Asia has a long history of aquaculture activity consisting of simple, low-cost, extensive culture methods, mainly for household and local consumption. However, in the past two decades, technical advances in culture methods and systems, and increasing market demand in the light of stagnating wild catches, have resulted in significant increases in production levels and efficiencies, especially in export-oriented sectors of the industry such as shrimp.
According to the Food and Agriculture Organisation of the United Nations, aquaculture’s contribution to global seafood supply has grown from 3.9% of total production by weight in 1970 to almost 30% in 2001 against a background of stagnating capture fishery production (FAO, 2002). It is the fastest growing animal food producing sector, with an average compounded rate of growth of 9.2% per annum since 1970 compared to only 1.4% for capture fisheries and 2.8% for terrestrial farmed meat production (Figure 1).
Aquaculture is of major importance in Asia, which produces around 90% of the total world aquaculture production by quantity (Figure 2). In the past 20 years, Asian aquaculture has developed rapidly, from traditional practices to a significant food production sector and has matured into a better-organized economic sector with a strong private-sector participation. Asia dominates the world in aquaculture production, and its contribution in 1997 to total world production has been estimated at: finfish, 89%; crustaceans (marine) 80%; freshwater crustaceans, 94%; mollusks, 88%; aquatic plants, 98%, and miscellaneous animals and products, 99% (Kongkeo, 2001). The region provides 91% of global aquaculture production by quantity (Figure 2) and over 80% by value (Figure 3) with the top 10 producers in 1998 being Asian countries (FAO, 2000). Much of this production is finfish, particularly species belonging to the freshwater carp family (Cyprinidae), which consists of 23 species that are extensively farmed by small-scale farmers for local consumption. Total carp production in 1998 was estimated at over 12 million metric tonnes. Although by far the most important group of aquaculture products by volume (Figure 3), the carp are generally low value species and are a main staple food item for poorer sectors of society.
Figure 1. Annual average compounded rate of growth of animal production systems.
Figure 2. World aquaculture production by quantity, 1998 (FAO, 2000).
Figure 3. World aquaculture production by value, 1998 (FAO, 2000).
Figure 4. Major aquaculture production by species type (in mmt).
In most Asian countries, the aquaculture sector is dominated by small-scale, family or owner-operated farms, generally of low-value species for local consumption such as carp or tilapia although shrimp is also a major export commodity.
Carp is the major aquaculture commodity produced in the Asia-Pacific region, followed by aquatic plants (mainly seaweeds) and mollusks (Table 1). Shrimp culture, although comparatively low in volume compared to other aquaculture products, has a high value and export potential (ADB/NACA, 1998).
Carp culture has a long history in Asia; and the first known publication on its culture was written in China by Fan Li in 475 BC. They are especially suitable for aquaculture due to their fast growth, ability to withstand sub-standard environmental conditions and efficient conversion of food items low in the food chain, most being herbivores, omnivores or detritivores.
Carp is a staple food item in many countries in Asia and south Asia, and the land area devoted to carp culture is considerable (Figure 5). Its versatility, ease of production, low cost and good nutritional value have made it a popular choice for many international and national development programmes aimed at food and income generation for poverty alleviation and food security. Carp are often cultured as part of an integrated polyculture system with livestock and agriculture, using the agricultural wastes as a source of simple inputs such as manure and waste for fertiliser. Other fish and freshwater crustaceans such as Macrobrachium rosenbergii may also be grown in the same pond. In more intensive culture systems, monoculture may be practised using supplemental feeding and other inputs. Monoculture systems may be found in tanks, raceways, rice fields, and in cages and pens in lakes and rivers.
Table 1. Major carp species grown in Asia.
The number of carp farms in several Asian countries was estimated in 1996 in a survey conducted by the Asian development Bank and the Network of Aquaculture Centers in Asia Pacific (ADB/NACA, 1998). As may be expected, carp farms were numerous in those countries with large rural poor populations such as Bangladesh, Indonesia and India (Figure 6). The size of individual carp farms was, with the sole exception of China, small with most between 0.1 and 4 ha total farm area (Figure 7).
The structure of the Asian shrimp industry is illustrated in Figures 8 through 11.
Figure 5. Number of carp farms in Asia and south Asia by farming system.
Figure 6. Number of carp farms by country.
