Aflatoxins toxicity

Toxic compounds polychlorinated biphenyls, polycyclic aromatic hydrocarbons, organochlorine pesticides, chlorinated pesticides, dioxins, veterinary drug residues, hormone residues, aflatoxins, toxic compounds in shellfish. Compoimds of nutritional significance in foods vitamins, fat, lipids, carbohydrates, protein, energy-calorific value, proximates, dietary fibre, ash. Other compounds hormones in blood serum... 

Netke SP, Roomi MW, Tsao C, Niedzwiecki A Ascorbic acid protects guinea pigs from acute aflatoxin toxicity. Toxicol Appl Pharmacol 1997 143 429—435. 

Acute aflatoxin toxicity should be treated with decontamination procedures and good supportive care. With chronic ingestions, the primary treatment remains supportive in nature. Elevation of serum alkaline phosphatase is a good indicator of aflatoxin toxicity. 

Aflatoxins—toxic metabolites from molds (Figure 7.9)... 

Laboratory investigations in a number of animal species have confirmed that aflatoxins can produce acute necrosis, cirrhosis and carcinoma of the liver. No animal species has been shown to be refractory to aflatoxin toxicity, however, a wide range of acute lethal doses have been observed, indicating different degrees of acute susceptibility. For most species the doses that killed 50% of the animals treated ranged from 0.5 to 10 mg/kg body weight. Species differ in their susceptibility to the acute and chronic effects, and toxicity can be influenced by dose, duration of exposure, age, health, nutritional status and environmental factors. 

Contamination by aflatoxins, toxic compounds produced by fungi that grow in grains, nuts, and other products, has... 

In summary, our observations that many structurally different thiols can suppress the mutagenic activity of aflatoxin B. suggest that thiols may be useful for inactivating aflatoxins in contaminated foods, as an,antidote to treat cases of aflatoxin toxicity, or for prophylaxis to prevent aflatoxin poisoning. 

Dashek, W.V., and Llewellyn, G.C. (1977). Aflatoxin toxicity and mode of action in plant tissues. Extrait de Annales de la Nutriton et de L Alimentation. 31, 841-858. 

The initial symptoms of aflatoxin toxicity depend on the route of exposure and are described in Table 4.25. The severity of illness is related to the extent of toxin exposure, and acute hepatitis usually predominates in all significant cases. High-dose exposure may result in hepatic necrosis with the subsequent onset of hepatic failure, followed by cerebral oedema, coma and death. 

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). 

Aflatoxins B are fuagal metaboHtes and are produced hyyispergillusflavus. There are several related products all contain a pblorogluciaol segment ia their stmcture and all are extremely toxic and carciaogenic, eg, aflatoxia B (56) (201). 

Aeruginoic acid — see ThiazoIe-4-carboxyIic acid, 2-o-hydroxyphenyI-Aetiocobalamin, 4, 420 Aflatoxin B biosynthesis, 3, 876 Aflatoxin B, metabolism, 1, 245 toxicity, 1, 136 Aflatoxin G, toxicity, 3, 676 ... 

Assessment of whether a chemical has the potential to cause adverse effects in humans arises usually from direct observation of an effect in animals or humans, such as the acute poisoning episodes that have occurred when potatoes contain high levels of glycoalkaloids. Epidemiological studies have also been used to infer a possible relationship between intake of a particular type of food, or constituent of that food, and the potential to cause an adverse effect. Such observations led to the characterisation of the aflatoxins as human carcinogens. However, natural toxic substances that occur in plant foods have often been identified through observations in animals, particularly farm animals. It was observations of adverse effects in farm animals that led to the further characterisation of the phytoestrogens and the mycotoxins. In other instances, the concern arises from the chemical similarity to other known toxins. 

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). 

Moving to toxic compounds, we encounter the infamous aflatoxin Bl, a mycotoxin considered to be a major cause of human liver cancer in some parts of the world. Thus, there are some estimates that, in China, as many as 1 in 10 adults die from liver cancer caused by aflatoxin [205]. Oxidation of... 

An example of the importance of sampling is in the determination of aflatoxins (a class of highly toxic compounds... 

Other preharvest techniques include the development of more resistant crops (e.g., Becker, 1999 Guo et al., 1998), and biological control with atoxigenic A. flavus strains (Cotty, 1990 Dorner et al., 1998). Atoxigenic A. jiavus competed successfully with a toxic isolate when they were grown in mixed culture, obtaining a reduction of the aflatoxin content by 82 to 100%. This is a worthwhile approach for control, however possible side effects caused by a preemptive application of A. jiavus in the environment must be studied to determine potential risks to human and animal health. 

No. The FDA went too far. Aflatoxins can indeed cause liver toxicity in animals and are also carcinogenic. But they produce these adverse effects only at levels far above the FDA set limit. We should ensure some safety margin to protect humans, but 20 ppb is unnecessarily low and the policy that there is no safe level is not supported by scientific studies. Indeed, it s not even certain that aflatoxins represent a cancer risk to humans because animal testing is not known to be a reliable predictor of human risk. Moreover, the carcinogenic potency of aflatoxins varies greatly even among the several animal species in which they have been tested. Human evidence that aflatoxins cause cancer is unsubstantiated. There is no sound scientific basis for the FDA s position. 

A second factor concerns the purity of the diet and water received by the animals. Careful chemical analysis is needed to ensure the absence of significant amounts of highly toxic chemicals, such as aflatoxin, metals such as lead, arsenic, or cadmium, or certain pesticides, that may be present in water and various feed ingredients. 

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