Assessment of aflatoxin contamination and aflatoxigenic fungi in imported rice, peanut and tree nuts

Aflatoxins are a group of carcinogenic metabolites produced mainly by Aspergillus flavus and A. parasiticus that often contaminate various agricultural commodities. Aflatoxins can be detected in maize, peanut, chilli, wheat, rice, sorghum, cottonseed, almonds, pistachios, Brazil nuts, walnuts, copra and figs as a result of fungal contamination before and after harvest. Currently 18 different types of aflatoxins have been identified among which aflatoxin B1, B2, G1 and G2 (AFB1, AFB2, AFG1 and AFG2) are frequently occurring in food. Aflatoxin M1 (AFM1) is the hydroxylated metabolite of AFB1, which is found in milk and dairy products derived from dairy cattle that have consumed AFB1- contaminated feed. Aflatoxins are highly stable molecules which are extremely difficult to remove or destroy once produced in an agricultural commodity. Ingestion of aflatoxin contaminated diet leads to the disease called ?aflatoxicosis? in humans, poultry birds and livestock. Aflatoxicosis is recognized as the sixth amongst the 10 most important health risks identified by World Health Organization. Exposure of people to a high level of aflatoxins through food is a serious threat to public health. Human dietary exposure to aflatoxins, especially from potentially rich sources such as peanuts, maize, almonds, pistachios, Brazil nuts, walnuts and rice, can be minimized by implementation of the principle of As Low As Reasonably Achievable (ALARA). Oman imports various agricultural products from other countries. However, studies on the levels of aflatoxins in foods in Oman are limited. In the proposed study imported rice, peanuts, almonds, pistachios, Brazil nuts and walnuts samples will be collected from the Plant Quarantine Department, Ministry of Agriculture and Fisheries, retail shops and super markets in Muscat and analyzed for aflatoxins in order to understand the magnitude of aflatoxin contamination. Information on daily consumption rate of rice, peanut and tree nuts and body weight of consumers will be collected by conducting survey by issuing questionnaires and aflatoxin exposure risks from imported agricultural products will be assessed based on margin of exposure (MOE) as a model. Furthermore, the toxigenic fungi associated with the aflatoxin-contaminated samples will be identified by using molecular techniques. This study will provide the basic understanding of the extent of aflatoxin contamination and prevalence of toxin producing fungi in the imported high-risk agricultural products. Such information will be helpful for the Ministry of Agriculture and Fisheries, Regional Municipalities and Muscat Municipality for risk assessment and to impose appropriate quarantine regulations in the country.