Fumonisins are mainly produced by Fusarium verticillioides (syn. moniliforme) as well as by Fusarium proliferatum and they occur predominately in maize and maize-based feeds (Ross et al. 1992).
In 1988 they were first identified and isolated and so far there are 28 fumonisin analogues known (Gelderblom et al. 1988; Rheeder et al. 2002). Fumonisins are divided into four groups: Serial A, B, C and G. With regard to their toxicity the B-type fumonisins represent the most important ones (Marasas 1996). In naturally contaminated food and feed fumonisin B1 represents about 70% - 80% of the total fumonisin content (Krska et al. 2007).
Fumonisins are very polar and water soluble compounds. Unlike other mycotoxins, they have a long chain structure. Chemically, they are polyhydroxyl alkylamines esterified with two carbon acids, i.e. tricarballylic acid (TCA). The four common members of the type B fumonisins differ by presence and position of the free hydroxyl groups respectively (ApSimon 2001). The one-sided or bilateral elimination of TCA results in partial hydrolyzed fumonisin or hydrolyzed fumonisin (HFB1). Fungal colonization and growth and/or mycotoxin production are influenced by a variety of factors. Optimum conditions for fumonisin production are temperatures between 10°C and 30°C with a water activity (amount of free available water) of 0.93 aw (Marin et al. 1999).
A published survey about the occurrence of mycotoxins in Asia initiated by Biomin GmbH together with Romer® laboratories in Singapore reported that 58% out of 960 feed raw material samples were contaminated with fumonisins. In this report the highest level of fumonisins detected was 21.5 mg/kg in a corn sample from China (Rodrigues and Wegleitner 2008). In Europe, levels up to 250 mg/kg were reported in maize from Italy (Bottalico et al. 1995) . Table 1 gives examples on high concentrations of fumonisins found in maize samples around the world.
Table 1: Examples on high concentrations of fumonisins in maize samples
|250||Italy||Bottalico et al. 1995|
|160||Korea||Seo and Lee 1999|
|155||China||Chu and Li 1994|
|122||USA||Wilson et al. 1990|
|117||South Africa||Rheeder and Marasas 1998|
|75||Hungrey||Fazekas et al. 1998|
|21.5||China||Rodrigues and Wegleitner, 2008|
|10.6||China||Chin and Tan, 2006|
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