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Updated: Jul 13, 2026
Quantification of Fungal Colonization, Sporogenesis, and Production of Mycotoxins Using Kernel Bioassays
Published on: April 23, 2012
Factors determining accumulation of mycotoxin producers in cereal grain during harvesting
Albinas Lugauskas1, Algirdas Raila, Egidijus Zvicevicius
1Laboratory of Biodeterioration Research, Institute of Botany, Vilnius, Lithuania. lugauskas@botanika.lt
Abstract:
During the meteorologically contrasting period of 2003-2005, the contamination of winter wheat, malt barley and fodder barley grain with micromycetes during grain harvesting and preparation for storage was investigated. Micromycetes of over 70 species ascribed to 16 genera were isolated and identified, the density of their populations in grain was determined. Micromycetes with a population density of >50% were attributed to dominant species. Short biological characteristic, ecological peculiarities of the dominating micromycetes are provided; factors determining intensity of their development and abilities to synthesise and excrete toxic metabolites are indicated. The importance of grain drying for stabilisation of its contamination with micromycete propagules is highlighted. It is noted that in grain dried in shaft dryer using air at 90 degrees C the number of cfu (colony forming units) was reduced from 2.2 to 8.2 times. When active ventilation is applied, conditions favourable for the development of micromycetes remain longest in the upper layers of the mound. The airflow passing through the layer of damp grain inhibits the development of micromycetes, but an increase of comparative air flow for more than 500 m3x(txh)(-1) did not reduce the abundance of micromycete cfu. After drying Alternaria alternata, Fusarium avenaceum, F. culmorum, Penicillum verrucosum dominated in wheat grain; Aspergillus flavus, Bipolaris sorokiniana, Fusarium chlamydosporum, F. culmorum, F. tricinctum in malts barley grain; Fusarium avenaceum, F. culmorum, F. tricinctum, Alternaria alternata in fodder barley grain. It has been determined that all micromycetes recorded on grain after drying are potential producers of toxic metabolites, i.e. are hazardous to human health.
Insights
Grain drying significantly reduces micromycete contamination, but dominant fungal species like Fusarium and Alternaria remain, posing health risks. Proper drying is crucial for safe grain storage and human health.
Area of Science:
- Agricultural Science
- Mycology
- Food Safety
Background:
- Micromycete contamination of cereal grains is a significant concern during harvest and storage.
- Over 70 micromycete species from 16 genera were identified in wheat and barley grains.
- Dominant species were identified based on population density exceeding 50%.
Purpose of the Study:
- To investigate micromycete contamination in winter wheat, malt barley, and fodder barley during 2003-2005.
- To characterize dominant micromycetes, their ecology, and toxin-producing potential.
- To evaluate the effectiveness of grain drying and ventilation on micromycete populations.
Main Methods:
- Isolation and identification of micromycetes from harvested grains.
- Determination of micromycete population density and dominant species.
- Assessment of grain drying (90°C shaft dryer) and active ventilation effects on fungal contamination.
Main Results:
- Grain drying reduced colony forming units (cfu) by 2.2 to 8.2 times.
- Active ventilation inhibited micromycetes in lower grain layers, but upper layers remained favorable for growth.
- Specific micromycete species dominated post-drying, including Fusarium and Alternaria, all potential toxin producers.
Conclusions:
- Grain drying is vital for stabilizing micromycete contamination.
- Despite drying, surviving micromycetes pose a health hazard due to potential toxic metabolite production.
- Effective management of micromycete contamination is essential for grain safety.
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