Practical guidelines to minimise mycotoxin development in UK cereals


Practical guidelines to minimise mycotoxin development in UK cereals, in line with forthcoming EU legislation, using the correct agronomic techniques and grain storage management

October 2002 



1Central Science Laboratory, Sand Hutton, York , YO41 1LZ
2KAS mycotoxins, 6 Fern Drive , Taplow, Maidenhead, Berkshire , SL6 0JS
3Velcourt Ltd., Gordon House, Legbourne, Louth, Lincolnshire , LN11 7LH



Ochratoxin A is a mycotoxin produced by Penicillium verrucosum, a mould that occurs widely in poorly stored cereals in the UK and its occurrence is associated with storage of damp grain. Evaluation of the risk posed by this mycotoxin to human health indicates that its presence in cereals and other food products must be minimised. To this end the European Community have introduced maximum permitted limits for thismycotoxin of 5 µg/kg and 3 µg/kg for whole cereal grains and processed products respectively. The aim of this study was to examine whether different levels of field fungi on cereal grains entering storage affect the growth of the storage fungi and the development of mycotoxins (principally but not exclusively ochratoxin A) post-harvest.

Field trials were caried out in Kent , Hampshire, the Cotswolds and Yorkshire to ensure that the study covered a range of soil types, geographical and climatic locations.  At each site 2 malting barley varieties 2 bread-making wheat and 2 feed wheat were grown in 2000 and 2001.  At each site and for each variety, 24 m x 120 m plots were established and all received 'standard' commercial applications of fertilisers, insecticides, growth regulators and herbicides.  Plots were divided into four sub-plots and different fungicides regimes applied to each sub plot. At harvest, grain was transferred un-dried into 0.5 tonne bags, stored under cover and monitored for moisture content and temperature for 28-42 days. Samples taken at harvest and during the storage period were examined for moulds and for ochratoxin A.

The fungicide application regime used had little eaffect on the composition or amounts of field moulds, in particular sooty moulds, entering storage. Two scenarios were put forward; either field moulds were able to establish themselves on the ear after the activity of the T3 fungicide spray had diminished or mixing of spores in the combine had a levelling effect on spore numbers. Either scenario suggests that trying to manipulate levels of field moulds entering the store to reduce mycotoxin development is not a viable option. Neither P. verrucosum nor ochratoxin A were found in any of the grain samples at harvest. Cereals are put at risk from ochratoxin A (or other mycotoxins) under fairly well defined combinations of temperature and grain moisture content but its actual development is determined by other factors that are strongly indicated but not proven. It is concluded that prediction cannot be made on the basis of grain moisture and temperature alone. There is a strong indication that grain may become contaminated with P. verrucosum during or shortly after harvest through the presence of this fungus in handling equipment or the store environment.

Results from this project confirm that the most effective method for preventing ochratoxin A formation in stored grain is the rapid dying of moist grain, to moisture content below 15%, before storage.

HGCA Project Number: 2281 
Price: £5.50

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