Aflatoxin in peanut butter: MRC policy brief

PROMEC Unit, Medical Research Council, PO Box 19070, Tygerberg, 7505 South Africa; tel. (021) 938-0290.

During May 2001 several reports appeared in the news media in South Africa about the "poison in the peanuts". These related to high levels of aflatoxin that were allegedly found in peanut butter given to school children in the Eastern Cape under the Primary Schools Nutrition Programme (PSNP). The PROMEC Unit of the South African Medical Research Council (MRC), an internationally recognised centre of excellence on toxins produced by fungi (mycotoxins), including aflatoxin, decided to prepare this Policy Brief in order to clarify the issue and to emphasise the serious health implications of supplementing the diet of school children with peanut butter containing aflatoxin. Staff members of the PROMEC Unit are regularly invited to be expert consultants on food-borne toxins by the World Health Organization (WHO) and the Food and Agriculture Organisation of the United Nations (FAO). Unfortunately they were not consulted by the South African Department of Health (DOH) when the PSNP, including peanut butter, was launched in 1994.

In fact, the PROMEC Unit first became aware of concerns about the presence of aflatoxin in peanut butter used in the PSNP in February 1998 from consultants to and representatives of the Western Cape Department of Health (WCDOH). Since then the PROMEC Unit has, on various occasions, held meetings with representatives of WCDOH, peanut butter manufacturers and distributors, and the Peninsula School Feeding Association about the occurrence and source of aflatoxins in peanut butter, and problems in sampling and analysis of contaminated foods and health implications. It transpired from these meetings that limited budgets and personnel did not allow for adequate sampling and chemical analyses. Although no funds were available for an expert investigation to be undertaken by the PROMEC Unit, staff members presented several lectures to health authorities about the risk of exposing school children to aflatoxin.

Mycotoxins (of which aflatoxin is an example) are a group of secondary metabolites produced by fungi that are natural contaminants of agricultural products such as peanuts. The toxicological effects in animals have been known for a long time and have necessitated health authorities worldwide to regulate mycotoxin levels in human food and animal feed. The presence of mycotoxins in food is, however, often overlooked due to public ignorance about their existence; lack of regulatory mechanisms; dumping of food products in developing countries; and the introduction of contaminated commodities into the human food chain during chronic food shortages due to droughts, wars, political and economic instability, etc. Apart from economic issues, ethical considerations also play a role during the manufacturing process of food products using heavily contaminated commodities. Instead of excluding these from the food process, unscrupulous manufacturers sometimes dilute contaminated agricultural products such as peanuts with good-quality products to an ‘acceptable' level below the regulatory level, or market them as such when no regulatory measures are enforced. Aflatoxins, of which aflatoxin B1 (AFB1) is the most important, are produced mainly by the fungus Aspergillus flavus, that may grow on peanuts before or after harvesting and under poor storage conditions.

In 1993 the International Agency for Research on Cancer (IARC) classified AFB1 and mixtures of aflatoxins as Group 1 carcinogens, i.e. substances that can cause cancer in humans. Epidemiological studies of human populations exposed to diets naturally contaminated with aflatoxins revealed an association between the high incidence of liver cancer in Africa and elsewhere and dietary intake of aflatoxins.  The tolerance levels of aflatoxins in human foodstuffs are regulated worldwide and in South Africa by Government Notice No. R 313 of 16 February 1990, Regulations Governing Tolerances for Fungus-Produced Toxins in Foodstuffs. According to these regulations, which are the responsibility of the DOH, the maximum legal level of total aflatoxins in foodstuffs is 10 micrograms per kilogram, of which 5 micrograms per kilogram (parts per billion) may be AFB1. According to several newspaper reports, levels of 271,63 micrograms per kilogram of total aflatoxin and 165,05 micrograms per kilogram AFB1 were reported in peanut butter given to school children in the Eastern Cape. These levels are approximately 30 times higher than the legal limits. 

At present it is not known how these aflatoxin levels were determined and whether standardised sampling procedures and chemical analytical techniques were applied. No data are available for the other provinces, but it can only be assumed that the problem is not restricted to the Eastern Cape but occurs everywhere in South Africa where the PSNP is operational. The question arises whether the DOH considered the health aspects of aflatoxins in peanut butter at the onset of the PSNP, or whether sufficient funds were allocated to enforce adequate sampling and testing to safeguard a commodity intended to supplement the diet of underprivileged school children. Newspaper reports indicate that 4,8 million children are involved in the PSNP throughout South Africa, and that R472,8 million was allocated on the inception of the programme. The media further indicated that the Nutrition Deputy Director of the Eastern Cape allegedly "challenged anyone with information about illnesses caused by the peanut butter to come forward". If this is quoted correctly, it is a most unfortunate statement as this is not the issue here. Health implications of exposure to aflatoxins can be divided into symptoms of acute poisoning (aflatoxicosis) and chronic long-term health effects.

Although aflatoxins have been implicated in several episodes of acute human aflatoxicosis in various areas of the world, these have been reported at contamination levels in the milligrams per kilogram (parts per million) range, i.e. 1000 times higher than the legal tolerance levels. However, the major health implication and area of considerable international concern with respect to aflatoxin exposure is the cancer-causing (carcinogenic) properties of AFB1, in that long-term exposure to low levels of the toxin may cause liver cancer. This is the reason why aflatoxins are the most widely and severely regulated of all the mycotoxins. It is of great concern that the liver cancer risk increases significantly if a child suffering from hepatitis B virus (HBV) infection consumes aflatoxin-containing foodstuffs, due to the synergism between AFB1 and HBV in causing liver cancer. The PSNP was launched in 1994, and in areas with poor control over tender specifications and inadequate enforcement of legal levels of aflatoxins in peanut butter during the past 7 years, may have increased the liver cancer risk in millions of previously disadvantaged school children. The risk may have been increased markedly if the children consumed the high levels of aflatoxins quoted in the news media, and particularly if they are carriers and/or subsequently become infected with HBV. An increase in liver cancer incidence in South Africa within 20 to 30 years from now is therefore possible.


If the provision of peanut butter sandwiches as an important nutritional supplement for school children is to continue, rigorous quality control measures need to be enforced by DOH on the manufacturers and distributors.  Adequate funding should be made available for surveillance by local health authorities to ensure that suppliers comply with existing legislation aimed at reducing the risk of exposure to aflatoxins.  Cancelling Atoxic peanut butter contracts@ and/or appointing new manufacturers or "consultants" who know nothing about the aflatoxins will not solve the problem. Aflatoxin contamination of peanuts and peanut butter can only be controlled if constant vigilance is exercised by manufacturers and health authorities and when appropriate sampling procedures and standardised chemical analytical techniques are used. These analyses should be carried out with an expert mycotoxin group such as the PROMEC Unit of the MRC as an independent and objective consultant.  Closer collaboration and communication between the DOH, PSNP, MRC and the PROMEC Unit is essential to prevent a catastrophe such as the "poison in the peanuts" from ever happening again.  Food safety is one of the democratic rights of a healthy nation and should be fostered at all costs.

Note: We would like to point out that the peanut butter used in the PSNP is quite different from commercially available peanut butter, most of which is regularly monitored for aflatoxin levels in South Africa. - MRC News


August 2001