title: Time of Aspergillus flavus infection and aflatoxin formation in ripening of figs.
abstract: Figs in an orchard were inoculated with an aflatoxigenic Aspergillus flavus strain in two ways by spore injection or by dusting at three maturation stages: firm ripe, shrivelled, and dried. Fruits were individually examined for fungal development and analyzed for aflatoxin B1 (AF B1) after 2, 4, 6, 8 and 10 days. Fruit injected at the first stage showed fungal development and AF B1 contamination within two days. The toxin level increased sharply to 1 ppm after 10 days. The mean level of AF B1 (284.75 ng/g) was significantly higher than those observed in other conditions. Figs dusted at the first stage showed only a tiny fungal growth even after 10 days. AF B1 appeared after 6 days with a low frequency (35%), mean level (7.6 ng/g) and a great variation among figs (0.22-15 ng/g). Among fruits inoculated during the shrivelled fig and dried fruit stages, no fungal growth was observed and AF B1 was detected with a lower incidence in association with low mean levels (less than 1.25 ng/g). Methods of prevention of aflatoxin contamination at the critical step, the firm ripe stage, are discussed.
authors.affiliation: Station de Pharmacologie-Toxicologie, Institut National de la Recherche Agronomique, Toulouse, France.
authors.forename: H
authors.initials: H
authors.lastname: Boudra
authors.forename: J
authors.initials: J
authors.lastname: Le Bars
authors.forename: P
authors.initials: P
authors.lastname: Le Bars
authors.forename: J
authors.initials: J
authors.lastname: Dupuy
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis / Q000096:biosynthesis*; D000704:Analysis of Variance; D001231:Aspergillus flavus / Q000254:growth & development* / Q000378:metabolism; D005516:Food Microbiology; D005638:Fruit / Q000382:microbiology* / Q000502:physiology
chemical_list: D016604:Aflatoxin B1