Figure 7. Average size of carp farms by country.
Figure 8. Number of shrimp farms in Asia and south Asia by farming system (ADB/NACA, 1998).
Asia also produces more than 80% of the world production of farmed tilapia (Oreochromis spp.) (Mair, 2001). This species, initially imported from Africa, has become increasingly important due to the application of genetics, especially the development of hybrid strains, and the selection for growth that has happened on a commercial scale. In 1997, the International Center for Aquatic Resource Management (ICLARM) completed a project, Genetic Improvement of Farmed Tilapia (GIFT), funded by the United Nations and the Asian Development Bank, intended to select the best performing strains for the genetic improvement of farmed tilapia stocks. This has shown great success in developing faster growing strains using combined selection with Asian and African stocks, which has provided an estimated 85% increase in growth compared to the base population (see Eknath and Acosta (1999) for more detailed information on the project).
Figure 9. Number of shrimp farms in Asia and south Asia by country and farming system.
Figure 10. Average farm size of shrimp farms in Asia.
Other genetic manipulations that have had a major impact on commercial tilapia culture in Asia are the development of all-male populations through sex reversal and production of YY ‘supermales’, and the production of genetically male tilapia using YY males in a breeding programme to produce over 95% male populations. These have solved the problems associated with early sexual maturation and unwanted sexual reproduction in commercial culture, which leads to a loss of growth potential and overcrowding problems in production ponds.
Figure 11. Average size of shrimp farms by farming system.
Major issues facing the Asian aquaculture industry
The rapid rate of growth of aquaculture production has led to significant changes in how farmed seafood products are perceived and marketed (Josupeit et al., 2001). In the wake of increasing health-consciousness and food scares associated with meat in the 1990s such as BSE and Escherichia coli O157, seafood has gained in popularity in many markets as a healthier and safer alternative to beef products. This is not to say that seafood is without its own problems, often as a result of improper handling and packaging procedures. In 2000, for example, 200 people fell ill on a cruise ship after eating shrimp contaminated with Salmonella (Anon, 2001). Subsequent investigation was unable to determine if the incident was the result of suspect food handling practices on the ship or through poor handling procedures in the processing of the shrimp in Vietnam, but as a consequence the US Food and Drug Administration increased the level of surveillance of shrimp imported into the US.
In a recent international conference on global aquaculture priorities for the new millennium (NACA/FAO, 2000), product quality, safety and marketing were major themes. This was reflected in some of the strategic recommendations from the meeting:
- Improvements in diets, feeding regimes and harvesting strategies to enhance product quality and nutritional value of aquaculture products;
- Promoting the application and adoption of international food safety standards, protocols and quality systems in line with international requirements such as Codex Alimentarius;
- Adopting international protocols for residue monitoring in aquaculture and fisheries products;
- Appropriate and informative labelling of aquaculture feeds, including information on additives, growth promoters and other ingredients;
- Collection, analysis and dissemination of relevant and scientifically sound information to allow producers and industry operators to make informed decisions and ensure consumer confidence in the food safety of aquaculture products;
- Application of appropriate safety assessments based on risk analysis and the precautionary approach prior to market approval, including products from modern biotechnology;
- Increasing consumer confidence in aquaculture products by ensuring that industry takes responsibility for the production and distribution of safe products, utilising systems that allow traceability of product ingredients, including information on packaging, processing and production conditions.
The drafting committee for this document emphasised that increased consumer awareness and market demand would require producers, suppliers and processors of aquaculture products to improve the quality of their products and enhance product safety and nutritional value. The additional costs could be offset through higher prices, lower insurance rates and increased consumer demand although this is far from clear in many aquaculture markets at this time.
The safety of food traded internationally is governed by a number of international agreements and protocols such as the Codex Alimentarius, a United Nations (WHO/FAO) standard. The Codex applies to all food types and is intended to ensure that products traded internationally conform to a single standard system and do not pose a risk to human health.
The terms of the Codex identify permitted levels of approved additives such as acidity regulators, antioxidants, colouring and preservatives. Hygiene standards are also supplied with respect to contamination with foreign material, microorganisms and chemical substances.
In addition to the Codex, international trade is governed by a number of bilateral and multilateral agreements between trading partners. These agreements may provide more stringent requirements on products to be imported into a particular country or trading bloc, or specify the imposition of varied tariffs on items from or between specific countries.
