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Before undergoing the various malting operations, barley like other cereals, is often naturally contaminated by various microorganisms, mainly composed of bacteria, yeasts as well as filamentous fungi. These microorganisms contaminate and colonize the barley grain in the field and during its handling and storage. In addition, the conditions of malt...
Citations
... Some storage baskets used in the North Central region of Namibia are made of Makalani palm leaves. Traditional methods of storage, which include the use of wood ash to guard from insect infection, could also be sources of fungal contamination [43]. Due to scarcity of trees in the Oshana region, some farmers have resorted to the use of plastic storage containers, which are commercially available. ...
Mycological (mycotoxigenic Fusarium and aflatoxigenic Aspergillus spp.) and multiple mycotoxins [aflatoxin B1 (AFB1), fumonisin B (FB), deoxynivalenol and zearalenone] surveillance was conducted on raw whole grain sorghum (Sorghum bicolor) and pearl millet (Pennisetum glaucum) produced on smallholder farms, and processed products sold at open markets in northern Namibia. Fungal contamination was determined with morphological methods as well as with quantitative Real-Time PCR (qPCR). The concentrations of multiple mycotoxins in samples were determined with liquid chromatography tandem mass spectrometry. The incidence of mycotoxigenic Fusarium spp., Aspergillus flavus and A. parasiticus, as well as the concentrations of AFB1 and FB were significantly (P < 0.001) higher in the malts as compared to the raw whole grains, with Aspergillus spp. and AFB1 exhibiting the highest contamination (P < 0.001). None of the analysed mycotoxins were detected in the raw whole grains. Aflatoxin B1 above the regulatory maximum level set by the European Commission was detected in sorghum (2 of 10 samples; 20%; 3–11 µg/kg) and pearl millet (6 of 11 samples; 55%; 4–14 µg/kg) malts. Low levels of FB1 (6 of 10 samples; 60%; 15–245 µg/kg) were detected in sorghum malts and no FB was detected in pearl millet malts. Contamination possibly occurred postharvest, during storage, and/or transportation and processing. By critically monitoring the complete production process, the sources of contamination and critical control points could be identified and managed. Mycotoxin awareness and sustainable education will contribute to reducing mycotoxin contamination. This could ultimately contribute to food safety and security in northern Namibia where communities are exposed to carcinogenic mycotoxins in their staple diet.
... Due to the warm, moist, and likely unhygienic conditions during the traditional malting and milling processes, the growth of mycotoxigenic fungi is stimulated [6]. In addition, mycotoxigenic fungi can infiltrate deep into sorghum matrices and produce mycotoxins during the pre-harvest, storage, transportation, processing, and marketing stages [7]. ...
Sorghum malts, which are important ingredients in traditional fermented beverages, are commonly infected by mycotoxigenic fungi and mycotoxins may transfer into the beverages, risking consumers’ health. Liquid chromatography–tandem mass spectrometry was used to determine variation of fungal metabolites in 81 sorghum malts processed for brewing of Namibian beverages, otombo (n = 45) and omalodu (n = 36). Co-occurrence of European Union (EU)-regulated mycotoxins, such as patulin, aflatoxins (B1, B2, and G2), and fumonisins (B1, B2, and B3) was detected in both malts with a prevalence range of 2–84%. Aflatoxin B1 was quantified in omalodu (44%) and otombo malts (14%), with 20% of omalodu malts and 40% of otombo malts having levels above the EU allowable limit. Fumonisin B1 was quantified in both omalodu (84%) and otombo (42%) malts. Emerging mycotoxins, aflatoxin precursors, and ergot alkaloids were quantified in both malts. Notably, 102 metabolites were quantified in both malts, with 96% in omalodu malts and 93% in otombo malts. An average of 48 metabolites were quantified in otombo malts while an average of 67 metabolites were quantified in omalodu malts. The study accentuates the need to monitor mycotoxins in sorghum malts intended for brewing and to determine their fate in the beverages.
... Also, the steeping and germination stages of malting provide solubilized or partially solubilized nutrients that can be utilized by microorganisms. Some proliferation of microorganisms may occur by the end of steeping, but proliferation is the highest during germination (36). ...
The primary aim of this research was to investigate the effect of dilute alkaline steeping on molds and toxicity of maize malt. Samples of maize were collected from one farm located in the Serbian autonomous region Vojvodina. Steeping regimes were performed by using 0.1, 0.2, and 0.3% NaOH solutions. The effects of these solutions on mold contamination, total aflatoxin (AFLA), deoxynivalenol (DON), zearalenone (ZON), rootlet length, moisture, total nitrogen, content of protein, fat content, ash content, content of total carbohydrates, and energy value of maize malt were evaluated. Steeping in 0.1, 0.2, and 0.3% NaOH reduced the levels of molds from 10⁶ to 10⁴ CFU/g, and steeping in 0.3% NaOH eliminated some of the mold genera. Also, it significantly reduced (P < 0.05) the level of total AFLA, DON, and ZON. However, steeping in (control) water also significantly reduced (P < 0.05) the level of DON and ZON. Malting also significantly reduced (P < 0.05) total nitrogen and therefore content of proteins. However, steeping in 0.1, 0.2, and 0.3% NaOH caused significantly smaller reductions (P < 0.05). Significant reduction (P < 0.05) was also observed in the rootlet length, content of fat, and ash content. Steeping in 0.3% NaOH is proposed as a method for the reduction of mold and AFLA, DON, and ZON contamination during maize malting. Energy value of maize increases in the malting process regardless of the steeping regime.
