Abstract
Extrusion technology is used widely in the manufacture of a range of breakfast cereals and snacks for human consumption and animal feeds. To minimise consumer exposure to mycotoxins, the levels of deoxynivalenol (DON) and zearalenone (ZON) in cereals/cereal products and fumonisins B1 and B2 (FB1 and FB2) in maize are controlled by European Union legislation. Relatively few studies, however, have examined the loss of Fusarium mycotoxins during processing. The behaviour of FB1, FB2 and fumonisin B3 (FB3), DON and ZON during extrusion of naturally contaminated maize flour and maize grits is examined using pilot-scale equipment. DON and ZON are relatively stable during extrusion cooking but the fumonisins are lost to varying degrees. There is some loss of ZON when present in low concentrations and extruded at higher moisture contents. The presence of additives, such as reducing sugars and sodium chloride, can also affect mycotoxin levels. Moisture content of the cereal feed during extrusion is important and has a greater effect than temperature, particularly on the loss of fumonisins at the lower moistures. The effects are complex and not easy to explain, although more energy input to the extruder is required for drier materials. However, on the basis of these studies, the relationship between the concentration of Fusarium toxins in the raw and finished product is toxin- and process-dependent.
Acknowledgements
These studies were supported by the UK DEFRA Food Safety LINK Programme and UK Food Standards Agency. Maize flour and maize grits were supplied by UK maize millers. Initial mixing and blending was carried by RHM Technology, High Wycombe and analysis of Fusarium mycotoxins at the Central Science Laboratory, York, UK. Extrusion cooking was carried out at the Campden and Chorleywood Food Research Association, Chipping Campden, UK.