Intra-national, or in-country, trade is not covered by the Codex although application of the same standards is encouraged. Safety of food products traded domestically is usually covered by national legislation and regulated by one or more government agencies. Legislation on food safety, or the enforcement of such legislation, may be weak in developing countries or those for which quantity of food rather than quality is the primary concern. However, there are clear indications that, as consumers in such countries become better educated and more affluent, the demand for equivalent standards in domestic and exported products increases.
Hazard Analysis of Critical Control Points (HACCP)
HACCP has been used for over 30 years as a means of taking a preventative approach to food safety (Otwell and Flick, 1995) and has since been adopted as the basis for US legislation covering food processing industries (Boyd and Hargreaves, 2000). The HACCP process is shown in Table 2.
Table 2. Basic principles of a HACCP program.
from Filose, 1995
The European Union (EU) has required HACCP implementation for all plants exporting seafood to EU member countries since January 1996. The EU also has a series of HACCP-based regulations governing fish and fishery products (Josupeit et al., 2001). Since December 1997, the USFDA has required all importers in the US and exporters to the US to show evidence and verification that they are using and applying the HACCP system in the processing and handling of seafood products. In a recent survey, the Global Aquaculture Alliance found that, although the implementation of HACCP by US importers and processors required significant investment in time and money to ensure compliance, the response to adoption of the process was generally positive (Flick, 2001).
The HACCP-based regulations were developed primarily to tackle issues associated with human health and food safety in the preparation of food products. The application of the HACCP approach is thus relatively well-defined for handling and processing of seafood products from harvest to consumption. In recent years, however, there has been some emphasis placed on the application of HACCP further back in the production chain. A requirement to adopt HACCP at the production level for farmed shrimp and other aquaculture products would have a major impact on the way that such products are grown and traded in Asia, not least in the requirement for traceability and documentation at each stage of the process. Establishing a HACCP-based system and maintaining detailed records to demonstrate compliance would be complex given the fragmented stucture of the production systems and the predominance of smallscale producers. Successful implementation would require the co-ordinated efforts of many agencies and stakeholders, and may result in major changes in current production and distibution systems especially where post-harvest trade is dominated by a system of small brokers or wholesale auction markets as a result of a need for detailed documentation to allow traceability.
The issue of traceability was addressed in the Conference on Aquaculture in the Third Millennium (Subasinghe et al., 2001). In the section on trade, it was recommended that some system to ensure traceability through the production chain be established. The need for some means of tracing and identifying products through the production chain is an integral part of any effort to promote a system of standards (e.g., Codes of Conduct, organic farming standards, etc.) that requires some verification that the established standards were being followed. Asian farmers are generally small-scale, and in some countries a majority of producers have a low level of education. A requirement for extensive documentation would place an additional burden on these producers.
In 1999, dioxin contamination of Belgian food products via contaminated feed resulted in the EU imposing temporary restrictions on trade in milk and dairy products, beef, pork, poultry, eggs and egg derivatives, and cattle feed. They also initiated scientific investigations to develop an EU policy on dioxins in food and feeds. Dioxins are polychlorinated aromatic compounds formed as a by-product of natural and man-made chemical processes. Of the 210 different dioxin compounds, only around 17 are of concern and some of these are known carcinogens. Dioxins are not soluble in water, are not highly biodegradable and are absorbed in human and animal fatty tissue, thus accumulating in the food chain. Dioxin contamination can vary depending on the origin of the food material. Meat, eggs, milk, farmed fish and other food products may be contaminated above background levels by dioxins due to a high level of local environmental contamination, or to a high dioxin content in fish meal and fish oil. Wild fish from certain polluted areas may be highly contaminated. European fish oil and fish meal fom wild sources, for example, have dioxin levels around 8 times higher than fish meal and oil from Chile or Peru (SCAN, 2000).
