sentences:  The instances reported have usually been on mouldy, or poor quality materials such as wheat, maize, animal feed, hard cheese, pecan nuts and green coffee beans.While this lack of information may be due to deficiencies in the analytical methods, where surveys of good quality products have been carried out with reliable methodology, sterigmatocystin has rarely if ever been found.However, further assurance is required before sterigmatocystin can finally be dismissed as a risk because A. versicolor has been isolated frequently from cereals, grain products, fruits and marmalade, dried meat products and grapefruit juice.