ARS | Publication request: Volatile profiles of toxigenic and non-toxigenic Aspergillus flavus using SPME for solid phase extraction

Submitted to: Annals of Agriculture and Environmental Medicine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 19, 2010
Publication Date: December 15, 2010
Citation: De Lucca II, A.J., Boue, S.M., Carter-Wientjes, C.H., Bland, J.M., Bhatnagar, D., Cleveland, T.E. 2010. Volatile profiles of toxigenic and non-toxigenic Aspergillus flavus using SPME for solid phase extraction. Annals of Agriculture and Environmental Medicine. 17:301-308.

Interpretive Summary: Sometimes stored corn gets wet due to imperfect storage conditions. At certain conditions conducive to growth, such wet corn can serve as a nutrient source for fungi that naturally occur on corn. These fungi are present in the soil and on the corn plants in the field. One such fungus is named Aspergillus flavus. When they grow these fungi can produce toxins that make the corn unsafe for human and animal consumption. During metabolism, such fungi produce minute levels of gases. This work showed that different isolates of Aspergillus flavus produce many gases. Some of these gases are produced by the different isolates of this fungus. However, some gases are unique to the different isolates. This work indicates that it may be possible to detect the presence of fungi growing on stored corn if the gases can be chemically detected and identified.

Technical Abstract: Toxigenic and atoxigenic strains of Aspergillus flavus were grown on potato dextrose agar (PDA) and wetted sterile, cracked corn for 21 and 14 days, respectively. Volatile compounds produced by A. flavus, as well as those present in the PDA controls and sterile cracked corn, were collected using solid phase extraction (SPME) and identified by GC/MS. Results show that growth substrate had a major impact on the number and type of volatiles detected. Growth on sterile cracked corn produced many more volatiles than did potato dextrose agar. There were also differences observed in the type of volatiles produced between toxigenic and non-toxigenic isolates as well as between isolates of the same toxigenic grouping.