As a result of the opinion expressed by the Scientific Committee on Animal Nutrition (SCAN), the EU adopted regulations which came into force in 2002. These set legally binding limits on measured dioxin content with foods exceeding these limits to be excluded from the food chain. The maximum limits established for fish meal, fish oil, fish feed and compound feed are:
- Fish oil: 6 ng TEQ/kg fat
- Fish, other marine animals, their products and by-products with the exception of fish oil: 1.25 ng TEQ/kg product
- Compound feeds, with the exception of feeds for fur animals and feeds for fish (from January 1, 2002 to December 31, 2005): 0.75 ng TEQ/ kg product
- Feeds for fish (From January 1, 2002 to December 31, 2005) 2.25 ng TEQ/kg product (CEC, 2001)
The TEQ is a means of expressing the level of toxicity of dioxins or dioxin-like PCBs. Since each has a different toxicity, the concept of toxic equivalency factors – TEFs – has been introduced. This means that the analytical results of all the compounds are converted into one summary result, the ‘Toxic Equivalent Concentration’ or TEQ. Dioxins have also been subject to an assessment in the US, and the FDA has been sampling feed ingredients with a view to establishing a baseline before making a risk-based decision on any dioxincontaining ingredients.
The impact of such dioxin levels on Asian exporters and producers has not yet been noted. However, the EU has the intention of reviewing their standards in 2006 with a view to significantly reducing the maximum permissible levels. This may lead to further reductions in the availability of raw materials, espcially fish meals and oils, that meet the specifications and give rise to increases in feed costs.
Antibiotic residues in shrimp have been viewed as a problem since the 1980s when semi-intensive and intensive shrimp farming became a major source of exported shrimp products. As early as 1991, the Japanese government threatened to ban shrimp imports from Indonesia and Thailand due to the presence of antibiotic residues, prompting exporters and governments to implement quality inspections for antibiotics before export (Patmasiriwat et al., 1999). Self-imposed restrictions on purchase of antibiotic-tainted shrimp by exporters quickly led to a reduction in antibiotic use as farmers found they were unable to sell their shrimp.
In 2001, detection of antibiotic residues, especially chloramphenicol and nitrofurans in farmed shrimp from China, Vietnam and Thailand, once again brought the issue of antibiotic residues to the fore. Both of these compounds are banned for use in food fish in many countries and the European Union imposed an official policy of zero tolerance for both as long ago as 1994. The development of highly sensitive tests, which reduced detection levels significantly, effectively led to a reduced level of tolerance in the EU and increased the frequency of detection in imported food products from Asia,which were destroyed by the EU authorities. This brought the shrimp trade between these countries and the EU to a halt with exports from Thailand decreasing by over 70%.
One of the main problems was the free availability of many antibiotics to aquaculturists in Asian countries and a lack of effective control over their use. There is also a limited number of veterinarians with experience in aquatic animal diseases, a major constraint that needs to be addressed. If antibiotics and other therapies are to be used effectively, they will need to be applied under the control or supervision of qualified veterinarians. Adequate records of treatment and treatment duration and withdrawal time need to be observed. Building the capacity for such an organised system of aquatic animal health and veterinary procedures will be expensive and is likely to take a considerable amount of time and effort.
Unfortunately, there are few antibiotics which have been officially approved for food fish use and very few residual levels set. Of the antibiotics approved by the US FDA, none are approved for use in shrimp despite being approved for other food animals. The relatively small market for such products, the expense of taking a drug through the approval process and heavy competition have all deterred serious suppliers from addressing the obvious need for safe and effective chemotherapeutants for aquatic animals.
One alternative is to educate farmers to effectively prevent disease and avoid the use of antibiotics. There are indications that this would be possible, as many farmers have stopped the use of antibiotics with few problems - a trend which could be encouraged by a system based on incentives and verification of freedom from antibiotic use or presence of residues in the flesh. This is one of the issues that is addressed by the implementation of codes of conduct which shall be discussed later.
GENETICALLY MODIFIED ORGANISMS (GMO)
One class of contaminants that may be increasingly important in international trade are GMOs. The debate over GM foods is an example of a clear consumer preference despite the contention of many governments and scientists that foods containing GMOs are safe. Consumer groups and large retail chains are advocating the use of non- GM raw materials in foods and animal feeds and many are prepared to pay a premium for food items that do not contain GMOs. As a result, an increasing number of countries are considering legislation to require labelling of food and feed items that contain GM products and a system of testing to determine their presence.
To date there are no GMO aquaculture products traded internationally and little interest in their development due to the high likelihood of market resistance. There is, however, the possibility that GM ingredients used in feeds could result in the detection of GM signatures in farmed seafood products. Soybean meal, in particular, is a major ingredient in many aquatic animal feeds opening up the possibility that GM soybeans may be detected in feeds. Most feed manufacturers are aware of this and are attempting to avoid the use of GM products as raw materials.
