Microbial load and mycotoxins from malted pearl millet and sorghum

Abstract

Microbial contamination of pearl millet and sorghum grains during the process of malting can compromise the safety of their resulting products. In Namibia, malts of pearl millet and sorghum are used in making oshikundu/ontaku, omalovu (opaque beer) and exclusively sorghum malts for other alcoholic traditional brews. There is limited research on microbial load and mycotoxins from malts of pearl millet intended for making oshikundu and possibly omalovu. Varieties of pearl millet (Okashana2, Kantana, and Kangara) and sorghum (Macia and Red sorghum) grains were germinated at 30°C for 4 days before drying at 50–55°C for 24 hours. Results showed that malts total microbial load was above the South African recommended limit 6.3 Log cfu/g (2 ×10⁷ cfu/g). However, cereal malts showed no contamination by Salmonella spp., Shigella and coliforms. Regulated mycotoxins aflatoxin, deoxynivalenol, fumonisin and zearalenone were detected from malts irrespective of the cereal. However, detected mycotoxins were below the legal limit set by the European Commission. These suggests that malts may potentially not be of safety concern when it comes to coliforms. Nonetheless, aerobic bacterial load, fungal load and mycotoxins need to be further reduced should the malt be used for oshikundu, omalovu and other low alcoholic brews.