Effet chez le porcelet d'une exposition à un régime co-contaminé en ...

INTRODUCTIONcompared with γ-irradiation and microwave heating. More than 60% of the aflatoxins were found tobe degraded after 30h of exposure to sunlight. The degree of aflatoxin reduction was found to bedependent on the duration of exposure to sunlight. But solar radiation has potential as aninexpensive means of degrading aflatoxins in tropical countries. Regarding γ-irradiation treatment,40% of aflatoxin content was destroyed and these results were in agreement with Farag et al. (1995),who found that an 83% reduction of aflatoxin after a 20-kGy dose of γ-irradiation of yellow corn wasachieved. On the contrary, Aziz and Youssef (2002) found that the dose of 20 kGy was sufficient tocompletely destroy AFB1 in yellow corn.The effect of γ-irradiation on fumonisin B1 and fumonisin B2 occurring in maize materials hasbeen investigated together with the stability of fumonisins in γ-irradiated maize stored at differenttemperatures (-18 to +40°C) for different periods (2, 4, 13 and 26 weeks). Fifteen KGy γ-irradiationwas required to sterilize efficiently maize flour. This process caused a decrease in fumonisin contentof about 20%. The stability studies showed that fumonisins are stable in γ-irradiated maize for atleast 6 months at 25°C or at least 4 weeks at 40°C (Visconti et al., 1996).Paster et al. (1985) indicated that pure ochratoxin A (OTA) is stable even at 75 kGy but Refai et al.(1996) showed that a dose of 15 or 20 kGy is sufficient for complete destruction of OTA in yellowcorn. Similarly, Aziz and Youssef (2002) reported 75% of detoxification in yellow corn at a radiationdose of 20 kGy.For zearalenone, complete destruction was obtained when a dose of 20 kGY was applied in yellowcorn (Aziz and Youssef, 2002).Other ionizing radiations such as microwave and convection heating have been reported by Young(1986) to be partially successful in lowering deoxynivalenol level in naturally contaminated corn.In conclusion, physical methods outlined in this first part can be divided in two categories withregard to their initial applications. Some methods have been specifically developed for mycotoxinsdecontamination (such as sorting, cleaning or washing); whereas others are industrial processes(such as milling, irradiation, ethanol fermentation or extrusion) initially developed for other purposesthan mycotoxins reduction, that have shown an interest in the fighting strategy against mycotoxins.The first category can be considered as a first step in the removal of mycotoxins from maize. Besidesthe substantial efficiency of these approaches, most of the criteria listed by the FAO guidelines arefulfilled : cheap and simple, no production of toxic metabolites, and no change in the nutritionalvalue and properties of raw materials. Nonetheless, application of these techniques on a commercialscale raises some problems :59