Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: October 1, 2005
Publication Date: June 1, 2006
Citation: Hua, S. S. 2006. Progress in prevention of aflatoxin contamination in food by preharvest application of a yeast strain, pichia anomala wrl-07. In: Mendez-Vilas, A., editor. Modern Multidisciplinary Applied Microbiology: Exploiting Microbes and Their Interactions. Weinheim, Germany: Wiley-VCH Verlag. p. 323-327. Interpretive Summary: The Food and Agriculture Organization (FAO) estimates that 25% of the world's food crops are affected by mycotoxins, of which the most notorious are aflatoxins. Numerous researchers from universities and USDA locations are conducting nationwide aflatoxin elimination and control studies, including breeding, genetic engineering, and regulation of aflatoxin biosynthesis. Managing aflatoxin contamination via biological control is a promising approach currently available. The results demonstrated that the yeast, P. anomala can modulate spore production of A. flavus on the wounded pistachio nut-fruits. Field spraying of these effective yeasts to pistachio trees may decrease the population of A. flavus in the orchards and prevent further infection by A. flavus as a secondary inocula so that the number of nuts infected by this fungus would be decreased.
Technical Abstract: A total of more than 200 nut-fruits were analysed. Colonization of A. flavus on wounded nut-fruits was 27.1% for the control and 5.1% for the yeast treated nut-fruits respectively. The colony forming unit (CFU) of A. flavus from each infected nut-fruit was enumerated. Average spore production of A. flavus from infected nuts was 5.6x106 and 1.3x106 respectively for the control and yeast sprayed. The total number of A. flavus spores from all infected nut-fruits of the control group was 1.2x108. In contrast the total number of A. flavus spores from the yeast sprayed nut-fruits was only 6.2x106. The results clearly demonstrated that P. anomala prevented colonization of A. flavus on wounds and modulate spore production on infected wounds. Similar results were observed for almond. Field trials are being conducted in corn. One can anticipate that field spraying of this effective yeast to tree-nuts and corn may decrease the population of A. flavus in those environments. Thus, P. anomala is likely to provide an economical means of managing aflatoxin contamination.