SOLUTIONS TO THE IDENTIFIED PROBLEMS
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Aflatoxin control programs offer opportunities for economic gains as well as health improvement. It is now recognised in many developing countries that reducing aflatoxin residue levels in food or feed can confer international trade advantages. In addition, there may also be long-term health benefits for the local population (Dichter, 1987). Several researchers have suggested possible solutions. Some solutions are given as follows:
1. Specify an Appropriate Sampling Scheme for Different Types of Crops
The International Association of Oilseed Crushers Standard Procedure (IAOCSP) has come up with a sampling procedure for oil seeds but this procedure is not rigorous enough to be used in aflatoxin research and trade (Jones, 1972). Therefore this method should be re-evaluated. Intensive testing would be done on the improved procedure before adopting it as sampling standard.
A design of sampling plans that would provide representative samples of lots of contaminated commodities could be another way to overcome the variability of aflatoxin. Moreover, research would be necessary on the distribution characteristics of aflatoxin as a prerequisite on the design of statistically valid sampling plans. Such plans are essential in reducing sampling error as a possible major source of variance in analytical results obtained by the buyer and seller of a given lot of produce.
Sampling should be done by trained personnel. This is one of the causes of variations. As much as possible, a lot for sampling, i.e., train, ship, etc. should be made by the same person or group of persons to eliminate personal bias.
The methods to increase the precision of aflatoxin test are to increase the sample and subsample sizes and increase the number of analysis. The US Food and Drug Administration (FDA) has advocated a minimum sample size of 6.8 kg. A properly drawn 21.8 kg. (48 lb.) sample is a representative of 45.5 tons. Currently, the FDA recommends 66 kg. (144 lb.) for the control of aflatoxin in peanuts. Increasing the sample size has the advantage of simultaneously reducing the number of good slot rejected and the number of bad slot accepted (Hungsuwong, 1989). Pithaya-Acharlyakul (1989) cited that four 2-kg. subsamples should be set aside for aflatoxin analysis. Each subsample should be crushed, sieved, mixed and reduced by increment reduction method to obtain 50 gm. for analysis. The procedure for the specification of 50 ppb aflatoxin level is given as follows:
1st analysis = over 75 ppb
- rejected and not qualified for 2nd analysis
= up to 75 ppb - allowed for 2nd analysis 2nd analysis = less than 25 ppb - the lot is accepted
= over 25 but less than 75 ppb - allowed for 3rd analysis 3rd analysis = average with former 2 analysis is 50 ppb or below - can be accepted
= average with former 2 analysis is over 50 ppb - rejected - rejected
2 Improvement of the Traditional and VillageLevel Storage Structures
Storage facilities are of particular importance since bulk handling and storage of food grains have become a necessity in many parts of the world due to the seasonality of the crop and because consumption is continuous. Several types of storage structures which have been used by the farmers for a long time. Some of them are good in terms of their structure and appearance but still inadequate for fungal control. Research should be undertaken to find methods to improve the systems . Bhat (1987) stated that the national agencies in different developing countries should emphasise on project which are not capital intensive like improving the traditional existing storage structures. Also, a design of appropriate storage structures suitable for different commodities in different regions should be encouraged. A good storage structure prevents insect and rodent infestations, protects from moisture and humidity changes and mould infection. An improved storage is perhaps, better than introducing a new storage structure due to the financial capability of the farmers. A good example of this is the improvement of the traditional crib store of maize in African regions. FAO (1980) concluded that the use of improved cribs which fully exploit the drying capabilities of natural air appear to offer the most practical and economical method drying and storing maize cobs.
Small-scale middlemen in the village should also be encouraged to make a good warehouse which would give ample protection to the produce while in temporary storage.
3. Adoption of New Cultural Practices
Cultural practices have been proven to influence aflatoxin contamination of the crops. Appropriate agronomic practices such as correct water application, application of fertilisers, control of insect pest and field hygiene must be practiced by the farmers (Jones, 1986, Blanc, 1987, Machmud and Burford, 1989 and Nibe, 1989).
