields. J Econ Ent 94: 1067–1074. • Williams et al. (2002) Aflatoxin accumulation in conventional and transgenic corn hybrids infested with southwestern corn borer (Lepidoptera: Crambidae). J Agric Urban Entomol 19(4): 227–236. • Magg et al. (2003) Concentration of moniliformin produced by Fusarium species in grains of transgenic Bt maize hybrids compared to their isogenic counterparts and commercial varities under European corn borer pressure. Plant Breeding, 122: 322-327. • Barros et al. (2009) Fungal and mycotoxin contamination in Bt maize and non-Bt maize grown in Argentina. World Mycotoxin Journal 2:53-60. • Brookes G, 2007. The benefits of adopting genetically modified, insect resistant (Bt) maize in the European Union (EU): first results from 1998-2006 plantings. www.pgeconomics.co.uk

  38. Selected examples of the effect of the Bt trait on fumonisin content (data presented in the next 5 slides) L. Folcher, M. Delos, E.Marengue, M. Jarry, A.Weissenberger, N. Eychenne, C. Regnault-Roger (2010) Lower mycotoxin levels in Bt maize grain. Agron. Sustain. Dev. 30:711–719 Pietri A., Piva G., 2000. Occurrence and control of mycotoxins in maize grown in Italy. Proceedings of the VI International Feed Production Conference, 226-236, Piacenza, November 27-28, 2000. Masoero F., Moschini M., Rossi F., Prandini A., Pietri A. (1999) Nutritive value, Mycotoxin contamination and in vitro rumen fermentation of normal and genetically modified corn (cry 1A(b)) grown in northern Italy. Maydica, 44: 205-209. Maggiore T., unpublished data from the 2005 Landriano field trial (for the yield data: http://www.vivereinarmonia.it/allegati/pdfonline_6483.pdf ) Tatli, F.; Gullu, M.; Ozdemir, F., (2004) Determination of fungi species, relationships between ear infection rates and fumonisin quantities in Bt maize. Bulletin OILB/SROP 27(3): 161-164 Other references Papst, C., H. F. Utz, A. E. Melchinger, J. Eder, T. Magg, D. Klein and M. Bohn (2005) Mycotoxins Produced by Fusarium spp. in Isogenic Bt vs. non-Bt Maize Hybrids under European Corn Borer Pressure, Agron. J. 97:219-224.

  39. Grain levels of FB1 and B2 at harvest in Bt and non-Bt (isogenic) maize plots for 2005 and 2006 Field trials in France Red bars: 4000 ppb threshold (EU Rule) Folcher et al. (2010) Agron. Sustain. Dev. 30:711–719

  40. Field trials in USA Total fumonisin concentration (ppm; mean  SD) from Hammond et al., 2004 Based on 178 Field trials

  41. Field trials in Northern Italy

  42. Landriano field trial (2005) P66 is isogenic to P67, Cecilia is isogenic to Elgina *European Corn Borer larvae number at harvest within the plant (stalk, peduncle and ear) Unpublished data from T. Maggiore (Milan Univ.) Field trial funded by the Italian government through INRAN

  43. Field trials in Turkey Fumonisin concentrations determined by ELISA [Insecticide-treated (+) and untreated plots (-)] Tatli, F.; Gullu, M.; Ozdemir, F., (2004) Determination of fungi species, relationships between ear infection rates and fumonisin quantities in Bt maize. Bulletin OILB/SROP 27(3): 161-164

  44. Mycotoxins in the EU The Rapid Alert System for Food and Feed (RASFF) Annual Report 2006 Fumonisins As regards fumonisins, in 2006 nine notifications concerned maize products originating from Italy. http://ec.europa.eu/food/food/rapidalert/report2006_en.pdf Annual Report 2008 As in previous years, also in 2008 mycotoxins are the hazard category with the highest number of notifications. The RASFF received in 2008 a total of 931 notifications on mycotoxins, of which as many as 902 concerned aflatoxins. This means that the decreasing trend of the previous years is inversed with an increase of 28% for aflatoxins and 23% for mycotoxins in general. From the Annual Report 2006

  45. Fumonisin and organics "Last fall [2006], the United Kingdom’s Food Standards Agency detected alarming concentrations of the toxin [fumonisin] in all six brands of organic corn meal subjected to testing, for a failure rate of 100%. The average level of contamination was almost 20 times higher than the safety threshold Europeans have set for fumonisin."- The Organic Myth, June 4, 2010 http://www.heymiller.com/2010/06/the-organic-myth/ Country of origin: Italy https://webgate.ec.europa.eu/rasff-window/portal/index.cfm?event=notificationDetail&NOTIF_REFERENCE=2003.266

  46. Background information on Bt maize in Spain (2010) Previous slide is from a presentation of the Spanish Ministry of Environment, given by Mrs Esteban http://www.efsa.europa.eu/en/events/documents/gmo090914-p13.pdf 67.726* ha, 21% of the total 322.500 ha of grain maize 201varieties of GM maize registered in the European Catalogue          12 companies marketing thesevarieties in Spain  Surface is lower when compared to 2009 (76.057 ha) % is more or less the same (lower overall maize plantings) * http://www.mapa.es/agricultura/pags/semillas/estadisticas/serie_maizgm98_06.pdf Organic maize is less than 1% of the total maize cultivation area but accounts for 31% of the alerts Bt maize is 21% of the total but accounts for 0% of the alerts

  47. Food security and economics Maize yield losses of 20-30% due to grain weevils are common in Africa, totaling around 5 Mt a year (Gressel et al., 2004). X-ray of maize grains infested with grain weevils http://blogs.nationalinsectweek.co.uk/chrishaines/files/2010/07/LowResx-ray_infested_maize.jpg Maize weevil (Sitophilus zeamais) http://4.bp.blogspot.com/_lDfVXMCBuu0/S6iUCIYBV4I/AAAAAAAAERU/dLJulbxAV3A/s1600/Maize-weevil-3.jpg Bt proteins are available to target such pests. They could significantly improve food security and food safety in developing countries

  48. It is important to remember that corn in the developing countries is mainly food for humans, but in developed countries is feed for animals Developed countries have monitoring programs and institution to keep the problem under control and therefore this is not a major health issue. In developing countries regulations, if and when enforced, may protect the urban population, not the subsistence farmers (80% population) as most of the grains are stored in the farm for household usage. In general Bt corn is not a silver bullet (to solve all the problems related to insect and mycotoxin contamination in maize) not even for fumonisins. Several other factors, such as genetic background, climate, environmental conditions and postharvest processing, are important. It is however a very useful tool which can drastically reduce fumonisin risk in maize, especially when combined with other practices.

  49. Local solutions needed The Bt maize developed in the west and made available to Africa controls only one of the two stem borers vectoring the fungus producing fumonisins  current Bt corn would be a partial help only, at present, in Africa. None of the Bt toxins used in the west or Africa control the moths and beetles that vector the fungus producing aflatoxins, although such Bts must exist, and they must be targeted for expression the ear and the seed, as infection for aflatoxin (but not fumonisin) can also occur during post-harvest storage.Gressel (2008) Genetic glass ceilings: transgenics for crop biodiversity, Chapter7

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