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Separation of mycotoxin-containing sources in grain dust and determination of their mycotoxin potential
Abstract:
Two distinct reservoirs of mycotoxins exist in fungal-infected cereal grains--the fungal spores and the spore-free mycelium-substrate matrix. Many fungal spores are of respirable size and the mycelium-substrate matrix can be pulverized to form particles of respirable size during routine handling of grain. In order to determine the contribution of each source to the level of mycotoxin contamination of dust, we developed techniques to harvest and separate mycelium-substrate matrices from spores of fungi. Conventional quantitative chromatographic analyses of separated materials indicated that aflatoxin from Aspergillus parasiticus, norsolorinic acid from a mutant of A. parasiticus, and secalonic acid D from Penicillium oxalicum were concentrated in the mycelium-substrate matrices and not in the spores. In contrast, spores of Aspergillus niger and Aspergillus fumigatus contained significant concentrations of aurasperone C and fumigaclavine C, respectively; only negligible amounts of the toxins were detected in the mycelium-substrate matrices of these two fungi.
Insights
Mycotoxins in fungal-infected grains originate from spores or the mycelium-substrate matrix. Research shows specific mycotoxins concentrate in the matrix, while others are found in spores, impacting dust contamination levels.
Area of Science:
- Food Science
- Mycology
- Toxicology
Background:
- Fungal-infected cereal grains harbor mycotoxins in two primary reservoirs: fungal spores and the mycelium-substrate matrix.
- Both reservoirs can generate respirable particles during grain handling, contributing to dust contamination.
Purpose of the Study:
- To investigate the distinct contributions of fungal spores and mycelium-substrate matrices to mycotoxin contamination in cereal grain dust.
- To develop and apply methods for separating these two reservoirs for targeted analysis.
Main Methods:
- Development of techniques to harvest and separate fungal spores from the mycelium-substrate matrix.
- Quantitative chromatographic analysis of separated fungal spores and mycelium-substrate matrices for mycotoxin content.
Main Results:
- Aflatoxin, norsolorinic acid, and secalonic acid D were concentrated in the mycelium-substrate matrices, not spores.
- Aurasperone C and fumigaclavine C were found in significant concentrations within spores of Aspergillus niger and Aspergillus fumigatus, respectively, with negligible amounts in their matrices.
Conclusions:
- Mycotoxin distribution between fungal spores and the mycelium-substrate matrix is fungus-specific.
- Understanding these reservoirs is crucial for assessing and mitigating mycotoxin exposure risks from contaminated grain dust.