4. Breeding of Aflatoxin Resistant Varieties
Unfavorable climatic conditions could not be controlled by farmers thus, planting of aflatoxin resistant varieties may alleviate the situation. Darrah (1986) reported that no germplasm which would reduce aflatoxin B1 infection in maize kernels have been identified. Therefore, intensive breeding programs for cereal and groundnut should be mace and implemented. These would take time since these will require thorough screening and location testing but once successful, these would serve as breakthrough in aflatoxin reduction. Suttajit (1989), pointed out that the development of 'superplant' against pathogenity utilizing genetic resistance to mycotoxin contamination should be encouraged.
5. Inhibition of fungal Growth
FAO (1979) and Suttajit (1989) pointed out that the inhibition of fungal growth can be achieved by physical, chemical and biological means. These include immediate reduction of moisture content on freshly harvested produce, minimize harvesting damage and provide a good storage, use of synthetic fungicides and the use natural products from plants.
Since sundrying may not be always feasible during the harvesting period, mechanical dryers are recommended. However, large capital investment is necessary. Mechanical dryers could be set-up in a strategic and accessible place in certain villages so that farmers in that village could dry their produce easily if sundrying is not feasible. This necessitates firstly, careful planning such as staggered planting so that crops from all farmers could not be harvested and stored at the same time and secondly, observance of recommended cultural practices. Another way is to provide a mobile dryer (Mekvanich, (1989). This would be appropiate in areas where rural transportation infrastructure crisscross the hinterland villages. The Department of Agriculture in Thailand has designed, developed and tested a mobile dryer.
Ilangantileke (1987) and Cardona (1988) reported that chemical treatment for prevention of fungal growth on maize has a promise. The results of their studies revealed that Nilspor Plus, a propionic acid based fungicide could suppressed aflatoxin development on freshly harvested maize. Tanboon-ek (1989) reported that ammonium bis propionate and propionic acid would give temporary control and prevention on fungal growth in high moisture maize but would not destroy the aflatoxin present before the treatment.
Suttajit (1989) cited that the natural products from plants such as allicin from garlic and onion extracts, clove oil, cinnamon extracts, black and white pepper could be used for fungal control. Bhat (1987) stated that dried leaves of certain plants are mixed with foodgrains to be stored to prevent insect and mould infection.
6. Promote Aflatoxin Hazard Campaign
The aflatoxin problem is not very well-known to all farmers and perhaps, to legislators, businessmen and other grain handlers in the Asian countries. It is only popular to the researchers and medical personnel. Once people are made to understand the danger of aflatoxin, they would be careful in selecting food and feedstuffs. The incidence of aflatoxincosis in humans has commonly observed among the rural people. Therefore, the national agencies of every country should initiate a program to educate the peasant or small farmers. Government and private agencies should join hand to disseminate the information particularly to the most remote villages. Radios and televisions must have a regular program about aflatoxin hazard. Pamphlets and posters would also be used. Moreover, there must be regular features on the subject in widely circulated daily newspapers of Asian countries.
7. Sponsor Seminars and Symposia
Seminars and symposia are good avenues to exchange findings and to get acquainted with the research work from other research agencies. This activity should be promoted locally and internationally. In Asian countries, the ASEAN Grain Postharvest Programmes (AGPP) organises an annual seminar on grain postharvest technology to update scientists in the ASEAN region on advances in research and development in grain postharvest technology. Such a gathering gives researchers a chance to evaluate the past and present studies and consequently plan for future research priorities.
8. Establishment of Mycotoxin Surveillance Programs
The government planners would be encouraged to establish aflatoxin surveillance programs. This would need resources but FAO (1977) stated that this program would be feasible and desirable with the start of modest resources. Experience could be earned as time goes by and all other resources could be secured especially if the performance rating is high. Furthermore, FAO (1977) cited that entry of the programme would start with the establishment of food control laboratories, training of inspectors and analysts in the principles and practices of sampling, sample preparation and mycotoxin analysis.
9. Consultation with Local Veterinary and Medical Authorities
Aflatoxicosis both in humans and animals has been reported. Consultation with persons dealing with aflatoxicosis problems would provide insights for the researchers to initiate survey and regulatory control activities. International bodies such as WHO and FAO might gather information on diseases on humans and animals that are of unkonwn origin and identify those for which mycotoxin hypothesis may be wanted Such work including investigations are needed before one can begin to estimate the extent to which the mycotoxins contribute to disease (FAO, 1977).
