Genetically modified (GM) foods are foods derived from genetically modified organisms. Genetically modified organisms have had specific changes introduced into their DNA by genetic engineering, using a process of either Cisgenesis or Transgenesis. These techniques are much more precise than mutagenesis (mutation breeding) where an organism is exposed to radiation or chemicals to create a non-specific but stable change. Other techniques by which humans modify food organisms include selective breeding (plant breeding and animal breeding), and somaclonal variation.
GM foods were first put on the market in the early 1990s. Typically, genetically modified foods are transgenic plant products: soybean, corn, canola, and cotton seed oil. But animal products have also been developed. In 2006 a pig was controversially[1][2] engineered to produce omega-3 fatty acids through the expression of a roundworm gene.[3] Researchers have also developed a genetically-modified breed of pigs that are able to absorb plant phosphorus more efficiently, and as a consequence the phosphorus content of their manure is reduced by as much as 60%. [4]
Critics have objected to GM foods on several grounds, including perceived safety issues,[5] ecological concerns, and economic concerns raised by the fact that these organisms are subject to intellectual property law.
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Genetic modification involves the insertion or deletion of genes. In the process of Cisgenesis genes are artificially transferred between organisms that could be conventionally bred. In the process of Transgenesis genes from a different species are inserted, which is a form of horizontal gene transfer. In nature this can occur when exogenous DNA penetrates the cell membrane for any reason. To do this artificially may require attaching genes to a virus or just physically inserting the extra DNA into the nucleus of the intended host with a very small syringe, or with very small particles fired from a gene gun. However, other methods exploit natural forms of gene transfer, such as the ability of Agrobacterium to transfer genetic material to plants, and the ability of lentiviruses to transfer genes to animal cells.
The first commercially grown genetically modified whole food crop was a tomato (called FlavrSavr), which was modified to ripen without softening, by a Californian subsidiary of Monsanto called Calgene.[6] Calgene took the initiative to obtain FDA approval for its release in 1994 without any special labeling, although legally no such approval was required.[7] It was welcomed by consumers who purchased the fruit at a substantial premium over the price of regular tomatoes. However, production problems[6] and competition from a conventionally bred, longer shelf-life variety prevented the product from becoming profitable. A variant of the Flavr Savr was used by Zeneca to produce tomato paste which was sold in Europe during the summer of 1996.[8] The labeling and pricing were designed as a marketing experiment, which proved, at the time, that European consumers would accept genetically engineered foods.
Currently, there are a number of food species in which a genetically modified version exists.
| Food | Properties of the genetically modified variety | Modification | Percent Modified in US | Percent Modified in world |
|---|---|---|---|---|
| Soybeans | Resistant to glyphosate or glufosinate herbicides | Herbicide resistant gene taken from bacteria inserted into soybean | 89% | TBA |
| Corn, field | Resistant to glyphosate or glufosinate herbicides, Insect resistance - using Bt proteins some previously used as pesticides in organic crop production.
Vitamin-enriched corn derived from South African white corn variety M37W has bright orange kernels, with 169x increase in beta carotene, 6x the vitamin C and 2x folate.[9] || New genes added/transferred into plant genome. || 60% || TBA |
|||
| Cotton (cottonseed oil) | Pest-resistant cotton | Bt crystal protein gene added/transferred into plant genome | 83% | 62% |
| Hawaiian papaya | Variety is resistant to the papaya ringspot virus.[10] | New gene added/transferred into plant genome | +50% | TBA |
| Tomatoes | Variety in which the production of the enzyme polygalacturonase (PG) is suppressed, retarding fruit softening after harvesting.[11] | A reverse copy (an antisense gene) of the gene responsible for the production of PG enzyme added into plant genome | Taken off the market due to commercial failure. | None |
| Potatoes | Amflora variety produces waxy potato starch composed almost exclusively of the amylopectin component of starch.[12] | The gene for granule bound starch synthase (GBSS) (the key enzyme for the synthesis of amylose) was switched off by inserting antisense copy of the GBSS gene. | Amflora will be produced solely under contract farming conditions and not made available on the general market. | TBA |
| Rapeseed (Canola) | Resistance to herbicides (glyphosate or glufosinate), high laurate canola[13] | New genes added/transferred into plant genome | 75% | TBA |
| Sugar cane | Resistance to certain pesticides, high-sucrose cane. | New genes added/transferred into plant genome | TBA | TBA |
| Sugar beet | Resistance to glyphosate, glufosinate herbicides | New genes added/transferred into plant genome | TBA | TBA |
| Sweet corn | Produces its own bioinsecticide (Bt toxin) | Gene from the bacterium Bacillus thuringiensis added to the plant. | TBA | TBA |
| Rice | Genetically modified to contain high amounts of Vitamin A (beta-carotene) | "Golden rice" Three new genes implanted: two from daffodils and the third from a bacterium | TBA | TBA |
In addition, various genetically engineered micro-organisms are routinely used as sources of enzymes for the manufacture of a wide variety of processed foods. These include alpha-amylase from bacteria, which converts starch to simple sugars, chymosin from bacteria or fungi that clots milk protein for cheese making, and pectinesterase from fungi which improves fruit juice clarity.[14]
Between 1997 and 2005, the total surface area of land cultivated with GMOs had increased by a factor of 50, from 17,000 km2 (4.2 million acres) to 900,000 km2 (222 million acres).
