title: Volatile profiles and aflatoxin production by toxigenic and non-toxigenic isolates of Aspergillus flavus grown on sterile and non-sterile cracked corn.
abstract: Aspergillus flavus is a saprophytic fungus which can grow on corn and produce aflatoxins which render it unsafe for consumption as food and feed. In this study, aflatoxin and non-aflatoxin producing isolates of A. flavus were grown separately on wet (20% water added), sterile or non-sterile cracked corn. Wet and dry cracked corn controls were included as needed. Secondary metabolic volatiles were identified and aflatoxin concentrations determined over a 12-day period. Volatiles unique to the toxigenic A. flavus isolates were determined by comparison with volatiles produced by the respective corn controls and the non-toxigenic A. flavus isolate. The number and identity of the volatiles produced by these A. flavus isolates varied by isolate, whether sterile or non-sterile corn was the substrate, and the sampling day. Overall, most of the volatiles were produced before day 8 after inoculation. Aflatoxin production was 10-fold lower on the sterile corn, compared to the non-sterile corn. Volatiles unique to the aflatoxin producing isolates were identified on both substrates after comparison with those produced by the non-aflatoxin producing isolate, as well as the corn control samples. Results indicate that several factors (substrate, fungal isolate, culture age) affect volatile and aflatoxin production by A. flavus.
authors.affiliation: Southern Regional Research Center, USDA, New Orleans, LA, USA. Anthony.DeLucca@ars.usda.gov
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: De Lucca
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Boue
authors.forename: Carol
authors.initials: C
authors.lastname: Carter-Wientjes
authors.forename: Deepak
authors.initials: D
authors.lastname: Bhatnagar
mesh_terms: D016604:Aflatoxin B1 / Q000096:biosynthesis*; D001231:Aspergillus flavus / Q000737:chemistry* / Q000145:classification / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D011108:Polymers / Q000737:chemistry; D013045:Species Specificity; D013997:Time Factors; D055549:Volatile Organic Compounds / Q000032:analysis*; D003313:Zea mays / Q000382:microbiology*
chemical_list: D011108:Polymers; D055549:Volatile Organic Compounds; C010514:tenax; D016604:Aflatoxin B1