A low-cost, portable device for detecting and sorting aflatoxin-contaminated maize kernels

Authors: YAO, HAIBO - Mississippi State University; ZHU, FENGLE - Mississippi State University; KINCAID, RUSSELL - Mississippi State University; HRUSKA, ZUZANA - Mississippi State University; Rajasekaran, Kanniah - Rajah

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2023
Publication Date: 3/4/2023
Citation: Yao, H., Zhu, F., Kincaid, R., Hruska, Z., Rajasekaran, K. 2023. A low-cost, portable device for detecting and sorting aflatoxin-contaminated maize kernels. Toxins. 15:197. https://doi.org/10.3390/toxins15030197.
DOI: https://doi.org/10.3390/toxins15030197

Interpretive Summary: One persistent worldwide food safety issue associated with corn is aflatoxin contamination due to its carcinogenic nature. The problem becomes more prominent in African countries because of the lack of availability of affordable and feasible methods for small village farmers and consumers to identify aflatoxin-contaminated corn. This paper describes a low-cost, portable, and non-invasive device developed for detection and manual sorting of contaminated corn kernels. The mobile device consisted of an enclosed ultraviolet light source for fluorescence excitation, a tablet for image acquisition, and a software application for detection and visualization. Results from this work show that sorting with the device significantly reduced aflatoxin levels, especially in severely infected and highly contaminated corn kernels. The technology would particularly benefit small village farmers and consumers in developing countries, enabling production of safer food and feed, free of dangerous levels of the highly carcinogenic aflatoxins.

Technical Abstract: Aflatoxin contamination of maize is a major food safety issue worldwide. The problem is of special importance in African countries because maize is one of the staple foods. A major challenge to controlling ingestion of aflatoxin-contaminated food in these countries is the lack of affordable and feasible methods for farmers or consumers in small village farms to identify contaminated maize kernels. This manuscript provides a low-cost, portable, and non-invasive device for detection and sorting contaminated kernels from maize. We developed a prototype to implement a modified, normalized difference fluorescence index (NDFI) detection method to identify maize kernels with potential aflatoxin contamination. The identified kernels can then be manually sorted out to reduce aflatoxin levels. The detection device consisted of an enclosed ultraviolet light source for fluorescence excitation, a tablet for image acquisition, and a software application for detection and visualization. Two experiments, both using maize kernels artificially infected with the toxin-producing Aspergillus flavus 13 (AF13), were carried out to evaluate the performance and the efficiency of the detection device. In the first experiment, we used highly contaminated maize kernels (mean aflatoxin level, 71.18 ppb), and in the second experiment we used mildly contaminated maize kernels (1.22 ppb). The results showed that the combined approach of detection and sorting was effective in reducing aflatoxin levels in maize kernels. With maize rejection rate of 1.02% and 1.34% in the fore-mentioned two experiments, respectively, aflatoxin reduction was achieved at 99.3% and 40.7%. The study demonstrated the potential of using this low-cost and non-invasive fluorescence detection technology followed by manual sorting, to significantly reduce aflatoxin levels in maize kernels . The technology would benefit end users, especially in small village farms and consumers in developing countries, enabling safer food products free of dangerous levels of highly carcinogenic aflatoxins.