Food and Fertilizer Technology Center - publications

Jun. 01, 2003

The Safety of GM Foods

Genetic engineering, or recombinant DNA technology, began in the 1970s. It involves the genetic modification of living organisms by combining the traits or genes of different species. Since 1996, a growing area of genetically modified (GM) crops have been planted, reaching 58.7 million hectares in 2002. Most of this planted area involves only a few crops (soybean, corn, cotton and canola) and a few countries (United States, Argentina, Canada and China, the last accounting for only 4% of the total). However, each year GM crops are becoming more common. It is now estimated that 75% of the soybeans grown in the United States are the GM crop Roundup Ready.

Many Asian countries import large quantities of soybeans and corn, both for human consumption and as livestock feed. They are thus consuming large amounts of GM crops, even though they themselves may not be growing any.

An important aspect is the impact of GM crops on Asian smallholders, whether and how they should be assisted to gain access to the products of this new technology. Another is how to combine GM and traditional crops without cross-contamination on the small intensive farms of Asia.

Consumption of GM Crops


Most Asian countries have decided to adopt a mandatory labeling system for foods containing GM crops. Their governments feel that food safety is related to the consumers' right to know what is in the products they buy. However, no government insists that food must be completely free of any GM ingredients in order to be labeled a non-GM food. There is a tolerance level, since in practice it may be difficult to ensure that foods are completely free of any GM ingredients. The threshold level in Korea is 3%. Over this level, foods must be labeled "Genetically Modified" or "Containing Genetically Modified Ingredients". In Indonesia and Taiwan, the threshold level is slightly higher, at 5%.

Regulations about labeling of GM foods do not mean much unless there is some way of distinguishing such foods in tests. Otherwise there is no way to tell if foods are being labeled correctly. An important topic of discussion was how to identify GM products, mainly based on laboratory tests. PCR testing is generally used to distinguish the DNA of GM crops. It is difficult for less industrialized countries to fund this type of advanced genetic testing.

Processed Foods

Identifying GM crops in processed foods is especially difficult. Tofu and other forms of processed soybean are popular foods in Asian countries. However, most processing techniques involve heating the soybeans, which destroys much of the DNA, as does long-term fermentation (i.e. more than 100 days, as in the case of "miso"). Scientists in the region are developing systems based on amplified DNA, which can distinguish GM crops used as ingredients in processed foods, even after lengthy processing.

Discussion on Labeling

Whereas most food labeling issues are safety issues, in the case of GM crops, labeling has nothing to do with safety. The basic concept in the labeling of GM foods is to guarantee to consumers their right to choose.

Production of GM Crops

Apart from China, Asian countries are not yet producing GM crops for commercial sale. Some are growing test GM crops, either in greenhouses or in isolated fields carefully quarantined from traditional crops of the same species. Of particular concern is the possibility of contaminating traditional non-GM crops, so that eventually all of the region's crops may include some genetic material from GM crops, however small.

Pollen Drift

There has been a published report from the United States that larvae of monarch butterflies had a high death rate when they were fed pollen from GM corn made resistant to corn borer by introducing Bt (
Bacillus thuringiensis
) genes. Experiments were carried out in Japan to test corn pollen dispersal. Neither corn variety used in the experiment was a GM crop, but one variety had yellow grains and the other one had white grains.

Prevailing winds blew from the yellow variety, which therefore acted as the donor, to the white variety, which was the receptor. Movement of pollen, and therefore genetic drift, was recorded by observing the number of yellow grains in harvested corn cobs of the white variety.

It was noted that the fallout of pollen from pollen drift fell sharply with increasing distance from the cornfield. Over the research period, 64% of the pollen was deposited within 10 meters of the crop. However, pollen drift did not fall to zero even at a considerable distance from the corn field. This means that quarantine by distance may not halt all genetic dispersal from GM corn crops, even though the level may be very low. Genetic drift is likely to be higher in the case of rice, since rice pollen is lighter than corn pollen. It is more easily windborne for some distance.

