Aflatoxin chemical degradation

Procedures aimed at reducing or detoxifying aflatoxins and/or their effects have been reviewed by Phillips et al. (35), and include technological procedures for food and feeds and chemical degradation, as well as biocontrol and microbial inactivation, dietary modification and chemoprotection, and reduction in toxin bioavailability via selective chemisorption with clay. 

The various techniques of dispoal of wastes contaminated with chemical carcinogens are then discussed and some validated chemical degradation methods presented for the treatment of wastes and spillage containing aflatoxins, N-nitrosamines, N-nitros-amides, polycyclic aromatic hydrocarbons, hydrazines, aromatic amines, haloethers and some antineo-plastic agents. 

Chemical methods The greatest attention has been paid to the possibility of chemical degradation of aflatoxins. The most important method is decontamination with ammonia. Other agents tested were sodium hypochlorite and hydrogen peroxide. Practical apphcation of the last two agents is problematic due to unwanted oxidation of a number of treated material components. Aflatoxins Bj and Gj and patuhn are partially degraded by sulfur dioxide. 

Chemical detoxification processes or decontamination will include degradation, destmction and/or inactivation of the mycotoxin. In any such process the reduction of the mycotoxin to safe levels should not result in toxic degradation products or reduce the palatability or nutritional properties of the commodities. Aflatoxin has been the subject of most studies and only a relatively small number of these offers any hope of success. There is as yet no FDA or EC fully approved method for aflatoxin detoxification in human foods. Current methods in advanced stages of approval use ammonia in the gaseous form or as an ammonium hydroxide solution at various temperatures, pressure, moisture contents and reaction time to degrade aflatoxins in various animal feedstuffs. There have been extensive studies using two processes, viz ... 

A wide range of chemicals have been tested for the ability to degrade and inactivate aflatoxins. However, although a number of these chemicals can react to destroy aflatoxins effectively, most are impractical, too expensive or potentially unsafe because of the formation of toxic residues, or the perturbation of the nutrient content of the food. Two chemical approaches that have received considerable attenhon are ammoniation and reaction with sodium bisulphite. 

Studies have shown that treatment of aflatoxin-contaminated corn with ammonia is an effective detoxification approach. Ammonia appears to produces hydrolysis of the lactone ring and chemical conversion of the parent compound to numerous products that exhibit greatly reduced toxicity. Similarly sodium bisulphite reacts with aflatoxins to form water soluble degradation products. 

Using this approach, methods were established for the degradation of selected compounds in the following seven classes of chemical carcinogens aflatoxins, nitrosamines, nitrosamides, polycyclic aromatic hydrocarbons, hydrazines, haloethers and aromatic amines. A first study was also set up to investigate methods of degradation of some antineoplastic agents,... 

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