11 July 2005

More on GM foods

Have you ever wondered which foods are genetically modified? And how much you are eating of them? DietDoc takes a closer look.

Last week in Part I of this series of articles on genetically modified (GM) Foods, we looked at aspects such as public reaction, food safety and allergenicity.

But many people wonder which foods are genetically modified, both in South Africa and other parts of the world.

Global production
It is estimated that the global area of GM crops in 2003, was 67.7 million hectares grown in 18 countries throughout the world by more than 7 million farmers. Many of these farmers were from developing countries with small, resource-poor farms.

The increase in GM crops has grown exponentially. From 1996 to 2003, the global area producing GM crops increased 40-fold from 1.7 million hectares to 67.7 million hectares.

In 2003, there were six main countries growing 99% of global GM crops. Of these countries, the USA led the field with 42.8 million hectares, followed by Argentina (13.9 million), Canada (4.4 million), Brazil (3 million), China (2.8 million), and South Africa (0.4 million hectares).

The greatest increase in GM crop production with a 33% growth rate was experienced in China and South Africa.

30 000 field trials have been conducted with more than 50 GM crops in 45 countries. If it is kept in mind that more than 300 million hectares of GM crops have been grown commercially over the past 10 years with no documented adverse effects to humans or animals, then the general safety of GM crops has been demonstrated repeatedly.

In 2004, more than 85% of the soya beans planted in the US were genetically modified, while 45% of the American maize crop and 76% of the cotton crop were GM.

GM crops
The so-called 'first generation' of GM crops include the following:

  • Maize
  • Oilseed Rape
  • Papaya
  • Potato
  • Soya
  • Squash
  • Sugar Beet
  • Tomato
  • Chicory

It is interesting to note that the first GM crop grown in the US was a long shelf-life tomato, which was produced in 1994.

GM crops in South Africa
In the period 1990 to 1999, the South African government did an interim biosafety assessment and participated in a decision-making process involving a scientific advisory committee SAGENE (SA Committee for Genetic Engineering), which culminated in the Genetically Modified Organisms (GMO) Act, No 15 of 1997.

After controlled field trials with GMOs commenced in 1990, the first conditional commercial release permit was issued by the National Department of Agriculture in 1997. Initially GM farming in South Africa involved growing GM cotton and at present over 80% of the national cotton crop is GM.

GM maize was approved for commercial release in South Africa in 1998 and initially comprised about 6 yellow maize hybrids.

GM soya beans were approved in South Africa in 2000 and by 2003 about 35% of the crop was GM.

In 2003, the following GM crops were planted in South Africa:

  • White maize - 140 000 hectares comprising 8% of the total crop
  • Yellow maize - 190 000 hectares constituting 20% of the total crop
  • Soya beans - 42 000 hectares which equals 35% of the total crop
  • the non-food crop of cotton - 28 000 hectares which represents 80% of the total crop

Before these GM food crops enter the market, they have to pass strict requirements specified by a number of international scientific agencies such as the World Health Organisation (WHO), the FAO (Food & Agricultural Organisation) and the Organisation for Economic Cooperation and Development (OECD). In South Africa GM foods and crops have to pass the stringent requirements of the GMO Act, No 15 of 1997.

Future products
The following GM products are being developed and may be produced in South Africa in the near future: Other varieties of maize, potatoes, tomatoes, sugar cane, other varieties of soya, wheat, cassava, melons, millet, sorghum, cowpeas, and sweet potatoes, which are resistant to plant pests, fungi and viruses, or have salt or drought resistant properties.

As of 1 April 2004, maize varieties that are resistant to corn borer and other plant pests have been released for animal feed and human consumption. Most of these maize varieties have also been approved in the USA, Japan, and the EU.

South Africa is at present the only country in Africa to plant GM crops commercially, but a number of other African states are already conducting field trials with such crops.

GM foods are, therefore, being grown and marketed in South Africa and it is likely that their use will increase in future.

Next week we will consider labelling of GM foods and the potential effects of GM foods on nature and consumers. (Dr I. V. van Heerden) (References: (AfricaBio (2004). Agricultural Biotechnology - Facts for Decision Makers, AfricaBio, Pretoria; Robinson C (2001). Genetic Modification Technology & Food, ILSI, Brussels)


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