|Food Chain No. 21 - July 1997 (ITDG, 1997, 20 p.)|
A MANUAL FOR THE DETECTION AND CONTROL OF MYCOTOXINS
Any readers requiring further information should contact the author Professor Eguiazu, INCABIE, Tecnogenia Ambiental Alimentos, UNR, Conicet, Beruttie 1866, CC721-2000 Rosario, Santa Fe, Argentina
Linking with the leader of this issue, we have received a communication and booklet (in Spanish) from Professor C M Eguiazu, Professor of Environmental Technology at the Instituto de la Calidad Biologica y Ecotoxicologia (INCABIE) in Argentina, in which he raises concerns about the loss of natural immunity found in native grains with the advent of 'improved' imported grains. This manual was translated by B. Axtell from the review by Ritva Repo-Carrasco, La Molina University, lima, Peru.
An interesting research manual on mycotoxins with a particular focus on aflatoxins has been published by the National Rosario University, Argentina. The work provides important support in trying to resolve problems caused by mycotoxins in grains and other farm produce. Mycotoxins are toxic substances produced during the metabolism of certain types of moulds. Aflatoxin, produced by Aspergillus flavus is one of the most dangerous, producing a carcinogenic toxin. For this reason it is very important to be able to detect and control this substance in foods. A Flavus has been found in maize, peanuts and in sunflower, and if the conditions are favourable it can grow and produce toxins in these products. It is important to remember that the toxin can be transmitted to other products such as milk, eggs and meat, if contaminated food is fed to animals.
The booklet by Professor Eguiazu falls into four parts. The first is a revision of regulations on the control of mycotoxins in foods. The second and third describe methods for the detection and quantification of aflatoxins under field conditions. The final part presents a hypothesis on the weakening of the storage properties of products such as maize and sunflower.
The writer suggests that mycotoxin regulations should control at the very least, aflatoxin, but he mentions that there are other mycotoxins such as patulin. Each Latin American region should define the most common mycotoxins but aflatoxin and esterigmatocistin must always be included in control lists, both having demonstrated carcinogenic properties. Controls should take into account specifications of the USFDA and the general recommendation is to maintain the lowest possible human exposure level.
According to the author, regulations on aflatoxin determination must take into account: a simple, cheap and reliable detection method; an obligation to test foods for human consumption for aflatoxin; punitive measures if merchandise exceeds limits and against those who use contaminated material for animal feed; basic materials requiring control should be maize, peanuts, cotton meal and sunflower. The book presents a rapid simple and cheap method for measuring aflatoxin requiring simple equipment and reagents that are easy to obtain.
Different chromatographic methods, micro-columns and thin layer, were tested to separate aflatoxins from interfering substances. While thin layer prove d the most efficient it had several disadvantages, particularly cost and space requirements. A method was thus developed termed an autoclavable chamber/plate chromatography that was economic in use of materials and easy to activate. This method, which represents the extreme simplification of thin film chromatography that can be used at low cost under field conditions, has been patented.
Finally the author presents an hypothesis related to the weakening of the storage characteristics of cultivated plant species. He considers that mans selection of species based on characteristics such as yield and grain size has modified their resistance to mould attack. In addition, storage practices actually modify the surface microclimate of grains so favouring the development and growth of soil fungi. He considers that mans modification of the germoplasm of species and the use of new storage methods present the possibility of significant appearance of mycotoxins in food.
This is an important book related to the implementation of mycotoxin control. The methods, described in great detail, are relatively simple to implement in any laboratory. To date there has been no work specifically related to mycotoxins in Latin America where the risks of contamination are high and environmental conditions are favourable for mould growth.