Mini Aflatoxin Sorter

The Mini Aflatoxin Sorter (MAF-Sorter) uses a patented spectral imaging technology for fast and easy detection and manual sorting of maize contaminated with aflatoxin. The MAF-Sorter is the only rapid, low-cost, portable and easy to use method for farm families in SSA to screen and sort household lots of maize for aflatoxin contamination. In trials with the original prototype of the MAF-Sorter with US corn (2014-17), results showed reductions of 89-99% of the aflatoxin contamination in maize batches (with a rejection rate of less than 1.5% of total maize).

The MAF-Sorter consists of an Android tablet with camera, UV filter, high intensity, narrow bandwidth UV LED light array, rechargeable battery, and software app – all housed in a lightweight, portable sorting box, for simple, rapid batch screening and manual sorting of maize. The app performs image acquisition and detection functions, including an augmented reality function that overlays red marks on the contaminated kernels for the user to quickly see and remove. Aflatoxin contamination in maize is not easily detected under normal light; but under high intensity, narrow bandwidth 365 nm UV light a contaminated kernel reflects a distinct bright green-yellow fluorescence (BGYF), different from the blue fluorescence of a healthy kernel. A tablet camera is faster and more effective at detecting BGYF kernels than the human eye, which has very low sensitivity at shorter wavelengths.

The MAF-Sorter weighs about 3 lbs and is about the size of a small microwave. It  enables the user to sort approximately 24 kg/hour (in 0.2 kg batches of shelled maize; 30 seconds/batch). After drying and shelling (prior to milling) batch sorting can be done in a similar lot size as household milling. In 1-2 hours, the average SSA farm household can screen and sort all the maize needed for the week. For shelled maize not immediately milled, removing the contaminated kernels can also reduce the risk of mold and aflatoxin contamination spreading in storage. Since contaminated kernels are often not uniformly spread throughout a lot, even with chemical tests, biological controls, and post-harvest dryers, comprehensive post-harvest screening and sorting of entire lots of maize is needed to find and remove any potentially dangerous kernels prior to consumption (a common practice for many foods around the world).

Maize Box Program

The Maize Box Program will distribute MAF-Sorters through existing maternal/infant/child health programs and agriculture/food security programs in SSA, since the device supports health and post-harvest farming objectives, and there is overlap in the target audience given women's role in agriculture. Because the MAF-Sorter is lightweight and portable, and only requires a couple hours of use per week by a family, it is eminently sharable at the village level, among groups of mothers and expectant mothers in a village-based health group, farming group, church, mosque, etc. It is not uncommon for women in a village to work together on the task of milling, so co-ownership and sharing of the MAF-Sorter may complement existing practices.

The Maize Box Program's plan to subsidize the MAF-Sorter as preventive care for mothers, infants and young children is based on Finland's longstanding baby box program, which provides a free maternity package to all expectant mothers to help promote early childhood health. When the program began (1930s) Finland was a poor country, and infant mortality was high, 65 out of 1000 babies died.[1] Today the rate is 1.9 per 1000 in Finland; it is 51.5 per 1000 in SSA.[2]

[1] Lee, Helena. (June 4, 2013). 'Why Finnish babies sleep in cardboard boxes.' BBC News.

[2] The World Bank. World Bank Open Data.


Ears of corn under high intensity, 365 nm UV light. Contaminated kernels reflect a bright green-yellow fluorescence, different from the blue fluorescence of healthy kernels.


Mini Aflatoxin Sorter (prototype) with canvas cover.


Tray of kernels under high intensity UV light with MAF-Sorter tablet, using augmented reality feature to mark kernels in red that are suspected of aflatoxin infection.


MAF-Sorter tablet live feed of a tray of kernels under ordinary light with augmented reality feature marking suspicious kernels in red for easy detection and real-time manual sorting.