AQUATIC ANIMAL HEALTH
Aquatic animals are subject to a number of diseases and, as production increases and production systems intensify, the situation has become more serious. The devastating impact of shrimp diseases over the past 10 years is well documented, and three of these, White Spot Syndrome Virus (WSSV), Taura Syndrome Virus (TSV) and Yellow Head Virus (YHV) are estimated to have cost the world’s shrimp industry billions of dollars in lost production. No less serious on a local level are some of the diseases of freshwater fish that are grown as a staple protein source in many countries. One, Epizootic Ulcerative Syndrome (EUS), caused by a combination of infection with the fungus Aphanomyces invadans and other as yet unidentified factors, has gradually spread throughout many Asian countries, severely impacting the livelihood of small-scale and subsistence farmers throughout the region. As live fish and shrimp are traded around the world, the risk of transmission of these diseases between countries has increased (WSSV transmission for example, is suspected to have been enhanced through the illegal smuggling of shrimp broodstock and postlarvae throughout Asia). More recently, the role of trade in infected shrimp products such as frozen tails and whole shrimp, has led to speculation that this is a possible source of international transmission (Nunan et al., 1998; Lightner et al., 2001).
In 1995, the World Trade Organisation (WTO) implemented the Agreement on the Application of Sanitary and Phyto-sanitary Measures (SPS Agreement). This defines the basis under which countries can impose conditions on imports of animals, plants and their products based on animal and plant health concerns and is intended to promote international tade by requiring all member states to use agreed standards for reducing disease risks associated with imported products. For animals and animal products the Office Internationale des Épizooties (OIE), based in Paris, is recognised as the body setting the appropriate international standards. The members of the OIE consist of the ‘Competent Authority’ (usually the Chief Veterinary Officer) of each OIE member country. Alternative standards to those given by the OIE are permissible, but if the standard adopted is lower than the OIE standard, importing countries using the OIE standards are within their rights to refuse import on the grounds that they have insufficient health guarantees. Standards higher than the OIE standards can also be adopted, but to avoid the imposition of non-tariff trade barriers, the SPS agreement requires justification based on a scientific risk assessment before such standards are imposed. The OIE maintains a list of diseases, including those of aquatic animals, that are considerd a danger to aquatic animal health and for which notification is required. For diseases not listed by the OIE, trading countries may agree on any mutually acceptable standard. The OIE lists all three of the shrimp diseases mentioned above (WSSV, TSV and YHV) as ‘notifiable’ (requiring notification by the national Competent Authority of any new outbreaks to the OIE within 24 hrs) (OIE, 2000). Also, routine monthly reports should be submitted until the disease has been eradicated.
Australia has so far been free of WSSV in shimp. In late 2000, however, WSSV was detected in a research facility in Darwin that had been using shrimp as feed for crabs. Testing by polymerase chain reaction, a highly sensitive test for the presence of viral nucleic acid, revealed traces of WSSV in the frozen shrimp. Further investigation revealed that the shrimp, imported from Indonesia, had been illegally diverted from use for human food to be sold as bait, a practice that had been banned since 1996. In response to this, the Australian government implemented a series of measures intended to control the risk posed by imports of frozen shrimp from countries where WSSV was endemic.
The authorities required an import permit for all uncooked shrimp and shrimp products and that consignments be accompanied by a certificate from the National Authority that whole shrimp had not been ‘emergency-harvested’ due to the suspicion or confirmation of disease, and that they had been processed, inspected and graded in a premises approved by, and under the control of, the Competent Authority. They further required that the shrimp be free of obvious signs of infectious disease and that they be declared as fit for human consumption. Other requirements were that, where the place of harvest was not officially declared free from white spot disease or yellow head disease, the shrimp be greater than 15 g (on the assumption that such small size shrimp had a high likelihood of being emergency-harvested) and that they were packaged and labelled with country of origin and marked ‘For Human Consumption Only’.
