ABSTRACT
The deoxynivalenol and nivalenol contamination in wheat and by-products obtained through milling was analized by Trucksess method slightly modified in the proportion of acetonitrile-water (3:1).Only one sample of wheat showed deoxynivalenol contamination, 1,200µg/kg.No samples obtained in different stages of the milling were contaminated with deoxynivalenol or nivalenol.In the commercial wheat flours the levels found ranged between 400 and 800µg/kg, as follows: 400µ/kg, 5 samples; 800jug/kg, 1 sample.
ABSTRACT
The aim of the present work was to determine the influence of Alternaria alternata upon aflatoxin production by Aspergillus parasiticus. A mixture of spores of both strains was inoculated in sunflower seeds at 0.90 aw and incubated for 42 days at 28 degrees C +/- 1. The cultures were observed and analyzed every 7 days to determine the infection level of the seeds and the production of aflatoxins. Results showed that when the seeds were inoculated only with Aspergillus parasiticus, 100% were infected from the 7th day. When Aspergillus parasiticus and Alternaria alternata were simultaneously inoculated the infection level of the seeds was 100% for Aspergillus parasiticus following 7 days of inoculation and 0% for Alternaria alternata. After the 14th day of inoculation there was no significant difference in the infection percentage of both strains (approximately 80% of each one). As far as toxin production is concerned a remarkable decrease was observed when seeds were inoculated with both strains simultaneously. In accordance to the results, Alternaria alternata would not compete with Aspergillus parasiticus in colonization of seeds but would either degrade the aflatoxins by Aspergillus parasiticus or compete for aflatoxin biosynthesis precursors. Alternaria alternata could also secrete some substance that specifically inhibits aflatoxin synthesis.
Subject(s)
Aflatoxins/biosynthesis , Alternaria/metabolism , Aspergillus/metabolism , Helianthus/microbiology , Mitosporic Fungi/metabolism , Seeds/microbiologyABSTRACT
The study of the incidence of aflatoxins, zearalenone, and deoxynivalenol was the aim of this work. This investigation was carried out upon recently harvested corn samples collected in the Departamento of Rio Cuarto, Province of Córdoba, Argentina. 150 samples of corn were analized to investigate aflatoxins B1, G1, and zearalenone contamination. Out of these 150 samples 58 were selected and deoxynivalenol was examined.The incidence value for aflatoxin B1 was of 3.3% (5 samples), aflatoxin G1 1.3 % (2 samples), and zearalenone 6 % (9 samples).The analysis of the 58 samples showed that 24% of them were contaminated with deoxynivalenol.
