Aflatoxin mold

Most foods are not entirely safe, and I am including natural foods in this category. There are toxic chemicals in some foods, such as aflatoxin mold that grows on contaminated peanuts and causes liver cancer. Overuse of ordinary table sugar has been correlated with breast cancer. Overuse of high-fat, high-cholesterol foods increases the risk of heart disease, the number one cause of death in our country. Cancer researchers claim that as much as 30 percent of all cancers are diet related, and almost every food carries some level of carcinogens. 

Foods high ia sucrose, proteia, or starch (qv) tend to biad water less firmly and must be dried to a low moisture content to obtain microbial StabiHty. For example, grain and wheat flour can support mold growth at moisture contents above 15% (wet basis) and thus are stored at moisture contents below 14%. Stored grains and oil seeds must be kept at a water activity below 0.65 because certain molds can release aflatoxias as they grow. Aflatoxins are potent carciaogens (see Food toxicants, naturally occurring). 

Aflatoxin Bi (AFB) is a mold metabolite which has been observed to be acutely toxic and carcinogenic to a wide variety of animals (5,6) and has been implicated in human primary hepatic carcinoma (7, 8). Diets deficient in protein have been reported to increase the susceptibility of mammals to acute AFB toxicity and the induction of cancer (2, 9, 10, 11, 12, 13). Increased dietary proteins have increased the carcinogenic activity of AFB fed to rats (1 4) and trout (15.). Supportive of this latter finding has been the reported direct relationship between dietary protein content and AFB-DNA adduct formation in vivo in rats (16, 17). 

Of course the chemists creating organic compounds are living (most of them anyway), but the compounds are created in laboratory flasks without the assistance of living organisms. Such synthesis is clearly different from, for example, the production of colors by flowers and aflatoxins by molds. 

DETAILS - Aflatoxins are the poisonous product of a group of polynuclear molds that grow on peanuts, com and in cottonseed meal. They are responsible for the Turkey X" disease which occasionally devastates the poultry industry. The presence of the mold doesn t always indicate presence of the toxin. Toxin production is dependent on various factors such as moisture and temperature. There are two basic types of aflatoxins, both of which are fluorescent under UV (black) light. Once the mold has been identified, the UVI ight is an excellent way to check for toxin production. Aflatoxin B glows blue, while Aflatoxm G glows... 

Aflatoxins are potent carcinogenic, mutagenic and teratogenic metabolites produced by molds. The major food affected with aflatoxins are corn, peanuts, rice, cottonseeds, dried fruit and milk from ingestion (103). The US action standards established by FDA are 20 pg/Kg for foods consumed by humans and 0.5 pg/kg for milk. In the case of animal feed, the levels are from 100 to 300 pg/kg. Therefore, assays capable of detecting at these levels have to be developed, (see Table 1 (104,105)). Detection of aflatoxins entails conjugation of these small molecules with carrier proteins like bovine serum albumin to produce antibodies (20). A number of commercial kits for aflatoxins are available (see sections on kits and immunoaflinity purification). 

Molds that grow on nuts (especially peanuts) create aflatoxins, substances that cause liver cancer... 

The most common source of aflatoxins is moldy food, particularly nuts, some cereal grains, and oil seeds. The most notorious of the aflatoxins is aflatoxin B1( for which the structural formula is shown in Figure 19.1. Produced by Aspergillus niger, it is a potent liver toxin and liver carcinogen in some species. It is metabolized in the liver to an epoxide (see Section 7.3). The product is electrophilic with a strong tendency to bond covalently to protein, DNA, and RNA. Other common aflatoxins produced by molds are those designated by the letters B2, G1( G2, and M,. 

Coumarin synthesis. The Pschorr coumarin synthesis involves the reaction of phenols with -keto esters in the presence of a condensing agent (usually sulfuric acid). In a synthesis of the coumarin mold metabolite aflatoxin M, (3), Biichi and Weinreb found that the usual conditions could not be employed because the phenol (I) is exceptionally sensitive to acidic reagents. However, they effected the desired condensation of... 

Figure 27.45. Aflatoxin Reaction. The compound, produced by molds that grow on peanuts, is activated by cytochrome P450 to form a highly reactive species that modifies bases such as guanine in DNA, leading to mutations.

The first poison to be isolated from a mold is afla-toxin. This and other poisonous substances produced by molds and other fungi are referred to as mycotoxins. Some mycotoxins are deadly to humans in tiny doses, others will only affect certain animals. Aflatoxin was first isolated in 1960 in Great Britain. It was produced by Aspergillus flavus that had been growing on peanuts. In that year, aflatoxin had been responsible for the death of 100,000 turkeys. In fact, it was the massive financial loss from these deaths that led to the research that discovered aflatoxin. 

From the beginning of the twentieth century, scientists had tentatively linked a number of diseases with molds, but had not been able to isolate the compounds responsible. With the discovery of aflatoxin, scientists were able to provide proof of the undesirable effects of a mold. 

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