Aflatoxin B1 Occurrence

**3**

**Chapter 1**

in Kenya

**Abstract**

*and Dora A.O. Orony*

Aflatoxin B1: Chemistry,

*Joseph Owuor Lalah, Solomon Omwoma* 

health risks of AFB1 in Kenya are discussed.

health risks, Kenya

**1. AFB1 chemistry**

**Keywords:** aflatoxin B1, chemistry, determination, toxicity, exposure,

The aflatoxins were discovered in a toxic peanut meal after causing 'turkey X' disease, which killed large numbers of turkey poults, ducks, young pheasants and chicks in the UK in the early 1960s [1], and more than 100,000 young turkeys in poultry farms were killed [2]. The peanut meal was highly toxic, and the toxin-producing fungi was identified as *Aspergillus flavus* hence the name of the toxin, aflatoxin [2]. Extracts of the feed later induced the now known toxic symptoms in experimental animals, and purified metabolites with properties identical to aflatoxins B1 and G1 (AFB1 and AFG1) were later isolated from the *Aspergillus flavus* cultures [1, 3, 4]. Structural elucidation of aflatoxins was accomplished and confirmed by total synthesis in 1963 [4]. There are four major aflatoxins B1, B2, G1 and G2 plus two additional toxic metabolic products M1 and M2 that are of significance as direct contaminants of foods and feeds and whose structures have been elucidated [3, 4].

Environmental and Diet Sources

and Potential Exposure in Human

Cancer incidences and mortality in Kenya are increasing according to recent reports and now number among the top five causes of mortality in the country. The risk factors responsible for this increase in cancer incidences are assumed to be genetic and/or environmental in nature. The environmental factors include exposure to carcinogenic contaminants such aflatoxins (AFs). However, the exact causes of the increase in cancer incidences and prevalence in many developing countries are not fully known. Aflatoxins are known contaminants produced by the common fungi *Aspergillus flavus* and the closely related *Aspergillus parasiticus* which grow as moulds in human foods. Aflatoxin B1 (AFB1) is most common in food and is 1000 times more potent when compared with benzo(a)pyrene, the most potent carcinogenic polycyclic aromatic hydrocarbon (PAH). Aflatoxins have therefore drawn a lot of interest in research from food safety and human health point of view. In this chapter, the chemistry, synthesis, identification, toxicology and potential human
