**2.4. Determination of moisture content**

The moisture content of groundnut samples was measured using the Mini GAC moisture meters. These were calibrated to ensure the accuracy. To determine the moisture content, groundnut samples were initially shelled. Later, a total of 50 g was filled in the moisture meter loader, after which the loader was emptied into the analyzer. The results were read using the display window on the moisture meters.

#### **2.5. Aflatoxin analysis**

#### *2.5.1. Validation of the MReader*

To determine the precision and recovery of the immune-chromatographic assay analysis, antigenic standards were used. For high calibration standard procedure, 100 μl of pink antigenic standard was added to 500 μl of sample buffer diluent. Then 100 μl was aliquoted in a separate vial. A reveal Q+ test strip was placed in the vial and was left to develop for 6 min. After 6 min, the strip was placed in the mreader strip holder, and the aflatoxin levels were read using the mreader. For the low calibration standard procedure, 35 ml of 65% ethanol solution was added to a 10 g control groundnut sample which was free of aflatoxins. Then, a 100 μl of the pink antigenic standard solution was added to the 30 ml extracts and mixed for 2 min. Later, a 100 μl of the mixture was added to 500 μl of the sample buffer diluent. A mixture of 100 μl was later aliquoted to a separate vial. Finally, the total aflatoxin in the sample was measured by placing the reveal Q+ test strip in the vial and was left to develop for 6 min, and aflatoxin reading was done using the mreader.