10. Incentives for Removal of Mould Contamination
One of the most effective methods for reducing mycotoxins in the food supply is to encourage diversion of mouldy grain and oilseeds to non-food uses or to processing industries that recover one or more mycotoxin free products. When alternative markets do not exist for the mouldy product or if the price is much less than for non-mouldy products, there is a large economic incentive to blend the mouldy with non-mouldy products, there is a large economic incentive to blend the mouldy with non-mouldy products so it can be marketed for food uses (FAO, 1977).
11. Work on Feasible Detoxification Techniques
Since aflatoxin is a naturally occurring contaminant of several staple food products, it cannot be completely eliminated without compromising the food supply and creating significant economic losses (Dichter, 1987). The removal of aflatoxin from contaminated produce entails additional cost therefore, a cheap method of detoxification must be work out. Various studies have been done on aflatoxin removal of inactivation based on physical, chemical and biological processes (Brekke et al. 1977, Huff and Hagler, 1982 and Lillehoj, 1987). Ammonia has been found to be the most efficient detoxification method (Huff, 1980) but further work must be undertaken on this aspect. Tanboon-ek (1989) commented that maize with high aflatoxin content can be detoxified efficiently with ammonia and the resulting grain is safe and can be fed for cattle and swine but not suitable for human consumption. Therefore, further studies should be carried out so that an appropriate detoxification technique could be attained.
12. Collaborative Research
Since aflatoxin research needs considerable resources, a cooperative research activity may be a better approach. These have been done in the Philippines, Thailand and India and the outcomes seem to be very encouraging (Bilgrami and Sinha, 1986, Buangsuwon, 1986 and Garcia and Ilag, 1986). It would be appropriate then to strengthen cooperative research within one country and between other countries.
13. Training Programmes
The technical expertise of those who work on aflatoxin, especially those who would perform sampling and laboratory analysis is a crucial factor for effective aflatoxin control programmes. Training is a very important component and it would be logical to sponsor training programmes periodically. A recent training activity was done by Thailand and was supported by FAO, AGPP and the Royal Thai Government. This training program had participants from different countries in Asia.
14. Inclusion of Mycotoxins in the University Curriculum
Campos (1987) recommended for a possible inclusion of mycotoxin in the curriculum is the department of agronomy, veterinary sciences, food technology, medicine. chemistry and pharmacy. Bhat (1987) stated that the information on mycotoxins has to be incorporated in the syllabus at various level for certificate, diploma and the courses offered for agricultural extension workers. This would have a great future benefits for all countries.
15. Promulgation of Policies on Aflatoxin.
Policymakers in the national government should be aware of the health benefits as a result of the preventive health strategy that successfully reduced human exposure to mycotoxins. Dichter (1987) commented that decreased exposure to aflatoxin would result in fewer deaths from liver cancer, a chronic disease, which takes perhaps 20 or more, years to develop.
Aflatoxin legislation has been enforced in other countries like U.K., U.S.A., Canada and the E.E.C. member countries. An aflatoxin legislation should also be instituted in the developing, countries where incidence of Aflatoxicosis is high. However, Campos (1987) cautioned that in introducing an aflatoxin legislation, a certain country should not copy the legislation of other countries and adopt it in toto as its own national standard.
The aflatoxin tolerance or limit varies widely from one country to another. This should be standardized and the tolerance level should be reduced. Van Egmond (1987) cited that harmonization of mycotoxin regulation is highly desirable. Effort should be made to standardize and harmonize the methods of determining the aflatoxin level in bulk commodities to eliminate or minimize injustices.
Some problems associated with aflatoxin research have identified. Effects of aflatoxin on humans and animals were also reviewed. Consequently, recommendations from different agencies working on aflatoxins are thoroughly reviewed.
If the recommendations from all these agencies would be implemented, perhaps, aflatoxin problems in Asian countries would be minimized if not solved.
Appreciation is hereby extended to Mr. Robert L. Sample and Mr. Johannes Dommershuijzen of the FAO Regional Office in Bangkok, Ms. Donna SchenckHamlin of Kansas State University, U.S.A., Ms. Boontharee Phoonchai of LRDC, AIT and the Div. of Plant Pathology and Microbiology, Dept of Agriculture, Bangkok for their help in collecting the aflatoxin literature.
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