title: Aflatoxigenic fungi and aflatoxin in cocoa.
abstract: This paper reports the occurrence of aflatoxigenic fungi and the presence of aflatoxins in 226 cocoa samples collected on Brazilian farms. The samples were taken at various stages of fermentation, drying and storage. A total of 819 potentially aflatoxigenic fungi were isolated using Dichloran 18% Glycerol agar after surface disinfection, and identified by standard techniques. The ability of the fungi to produce aflatoxins was determined using the agar plug technique and TLC. The presence of aflatoxins in cocoa samples was determined by HPLC using post-column derivatization with bromide after immunoaffinity column clean up. The aflatoxigenic fungi isolated were Aspergillus flavus, A. parasiticus and A. nomius. A considerable increase in numbers of these species was observed during drying and storage. In spite of the high prevalence of aflatoxigenic fungi, only low levels of aflatoxin were found in the cocoa samples, suggesting the existence of limiting factors to the accumulation of aflatoxins in the beans.
authors.affiliation: Universidade Federal de Santa Maria (UFSM), Departamento de Tecnologia e Ciência de Alimentos, CEP 97105, 900, Santa Maria/RS, Brazil. mvc@smail.ufsm.br
authors.forename: Marina V
authors.initials: MV
authors.lastname: Copetti
authors.forename: Beatriz T
authors.initials: BT
authors.lastname: Iamanaka
authors.forename: José Luís
authors.initials: JL
authors.lastname: Pereira
authors.forename: Maria H
authors.initials: MH
authors.lastname: Fungaro
authors.forename: Marta H
authors.initials: MH
authors.lastname: Taniwaki
mesh_terms: D000348:Aflatoxins / Q000032:analysis / Q000096:biosynthesis*; D001230:Aspergillus / Q000302:isolation & purification* / Q000378:metabolism; D001938:Brazil; D002099:Cacao / Q000382:microbiology*; D002851:Chromatography, High Pressure Liquid; D005285:Fermentation; D005506:Food Contamination / Q000032:analysis; D005511:Food Handling
chemical_list: D000348:Aflatoxins