###### Abstract  
Maize is an important staple in Africa, which necessitates immediate drying to preserve the postharvest quality. The traditional drying of maize in the open sun is prone to adverse weather and extraneous contamination. In this study, the drying performance of an inflatable solar dryer (ISD) was compared to direct sun drying (DSD) in Gombe Town, Wakiso District (Uganda) by analysing the moisture content, yeasts, moulds, aflatoxin, and colour. The maximum temperature inside the ISD reached 63.7 \({}^{\circ}\)C and averaged 7 \({}^{\circ}\)C higher than the ambient temperature. Maize was dried using both methods to a moisture content below 14% after two days. In one of the received maize lots that was already heavily contaminated after harvest, drying with DSD and ISD reduced the aflatoxin content from 569.6 \(\mathrm{\SIUnitSymbolMicro g}\) kg\({}^{-1}\) to 345.5 \(\mathrm{\SIUnitSymbolMicro g}\) kg\({}^{-1}\) and 299.2 \(\mathrm{\SIUnitSymbolMicro g}\) kg\({}^{-1}\), respectively. Although the drying performance in terms of drying time and product quality regarding colour, yeast, and mould was similar for both drying methods, the advantage of ISD in reducing the risk of spoilage due to sudden rain is obvious. A strategy for the early detection of aflat in maize is recommended to avoid contaminated maize in the food chain. drying characteristics; food safety; innovative solar drying; maize quality; mycotoxin; solar bubble dryer; Africa +
Footnote †: journal: Applied Sciences  
1 Tropics and Subtropics Group, Institute of Agricultural Engineering, University of Hohenheim,  
70599 Stuttgart, Germany; [EMAIL_ADDRESS] (S.S.); [PERSON], [PERSON]_ADDRESS] (S.R. ); [EMAIL_ADDRESS] (J.M.) 2 Alliance of Bioversity International and the International Center for Tropical Agriculture (CIAT), Africa Hub,  
Nairobi P.O. Box 823-00621, Kenya; [PERSON]DDRESS]  
3 Department of Agricultural and Biosystems Engineering, Makerere University, Kampala P.O. Box 7062, Uganda; [EMAIL_ADDRESS]  
4 Correspondence: [PERSON]]; Tel. : +49-711-459-23119  
Footnote †: journal: Applied Sciences  
by mycotoxins [5]. The tropical regions are classified as the most conducive regions for mycotoxin contaminations [6]. Similar issues were revealed in research on the effect of storage time on the contamination of maize in different AEZs of Uganda [7]. It was found that most farmers could hardly dry maize to the required storage moisture content of <14%. At the same time, it was determined that the contamination levels with aflat were higher with longer storage times, with an average contamination level of 30.2 ug kg\({}^{-1}\), especially in humid zones. In East Africa, the maximum limit for an aflatoxin contamination of maize was fixed at 10 \(\upmu\)g kg\({}^{-1}\)[8]. The European Union Commission set the maximum limit of total aflat to 10 \(\upmu\)g kg\({}^{-1}\) for maize intended for sorting and processing, but this limit is 4 \(\upmu\)g kg\({}^{-1}\) when maize is intended for direct consumption [9]. The USA Food and Drugs Administration set, on the other hand, a limit of 20 \(\upmu\)g kg\({}^{-1}\) for the total aflat in maize [10]. A study on the level of exposure of the Ugandan population to aflatoxin showed that the exposure was ubiquitous among the rural population and that this exposure was suspected to be related to the consumption of contaminated food products like _posho_ (also called _ugali_, a stiff porridge made of maize flour) and groundnuts [11; 12]. Aflatoxins are a group of mould metabolites produced by strains of _Aspergillus flavus_ and _Aspergillus parasiticus_[13]. There are four major aflat: B1, B2, G1, and G2, and B1 is the major aflatoxin produced by toxigenic _A. flavus_ strains [14; 15]. _A. flavus_ contamination can occur in the field, as well as during storage, but happens most commonly in storage under favourable conditions. These are the moisture content of the grains, the storage temperature, and the relative humidity in the storage facility all related to the water activity (\(a_{w}\)) [6].