~ 2895 ~ Journal of Pharmacognosy and Phytochemistry 2019; 8(4): 2895-2906 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2019; 8(4): 2895-2906 Received: 13-05-2019 Accepted: 15-06-2019 SK Singh Main Maize Research Station, Anand Agricultural University, Godhra, Panchmahals, Gujarat, India MB Patel Main Maize Research Station, Anand Agricultural University, Godhra, Panchmahals, Gujarat, India BN Thakker Main Maize Research Station, Anand Agricultural University, Godhra, Panchmahals, Gujarat, India AJ Barad Main Maize Research Station, Anand Agricultural University, Godhra, Panchmahals, Gujarat, India Robin Gogoi Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, Pusa Campus, New Delhi, India KS Hooda ICAR-Indian Instutie of Maize Research, PAU Campus, Ludhiana, Punjab, India Correspondence SK Singh Main Maize Research Station, Anand Agricultural University, Godhra, Panchmahals, Gujarat, India An overview of challenges and elimination of aflatoxin contamination in maize ( Zea mays ) SK Singh, MB Patel, BN Thakker, AJ Barad, Robin Gogoi and KS Hooda Abstract Maize is an important cereal crop for domestic markets as well as for foreign trade in several developing and developed countries. It is also one of the most valuable cash crops in India. However, its production is constrained by Aspergillus species, which cause quantitative losses and produce highly toxic and carcinogenic chemical substances known as aflatoxins. This article critically reviews Aflatoxin contamination in maize (Zea mays L.) in India and its elimination. Although maize has a huge potential as a cash crop to improve livelihoods of farmers and traders in various parts of India, its market is declining and export of the crop has come to a standstill. This is due to aflatoxin contamination of the crop and the difficulty of meeting tolerance limits by importers and food processors, leading to rejection of the crop and reduction in market demand. Aflatoxin contamination is both a pre-harvest and post- harvest problem. Many developed countries have laid down specific regulations for import and export of those items in terms of economic implications. In the light of present status different measures (prevention, elimination, and decontamination/inactivation) have been discussed in this review to minimize the risk of aflatoxin contamination in pre-harvest, harvest, post-harvest, processing stage and storage conditions. Keywords: Aflatoxin, Zea mays, Aspergillus flavus, maize, toxin 1. Introduction Maize plays an important role in the livelihoods of poor peoples and in the rural economy of many developing countries. Aspergillus flavus is a fungus of economic and toxicological importance due to the production of aflatoxins and other chemicals with deleterious properties (e.g., aspergillic acid, cyclopiazonic acid, kojic acid, helvulic acid, etc.). This fungus is ubiquitous in the environment, being readily isolated from plants, air, soil, and insects (Wicklow et al., 2003, Matthew et al., 2017) [113, 78] . Aflatoxins are cancerous secondary metabolites produced primarily by Aspergillus flavus and Aspergillus parasiticus in agricultural foodstuff such as maize, peanuts grains, cereals, and animal feeds. Aflatoxins are difuranocoumarin molecules synthesized through the polyketide pathway (Bennett and Klich, 2003) [16] . Six out of 18 different types of aflatoxins that have been identified are considered important and are designated as B1, B2, G1, G2, M1, and M2, respectively (Dors et al., 2011) [40] . These aflatoxin groups exhibit molecular differences. For example, the B-group aflatoxins (B1 and B2) have a cyclopentane ring while the G-group (G1 and G2) contains the lactone ring (Gourama and Bullerman, 1995) [52] . Whereas the B-group aflatoxins exhibit blue fluorescence, the G-group exhibits yellow-green fluorescence under ultraviolet (UV) light, thus making the use of fluorescence important in identifying and differentiating between the B and G groups. Aflatoxin B1 is the most common (Hussein and Brasel, 2001) [65] and the most widespread (Cullen et al., 1993; Kok, 1994) [32, 72] in the world and accounts for 75% of all aflatoxins contamination of food and feeds (Ayub and Sachan, 1997) [7] . Aflatoxins M1 and M2 are hydroxylated products of aflatoxins B1 and B2, respectively, and are associated with cow milk upon ingestion of B1 and B2 aflatoxins contaminated feed. Moreover, once formed from B1 and B2 forms, aflatoxins M1 and M2 remain stable during milk processing (Stroka and Anklam, 2002) [104] . Aflatoxins are a group of chemicals produced by certain mould fungi. These fungi, Aspergillus flavus and Aspergillus parasiticus can be recognized by olive green or graygreen, respectively, on maize kernels, in the field or in storage (Fig. 1). Although aflatoxins are not automatically produced whenever grain becomes mouldy, the risk of aflatoxin contamination is greater in damaged, mouldy maize than in maize with little mould. Aflatoxins are harmful or fatal to livestock and are considered carcinogenic (cancer causing) to animals and humans. In the midwest, aflatoxin levels are highest during hot, dry summers. The prime conditions for the fungus to produce toxin are warm (>70°F) nights during the later stages of grain fill (August/