Pollen Drift and Genetic Contamination

There is the question of compensation for genetic contamination of crops. Two adjacent farms might be growing soybeans, one growing GM and the other growing non-GM varieties. Eventually, the non-GM soybeans might become contaminated, so they could no longer be sold as non-GM soybeans. This might mean a considerable loss for the farmer. In Korea, for example, the price of domestic soybeans, which are all non-GM, is four times higher than imported ones. The problem of accidental contamination in the field was seen as a particular danger for self-pollinating crops such as rice.

One possible solution is to place the GM gene in the chloroplast. Since pollen does not carry chloroplasts, there would be no danger of contamination from pollen.

Future Outlook

At present, GM crops are mainly developed in order to be herbicide-tolerant or pest-resistant. The people who mainly benefit from such crops are the farmers rather than the consumers. This could perhaps be seen as the first step in the development of GM crops and products.

The second step in GM crops may be value-enhanced varieties. For example, soybeans may have enhanced nutritional properties, such as modified fatty acids or increased levels of Vitamin E. This might be of benefit to human health, or might increase feed efficiency in livestock production.

The third step in the future development of GM crops may be to use plants as factories, producing, for example, high-value pharma-ceuticals at a relatively low cost. Some typical products might be protein-based drugs and biodegradable polymers.

Regulations to Reduce Risk

Nearly countries in Asia have regulations and structures in place to monitor the use of GM crops. There is general agreement that the same regulatory protocols should be applied to imported GM crops as to the locally produced ones.

It has been suggested that, not just at a regional level but at a global level, we need a common ground of regulatory measures, to govern the movement of GM products from one country to another. The Cartagena Protocol is an important first step in this direction.


Discussion about GM crops has tended to polarize. On the one hand, those working to develop GM crops tend to emphasize their benefits, such as an increase in yields and pest resistance, and a reduction in pesticide applications and erosion (because some GM crops can be grown using no-tillage).

Opponents usually emphasize the risks to human health: the fears that eating GM crops may increase the incidence of cancer, birth defects and allergy problems. Other concerns are for the environment, that there may be genetic contamination of traditional crop species, and of related wild species, or that crops intended to kill pests may accidentally damage wildlife. There is also the danger that pesticide resistant crops may induce the same trait in related weed species, thus giving rise to "superweeds".

Scientists working with GM crops emphasize the lack of evidence that GM crops cause any damage to human health or the environment. They pointe out that gene transfer by genetic engineering is a more precise, and therefore more predictable, process than conventional plant breeding.

In response, many people say that it does not do any harm to be cautious about GM foods. The widespread consumer avoidance of GM foods does not represent a rejection of the technology, but an uncertainty based on lack of unbiased information from an independent party.

With regard to GM foods, while there is no data that they are harmful, there has been no systematic study of the effect of GM foods on human health. We know that in the past, human behavior has damaged nature in a way that cannot now be redressed. To avoid this happening again with GM foods, it might be better to get more evidence that they are safe and sustainable. Otherwise future generations will pay the price, as well as the present one.

In summary, while some countries such as the United States have advanced technology, most countries in the region are in a similar situation, in that most of their farmers are smallholders. Their problem is how to adapt to this new technology, not just in terms of labeling imported GM products, but in terms of the effect GM crops will have on their own small-scale farmers.

Furthermore, many Asian consumers are concerned that imported GM foods are already widespread in the region's food supply. The consumption of GM foods is widespread in the region, whether direct or indirect. Two important questions remain to be answered. The first is: How can smallholders in developing countries gain access at an affordable cost to the GM products being developed? The second is how consumers can safely and without any doubts eat GM foods.

International FFTC Workshop on Impact and Biosafety of Genetically Modified Organisms

Held at National Taiwan University, Taipei on September 9-14

No. of countries participating: 8 (Indonesia, Japan, Korea, Malaysia, Philippines, Taiwan, Thailand, Vietnam)

No. of Participants: 14 plus more than

100 observers

No. of papers presented: 12

No. of participants: 14 plus 100 observers

Co-sponsor: National Taiwan University

Index of Images

Figure 1 Soybeans for Sale in a Korean Market. the GM Soybeans (the White Ones at Center Front) Are Identified with a Label.

Figure 1 Soybeans for Sale in a Korean Market. the GM Soybeans (the White Ones at Center Front) Are Identified with a Label.

Figure 2 Voluntary Label on

Figure 2 Voluntary Label on "Non-GM" Soybeans

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