Similarly, the outbreak and impact of WSSV in the Americas has continued to cause major disruptions in the international trade in live shrimp broodstock, nauplii and postlarvae as countries close their borders to imports. In most cases, this is clearly in breach of the WTO SPS agreement as the disease is known to be present in many of these countries although official reports may not have been submitted to OIE. (A key clause in the SPS Agreement allows for the open trade in animals and animal products between countries of equal status with respect to a specific disease). These experiences clearly show the potential for animal health issues to disrupt international trade in aquatic animals and their products.
BUYER PURCHASING SPECIFICATIONS
There is increasing consumer awareness and demand for food that is not only safe and nutritious but grown in an environmentally-responsible manner. To this end, many seafood buyers and major retailers have been revising or developing purchasing specifications that take some of these considerations into account. Some draft purchasing specifications cover not only the preparation of seafood and its post-harvest treatment but include the entire production process from hatchery to harvest. These may cover environmental, social and animal welfare issues. For example, one retailer expressed a desire to see an end to the practice of ablation of female shrimp in hatcheries and a switch to domesticated rather than wild sources of broodstock. Another specified standards for feeds that included a requirement for feed suppliers to provide written assurance that their feed did not contain any growth promoting substances, including digestive enhancers, hormones or enzymes, that the feed was free from potential pathogens and that plant protein should be the main component of the feed.
Many of these provisions are currently impractical and have failed to have much impact as their implementation would severely restrict the supply of shrimp to the retail market. However, they do represent a desire on the part of the retailer to be able to source shrimp and other seafood that meet more stringent specifications than those required by government regulations. This has been seized on by some anti-shrimp farming NGO groups, who have targeted their efforts at the retail level, and as a result have had significant influence on their specifications. Such issues have to be tackled by the shrimp industry in a more organised and proactive manner if it is to avoid the imposition of unreasonable or unjustifiable demands and standards. Once again, the fragmented nature of the Asian industry may work against Asian producers. Development of effective national and regional industry associations with the intent to both improve the production process and present a better image to counter the negative perceptions as well as providing an obvious partner for retailers in developing their specifications and providing support for their implementation.
CODES OF CONDUCT
In most Asian countries, laws and regulations pertaining to aquaculture are rudimentary and enforcement is often inadequate to protect environmental quality (Boyd and Hargreaves, 2001). Codes of conduct are voluntary systems of principles and guidelines on how management and other operational activities should be conducted so as to avoid undesirable consequences. As such, they can provide a valuable complement or alternative to regulation.
The FAO Code of Conduct for Responsible Fisheries (FAO, 1997) includes some provisions on aquaculture asserting that “States should consider aquaculture...as a means to promote diversification of income and diet. In doing so, States should ensure that resources are used responsibly and adverse impacts on the environment and on local communities are minimised.”
The FAO Code provides a series of guidelines but does not contain any detailed specifications on management practices. Consequently, several code of conduct initiatives have been developed pertaining to shrimp farming which include more detailed technical information on recommended ‘Best Management Practices’ (BMPs). Such codes of conduct have been drawn up by, among others, the Global Aquaculture Alliance, the Australian Prawn Farmers Association, the Marine Shrimp Culture Industry of Thailand and the Department of Fisheries of Malaysia (Anon., 1998; Boyd, 1999; BTG-Golder Company, 1999; Donovan et al., 1998). All of these codes have features in common, generally dealing with environmental impact of shrimp farming although some also cover social responsibility and employee welfare issues. Implementation of such codes in Asia will be complicated due to the predominance of small-scale farmers in the region as they have limited resources to aid compliance and tend to be less well-educated and financed than their counterparts in the west. Government and international assistance and funding for implementation of Codes of Conduct will be essential in most Asian countries, especially in less well-financed sectors.
The Asian aquaculture industry, as with the the aquaculture industry worldwide, has shown rapid growth in the past 20 years to become a major supplier of food both for domestic consumption and for international trade. In recent years, however, new pressures have come to bear on the aquaculture industry with concerns over environmental, food safety, aquatic aniomal health and other issues. The dominance of small-scale farmers, long seen as an advantage in Asian aquaculture, now represents a major challenge in addressing the current concerns over the future of aquaculture. How the aquaculture industry in Asia faces up to these challenges in the next 10 years will be a major factor in determining the success or failure of the commercial aquaculture industry in Asia.
Author: DAN F. FEGAN
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Shrimp Biotechnology Business Unit, National Center for Genetic Engineering and Biotechnology, Bangkok, Thailand