Fumonisins: From Technical Cooperation to International Standards

Fumonisins, along with aflatoxins, are the major mycotoxins of international health concern. They are unique among the mycotoxins in being almost exclusively contaminants of maize, particularly when grown in warmer regions. Maize is a major human dietary staple that has been in the diet of Nigeria and the African region for centuries. It started as a subsistence crop and has gradually become a major and the most frequently consumed crop in Nigeria. Fumonisins are also detected in symptomless maize kernels, and surveys of good quality maize and maize based products have revealed the natural presence of fumonisins at very low levels.

From FAO Maize Post-Harvest Operation Because of concerns about mycotoxin contamination in the food and feed supply in developing countries, the International Atomic Energy Agency (IAEA) Technical Cooperation (TC) Department, in collaboration with the Food and Environmental Protection Subprogramme of the Joint FAO/IAEA Joint Division of Nuclear Techniques in Food and Agriculture, developed a number of international capacity building projects aimed at the establishment of analytical infrastructures to monitor import/export agricultural products for consumer health protection and to support food trade between member states. Within the framework of the IAEA TC Project NIR/5/030 entitled Regulatory Control and Monitoring of Contaminants and Residues in Fresh Produce, staff members from the National Agency for Food and Drug Administration and Control (NAFDAC, Nigeria) were trained on the use of analytical methodologies to detect, monitor and control fumonisins in maize.

Project Summary

Symptoms of Fusarium ear rot, Alison Robertson, Integrated Crop Management News and Iowa State University Extension Under the TC Project NIR/5/030, a study was designed to assess the incidence and contamination levels of fumonisin B1 in maize samples marketed in five geographical locations in Nigeria. Maize kernel samples were purchased from markets, retail outlets, and cereal stores in Lagos, Ibadan, Maiduguri, Kaduna, and Enugu. The samples were identified by location and lot number and sent to the Food and Environmental Protection Laboratory in Seibersdorf, Austria for analysis. Each lot was tested for fumonisin B1 (FB1) by an HPLC method using pre-column derivatization/fluorescence detection.

The limit of quantitation (lowest calibrated level) of the analytical method was 0.01µg/g for FB1. The FB1 concentration among the eighty-seven lots marketed in Nigeria varied from a low of 0.01µg/g to a high of 2.98µg/g with an average of 0.91µg/g. While all eighty-seven lots were contaminated with FB1, the overall results indicated that relatively low levels were encountered in the lots tested in Nigeria. Twenty-eight percent of the eighty-seven lots tested less than 0.50µg/g and 67.8% contained concentrations of FB1 less than 1.0µg/g.

Project Results and Conclusions

The study indicated that fumonisin B1 is a widespread contaminant of maize kernels in Nigeria. Various contamination levels were encountered across the five different areas and the overall results revealed relatively low levels of contamination. These findings were consistent with results reported worldwide confirming the widespread presence of the fumonisins in maize, and demonstrate the potential risk of chronic exposure of the consumer to fumonisin, especially through the ingestion of poor food quality grade grain.

Since maize has become Africa’s most important staple food crop, being consumed up to three times a day and used as weaning food for babies, the enforcement of good agricultural practices, including the disposal of visibly damaged kernels through cleaning procedures and wet food processing, is strongly recommended to reduce the fumonisin B1 content, thus preventing exposure of consumers to harmful toxins in food.

International Standards

These research findings were presented to the 3rd Session of the Codex Committee on Contaminants in Foods (CCCF), (Rotterdam, the Netherlands, 23-27 March 2009), at which the CCCF agreed to initiate work on establishing maximum levels. In discussing the potential establishment of proposed draft maximum levels in maize and maize products and associated sampling plans at the subsequent 4th Session of the CCCF (Izmir, Turkey, 26-30 April 2010), the Committee noted that fumonisins in maize and maize products were proposed for evaluation by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and therefore, the Committee agreed to suspend work on the establishment of maximum levels until the completion of the JECFA evaluation. The JECFA assigned a high priority to the evaluation of fumonisins, including the consideration of occurrence data generated and submitted by Nigeria under TC Project NIR/5/030.

Further information

Joint FAO/WHO Food Standards Programme, Report of the Fourth Session of the Codex Committee on Contaminants in Foods (ALINORM 10/33/41), Izmir, Turkey, 26-30 April 2010. Proposed Draft Maximum Levels for Fumonisins in Maize and Maize Products and Associated Sampling Plans (CX/CF 10/4/8) and Comments Submitted at Step 3 by Egypt, the European Union, Ghana, Japan, Kenya, Norway, the Philippines, Thailand, COCERAL and the IAEA (CX/CF 10/4/8 - Add. 1).