History of Aflatoxin Agent First Studied as a Potential Food Safety Hazard

Introduction to Turkey X Disease

It was during 1960 when 100,000 turkeys in England started getting sick and dying; the disease was diagnosed as Turkey X disease. It was soon discovered that not only turkeys, but also ducklings and young pheasants were affected, experiencing a high mortality rate. Investigations revealed that the vector of the disease was groundnuts imported from Brazil. With intense effort, the causative agent was identified as a species of mold called Aspergillus flavus. This mold secretes a hepatotoxic product, which was recognized as a major toxin, and thus, aflatoxins were brought into the spotlight. The discovery that aflatoxins were carcinogenic and immunosuppressive raised significant concerns about their occurrence in human and animal foods and feeds, respectively.

The Mycotoxin Gold Rush

The years between 1960 and 1975 have been labeled as the “mycotoxin gold rush” because many chemical prospectors were involved in the search for mycotoxins. It was gradually discovered that aflatoxin contamination could occur not only due to poor storage but also before harvesting and during food processing. Major crops such as peanuts, figs, corn, cereals, rice, etc., were categorized as high-risk foods for this toxin. This revelation emphasized the need for stringent food safety measures to prevent aflatoxin contamination at various stages of food production and storage.

Classification and Evaluation of Aflatoxins

The major aflatoxins were classified as B1, B2, G1, and G2 based on their fluorescence activity under ultraviolet light and mobility in thin-layer chromatography. Aflatoxin B1 is the most toxic and occurs at the highest levels. Due to high concerns about aflatoxins being carcinogenic, the Joint FAO/World Health Organization (WHO) Expert Committee on Food Additives (JECFA) evaluated aflatoxin in 1987 during its thirty-first meeting and attempted to determine the potential dose (JECFA, 1987). However, due to the uncertainty of the data, the committee could not establish a definitive exposure dose of aflatoxin for liver cancer. In 1994, during the twenty-sixth meeting of the Codex Committee on Food Additives and Contaminants (CCFAC), JECFA was asked to provide estimates on aflatoxin potency. In response to this request, JECFA, during their forty-ninth meeting in 1997, issued conclusions regarding aflatoxin risk assessment (JECFA, 1997).

Conclusions on Aflatoxin Risk Assessment

• Aflatoxins are considered carcinogenic to human livers, with B1 being the most potent.
• The potency of aflatoxins in individuals carrying hepatitis B is high. Thus, reducing the intake of a diet potentially contaminated by aflatoxins will lower the risk of liver cancer for such high-risk populations.
• Vaccination against hepatitis B will reduce the risk of liver cancer from exposure to aflatoxins.
• Two different hypothetical standards regarding dose were studied for aflatoxin contamination: one is 10 mg per kilogram, and the other is 20 mg per kilogram.
• Populations with low risk of hepatitis B surface antigen and average low intake of aflatoxins (less than 1 ng per kilogram of body weight per day) are unlikely to show major differences in population risks. Conversely, populations in which hepatitis B surface antigen is positive and the intake of aflatoxin-contaminated diet is high would benefit from reductions in aflatoxin intake.

Strategies for Reducing Aflatoxin Intake

Aflatoxin intake can be reduced through improved farming practices, proper storage, and establishing standards for feed and food within countries and across borders. Implementing these strategies can significantly mitigate the risks associated with aflatoxin contamination, thereby safeguarding public health and ensuring food safety on a global scale.

References

JECFA. (1987). Evaluation of certain food additives and contaminants. World Health Organization Technical Report Series, No. 759.

JECFA. (1997). Evaluation of certain food additives and contaminants. World Health Organization Technical Report Series, No. 884.