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by Thirapong Tangthirasunan
Thailand is an agricultural country. Agriculture has played a vital role in the Thai economy contributing around 25% of the gross domestic product (GDP) and about 55% of export by value.
Thailand's economy still depends on the successful export of its major agricultural commodities. Problems in export of agricultural products are many and varied.
Firstly, it subjects to the uncertainty of the world commodities market including the importing policy of the buying country.
Secondly, for some specific crops such as maize, it is more difficult as world production continue to rise faster than demand. The maize buyers now emphasize quality particularly the level of aflatoxin.
Formerly, Thai maize was preferred for its bright yellow colour and high protein content. Today, however, these qualities are overlooked as a result of high level of aflatoxin. This has seriously affected the demand for Thai maize.
In recent years the quality of Thai maize has suffered through high level of aflatoxin, a mycotoxin produced by a fungus thriving in moist condition and poisonous in concentration. The effect on Thai economy has been substantial through lost export market and discounted prices. The Thai farmers, many of whom are often subject to unfair practices of the middlemen and the private local traders, have seen the price depressed accordingly.
Thailand is the world's third largest exporter of maize, and maize contributes significantly to the country's foreign exchange earnings. Thai maize is exported freely, with major customers in Singapore, Malaysia, Hongkong, Taiwan, Korea, Middle East and more recently in Africa. Over 60% is exported in the period from September to January, largely influenced by the season of harvest and seasonal price advantage.
It is generally realized throughout that Thai maize suffers from a US$ 10-20 per tonne quality discount on the world market. These losses will continue to rise unless real efforts are made to control aflatoxin and improve quality.
There have been significant changes in the export markets for Thai maize. In 1981/82 Japan purchased 20,400 tonnes and Taiwan purchased 235,000 tonnes. In 1983/84 these purchases were 9,500 and 1,000 tonnes respectively. Such decline purchasing always referred to aflatoxin. In recent years the price of Thai maize has also fallen in relation to other sources of supply reflecting a decline in quality associated with the incidence of aflatoxin.
Levels of aflatoxin acceptable to Japan are less than 20 ppb. Other countries required levels of less than 50 or 100 ppb. Thai maize frequently exceeds these levels, in the rainy season. Because of the high incidence of aflatoxin, Thai maize regularly trades at $15-20 per tonne below comparable maize from other sources. The annual cost to Thailand of the aflatoxin problem is not less than $50 million per annum according to the report on the findings of the ThaiBritish aflatoxin Project, 1984.
Aflatoxin is measured in terms of parts per billion (ppb.) Acceptable levels in importing countries are generally in the range 30-100 ppb. Levels of aflatoxin found in the stores of regional merchants in Thailand generally exceeded these levels.
In Thailand there is little contamination before harvest and contamination occurs mainly in the period immediately after harvesting and during primary processing.
It appears that most farmers dispose of their maize as soon as possible after harvest. Usually, harvesting may occur over a 10-14 day period, during which time the maize is bulked up often in moist, if not in wet conditions. In terms of aflatoxin contamination, this bulking up period is not considered as "storage" although in critical period. This storage period may be longer if the roads are impassable due to heavy rain, or if there is delay with transport or in the arrival of the mechanical sheller.
Maize is typically a low input-low output system. About half of the maize crop is stored on farm for at least 60 days-frequently in a moist condition. Many farmers store temporarily while bulking up enough for sale. Storage bulking up delays in drying and queuing problems in the merchant sector, together with the humid ambient conditions, create ideal conditions for aflatoxin contamination.
It appears that, in general, those involved in the marketing and utilisation of maize in Thailand are generally aware of the problem of aflatoxin. What they lack is information about the problem, practical proposal for its solution and financial incentives to implement the appropriate measure.
Following the above, the Thai-British Project for the control of aflatoxin in maize was established in 1984 to investigate the incidence of aflatoxin in Thai maize and to determine whether its level can be controlled by effective drying. This project was undertaken by the staff of the Rural Investment Overseas Company Limited in conjunction with Silsoe College and the Tropical Development and Research Institute now the Overseas
Development and Natural Resource Institute, or ODNRD from the U.K. Also the Thai team comprised of officers and technicians from the Department of Agriculture, Office of Agricultural Economics, Bank for Agriculture and Agricultural Co-operatives and some private sector in the upcountry rural areas.
After Phase III is completed it indicated that the combined effort of the Thai Government, the maize industry and the participants of this project have been successful in demonstrating an effective method of aflatoxin control. Thailand is now in a better position to reduce the aflatoxin problem in maize to acceptable levels following the application of this research on a much wider national scale (see following sections for more comprehesive review of conclusions and recommendations from the project)