Sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum (L.) R.Br) are indigenous crops to the African continent. Apart from maize, rice and wheat, these crops are basic staple foods for many rural communities in Africa. The growth and production of these grains can be negatively affected by plant diseases caused by diverse fungal genera. The ability of Fusarium species to produce mycotoxins, including fumonisins (FUM) and moniliformin (MON), that have detrimental health effects for both humans and animals make it important to evaluate their toxin production in crops that are intended for human consumption. Fusarium species occur naturally in maize, sorghum and millet, among other grains. Potentially toxigenic species isolated from grain samples from Nigeria harboured high FUM and MON producing strains. This was confirmed by molecular identification and by chemoprofiling in in vitro grain cultures. Mycotoxin levels of Fusarium species grown on maize patty cultures were compared to levels produced on sorghum and millet patty cultures. FUM and MON profiles of 18 Fusarium proliferatum and two other Fusarium control strains, ie high producers of either one of these toxins, were analyzed. FUM (fumonisin B1, B2 and B3) were extracted with methanol/water and MON with acetonitrile/water. The mycotoxin extracts were cleaned up using strong anion exchange solid phase extraction prior to quantification by reversed-phase HPLC. Results indicated that under conducive conditions, all the strains tested produced FUM, some in relatively large quantities (11/18), ranging from 694-17421 mg/kg culture material. For 8/18 strains the MON levels were >500 mg/kg and up to 8892 mg/kg culture material. Although there are variations in the potential or ability of F. proliferatum isolates to produce either FUM or MON, these fungi can use several grains as a source for toxin production irrespective of their original hosts. This study gives insight into the potential and ability of Fusarium species, isolated from maize, sorghum and millet, to produce mycotoxins on several grain sources, which may have a marked influence on food safety and security, and the potential health risk they hold for many rural communities in Africa.

Vismer HF, Shephard GS, Imrie G, Van der Westhuizen L, Volkwyn Y, Mngqawa P


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  • Received: 08 May 2012
  • Accepted: 08 May 2012
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