Aflatoxins Aflatoxin

Humans are also exposed to the aflatoxins when consuming animal products that were contaminated because the animal ate feed containing aflatoxin. Aflatoxin contamination can be passed to milk and dairy products as aflatoxin M (Figure 9.1). 

Aflatoxin B, see Aflatoxins) Aflatoxin B2 see Aflatoxins) Aflatoxin Gj see Aflatoxins) Aflatoxin G2 see Aflatoxins) Aflatoxin Mj see Aflatoxins) Agaritine Alcohol drinking Aldicarb Aldrin... 

We can bring together a lot of these points in the structure of one compound, the dreaded aflatoxin. Aflatoxin B] is an example. 

Aflatoxin Bi (9.15, Scheme 9.1) is one of the most potent carcinogens known. There is a significant relationship between the presence of aflatoxins in the diet and the incidence of liver cancer. The reactive enol ether of aflatoxin Bi is epoxidized in the liver to form the active metabolite which may react with DNA. The adduct 2-(7V-7-guanyl)-3-hydroxyaflatoxin Bi (9.18) has been detected in the urine of test animals fed aflatoxin. Aflatoxin Bi is also hydroxylated by animals that have ingested it in their fodder. A carcinogenic metabolite, aflatoxin Mi (9.16), has been identified in the milk of these animals. 

More than 350 mycotoxins have been identified either from food or from laboratory culture media. The main mycotoxins (Table 1) of concern for the safety of consumers are aflatoxins (aflatoxins B and G, aflatoxin Ml), ochratoxin A, patulin, fumonisins, zearalenone, and deoxynivalenol (DON) and other... 

Fig. P-44. Sporulation of Aspergillus flavus on a kernel of corn. This fungus produces aflatoxin. Aflatoxin (1) is associated with a high indicence of liver cancer, and (2) may be involved in some types of acute poisoning of children. (Courtesy, C. W. Hesseltine, USDA, Agricultural Research, Peoria, III.)...

Of the several aflatoxins, aflatoxin Bi (AFBi) is the most prevalent and the most potent. AFBj is converted to an unstable metabolite (the 8,9-epoxide), is highly electrophilic, and forms covalent adducts with RNA, DNA, and proteins (Roebuck and Maxuitenko, 1994). In addition, aflatoxin Mi, a metabolite of AFBi, has been found in the milk of cows fed AFBi. 

Product Positive/Total sample A. flavus Aflatoxin Aflatoxin (ng/g) 1 2 1 ... 

One of the chemicals that tested positive in the Ames test is aflatoxin. Aflatoxin is a natural toxin produced by a fungus that grows on some food crops (e.g., peanuts) during storage in warm, moist locations. Aflatoxin had an extremely strong response in this test, which along with results in whole animal tests conclusively led to the identification of aflatoxin as a human carcinogen. Based on these tests, aflatoxin levels are monitored and must be at extremely low levels for the produce to be released to consumers. 

FIGURE 6.3 Chemical structure of the different types of aflatoxins. Aflatoxins B and G occur in infested grains, whereas M aflatoxins are found in the milk of lactating animals fed contaminated feedstuffs. 

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