The Use of GM Crops in Developing Countries
Food safety
4.43 Given the previous arguments, a reasonable interpretation of the precautionary approach should also be applied when assessing the safety of GM crops that are intended for human consumption. In this context, we welcome the use of the concept of ‘substantial equivalence’ as an essential part of safety assessments of GM crops. This concept, which has been endorsed by the World Health Organization (WHO) and the FAO/WHO Codex Alimentarius Commission, involves comparing the GM crop in question to its closest conventional counterpart.43 The purpose of the procedure is to identify similarities and differences between a GM crop and a comparator which has a history of safe use. Although previous interpretations of the concept viewed ‘substantial equivalence’ as an endpoint in safety assessment,44 the current interpretation favours the concept as a framework for a comparative approach.45 The comparison does not aim to establish absolute safety, which is impossible to attain for any type of food. Rather, it should be seen as the first step in identifying whether it is safe for human consumption. Although the approach is not infallible, it is useful for identifying intended or unintended differences which might require further safety assessments (see Box 4.2).46
4.44 The concept of substantial equivalence has been applied successfully to crops produced by other forms of contemporary plant breeding, such as mutation breeding (see paragraph 3.8). With regard to assessing risks that are specific to GM crops, we have already seen that the technique often involves the introduction of genetic material from other species. Risks may also arise from the use of gene sequences from some plant viruses to facilitate the expression of an inserted gene (see paragraph 3.10).
4.45 Fears have been expressed that viral promoters could produce new viruses that would affect humans. However, only a small part of a plant virus is used (usually the 35S promoter from the cauliflower mosaic virus). Additionally, viruses usually infect only a very narrowly defined range of species. It is therefore unlikely that viruses that are adapted to infect Brassicas would infect humans.47 Another concern is that plant viruses may produce new viruses in humans by recombination with remnants of viral DNA sequences which exist in human DNA. However, research has shown that there are significant natural barriers to such a process.48 Indeed humans have eaten virally infected plants for millennia and there is no evidence that new viruses have been created as a consequence.49
4.46 There are also questions about whether foreign genetic material that has been introduced into a GM crop will be absorbed by the body. When humans eat plants or animals, they also eat DNA. This also applies to GM crops. However, the fact that such crops have been
Footnotes42 European Commission (2000) Communication from the Commission on the Precautionary Principle COM(2000) 1, Summary p6. See also Section 6.3 of this Communication.
43 FAO and WHO (2000) Safety Aspects of Genetically Modified Foods of Plant Origin Report of a Joint FAO/WHO Expert Consultation on Foods Derived from Biotechnology, WHO, Geneva, Switzerland, 29 May - 2 June 2000 (Geneva: WHO), paragraph 4.4.
44 See OECD (1993) Safety Evaluations of Foods Derived by Modern Biotechnology: Concepts and Principles (Paris: OECD).
45 GM Science Review (2003) First Report (London), p45; FAO and WHO (2000) Safety Aspects of Genetically Modified Foods of Plant Origin Report of a Joint FAO/WHO Expert Consultation on Foods Derived from Biotechnology, WHO, Geneva, Switzerland, 29 May - 2 June 2000 (Geneva: WHO), paragraph 4.4.
46 The European Network on Safety Assessment of Genetically Modified Food Crops (ENTRANSFOOD) incorporates a major cluster of EC-sponsored research projects and is set to publish a forthcoming report. The coordinator, H Kuiper concluded in a recent paper, “When evaluating a new or GM crops variety, comparison with available data on the nearest comparator, as well as with similar varietites on the market, should form the initial part of the assessment procedure”. See Kok EJ and Kuiper HA (2003) Comparitive safety assessment for biotech crops, Trends Biotechnol 21: 439.
47 Royal Society (2002) Genetically Modified Plants for Food Use and Human Health - an update (London: Royal Society), p8.
48 Worobey M and Holmes E (1999) Evolutionary aspects of recombination in RNA viruses, J Gen Virol 80: 2535–44; Aaziz R and Tepfer M (1999) Recombination in RNA viruses and in virus-resistant transgenic plants, J Gen Virol 80: 1339–46.
49 Royal Society (2002) Genetically Modified Plants for Food Use and Human Health - an update (London: Royal Society), p9. This Report also discusses other implications of the use of viral DNA in plants, relating to the use of the CaMV 35S promoter, which functions in a wide variety of species, and the possibility that viral DNA may activate so called transposable elements which are already present in the human genome. However, the Report concludes that risks to human health associated with the use of specific viral DNA sequences in GM crops are negligible.
50 FAO and WHO (2000) Safety Aspects of Genetically Modified Foods of Plant Origin Report of a Joint FAO/WHO Expert Consultation on Foods Derived from Biotechnology, WHO, Geneva, Switzerland, 29 May - 2 June 2000 (Geneva: WHO), p11.
51 FAO and WHO (2000) Safety Aspects of Genetically Modified Foods of Plant Origin Report of a Joint FAO/WHO Expert Consultation on Foods Derived from Biotechnology, WHO, Geneva, Switzerland, 29 May - 2 June 2000 (Geneva: WHO), p11.
52 FAO and WHO (2000) Safety Aspects of Genetically Modified Foods of Plant Origin Report of a Joint FAO/WHO Expert Consultation on Foods Derived from Biotechnology, WHO, Geneva, Switzerland, 29 May - 2 June 2000 (Geneva: WHO); Royal Society (2002) Genetically Modified Plants for Food Use and Human Health - an update (London: Royal Society).