Related Experiment Video
Updated: Oct 22, 2025
Metabolomic Analysis of Barley by Gas Chromatography/Mass Spectrometry
Published on: November 8, 2024
Effect of Long-Term Storage on Mycobiota of Barley Grain and Malt
Soňa Felšöciová1, Przemysław Łukasz Kowalczewski2, Tomáš Krajčovič3
1Department of Microbiology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture, Tr. A. Hlinku 2, 949-76 Nitra, Slovakia.
Abstract:
Contamination of malting barley grain and malt with micromycetes sampled at various periods post-harvest (3rd, 6th, and 9th month of storage) and types of storage (storage silo and floor warehouse) was investigated. Each of these barley grain samples was malted. This article reports on the changes in the fungal microbiome composition and their overall count in barley grain and malt. From the surface-disinfected barley grain samples collected immediately after harvest, there were eight genera isolated, with a predominance of Alternaria. A small increase of isolated microfungi was detected in barley stored in silo for 3 and 6 months (from 142 isolates to 149) and decreased below the number of isolates in barley before storage (133 isolates). Fungal count during storage gradually decreased up to 9 month in barley stored in floor warehouse (from 142 isolates to 84). The initial total count of microscopic fungi in malt before storage was the highest (112 isolates) with 7 genera detected, compared to malts prepared from barley stored for longer time (54 isolates, 7 genera, 9th month of storage). Alternaria was the most abundant and frequent genus. Quantitative representation of the filamentous microscopic fungi was lower compared to yeasts especially in barley and malt prepared from barley stored at third month of storage in both type of storage. Yeasts were identified from all grain samples and malt samples with mass spectrometry. Most attention was given to the widely distributed fungus Penicillium, 79% of strains produced at least one mycotoxin detected under in vitro assays using the TLC method (97% of them produced griseofulvin, 94% CPA, 79% patulin, 14% roquefortin C, and penitrem A was produced by two screening strains under laboratory conditions). It is therefore important to monitor the microflora throughout the production cycle of "barley to beer".
Insights
Barley storage impacts fungal contamination. Yeasts and molds like Alternaria and Penicillium were prevalent, with some Penicillium strains producing mycotoxins, highlighting the need for microflora monitoring in barley to beer production.
Area of Science:
- Agricultural Science
- Food Microbiology
- Mycology
Background:
- Malting barley is susceptible to fungal contamination during post-harvest storage.
- Storage conditions (silo vs. floor warehouse) and duration (3, 6, 9 months) influence fungal microbiome composition.
- Microfungi, including yeasts and filamentous fungi, can impact barley quality and safety.
Purpose of the Study:
- To investigate the changes in fungal microbiome composition and counts in malting barley grain and malt.
- To assess the impact of different storage periods and types on fungal contamination.
- To identify predominant fungal genera and evaluate mycotoxin production by Penicillium strains.
Main Methods:
- Barley grain and malt samples were collected at 3, 6, and 9 months post-harvest from silo and floor warehouse storage.
- Surface-disinfected barley grain samples were used for fungal isolation and identification.
- Microfungi were quantified, and dominant genera like Alternaria and Penicillium were identified.
- Yeasts were identified using mass spectrometry.
- Mycotoxin production by Penicillium strains was assessed using thin-layer chromatography (TLC).
Main Results:
- Alternaria was the predominant genus in freshly harvested barley.
- Fungal counts in barley grain decreased over storage, particularly in floor warehouse storage.
- Malt prepared from stored barley showed lower fungal counts compared to malt from fresh barley.
- Yeasts were more abundant than filamentous fungi in barley and malt, especially after 3 months of storage.
- Penicillium strains frequently produced mycotoxins, including griseofulvin, CPA, and patulin.
Conclusions:
- Storage duration and type significantly alter the fungal microbiome of malting barley and subsequent malt.
- The prevalence of mycotoxin-producing Penicillium strains necessitates careful monitoring of barley microflora.
- Continuous monitoring of microflora throughout the barley-to-beer production cycle is crucial for ensuring product safety and quality.
More Related Videos
10:10Mass Production of Entomopathogenic Fungi, Metarhizium robertsii and Metarhizium pinghaense, for Commercial Application Against Insect Pests
Published on: March 31, 2022
06:53In Vivo Monitoring of Transcriptional Activity During Metabolic Transition Using a Bioluminescent Reporter in Yeast
Published on: February 21, 2025