Although most GM crops are grown in North America, in recent years there has been rapid growth in the area sown in developing countries. For instance in 2005 the largest increase in crop area planted to GM crops (soybeans) was in Brazil (94,000 km2 in 2005 versus 50,000 km2 in 2004.)[15] There has also been rapid and continuing expansion of GM cotton varieties in India since 2002. (Cotton is a major source of vegetable cooking oil and animal feed.) It is predicted that in 2008/9 32,000 km2 of GM cotton will be harvested in India (up more than 100 percent from the previous season).
Indian national average cotton yields of GM cotton were seven times lower in 2002, because the parental cotton plant used in the genetic engineered variant was not well suited to the climate of India and failed. The publicity given to transgenic trait Bt insect resistance has encouraged the adoption of better performing hybrid cotton varieties, and the Bt trait has substantially reduced losses to insect predation. Though controversial and often disputed, economic and environmental benefits of GM cotton in India to the individual farmer have been documented.[16][17]
In 2003, countries that grew 97% of the global transgenic crops were the United States (53%), Argentina (17%), Brazil (11%), Canada (6%), India (4%), China (3%), Paraguay (2%) and South Africa (1%).[18] The Grocery Manufacturers of America estimate that 75% of all processed foods in the U.S. contain a GM ingredient[19] . In particular, Bt corn, which produces the pesticide within the plant itself, is widely grown, as are soybeans genetically designed to tolerate glyphosate herbicides. These constitute "input-traits" are aimed to financially benefit the producers, have indirect environmental benefits and marginal cost benefits to consumers.
In the US, by 2006 89% of the planted area of soybeans, 83% of cotton, and 61% corn were genetically modified varieties. Genetically modified soybeans carried herbicide-tolerant traits only, but maize and cotton carried both herbicide tolerance and insect protection traits (the latter largely the Bacillus thuringiensis Bt insecticidal protein). In the period 2002 to 2006, there were significant increases in the area planted to Bt protected cotton and maize, and herbicide tolerant maize also increased in sown area.[20]
Some scientific studies have claimed that genetically modified varieties of plants do not produce higher crop yields than normal plants.[21] However, other scientific studies dispute these claims.[citation needed]
One study by Charles Benbrook, Chief Scientist of the Organic Center, found that genetically engineered Roundup Ready soybeans do not increase yields (Bendrook, 1999). The report reviewed over 8,200 university trials in 1998 and found that Roundup Ready soybeans yielded 7-10% less than similar natural varieties. In addition, the same study found that farmers used 5-10 times more herbicide (Roundup) on Roundup Ready soybeans than on conventional ones.[22]
The United States and Canada do not require labeling of genetically modified foods.[23] However in certain other regions, such as the European Union, Japan, Malaysia and Australia, governments have required labeling so consumers can exercise choice between foods that have genetically modified, conventional or organic origins.[24][25] This requires a labeling system as well as the reliable separation of GM and non-GM organisms at production level and throughout the whole processing chain.[24][25] Research suggests that this may prove impossible.[citation needed]
For traceability, the OECD has introduced a "unique identifier" which is given to any GMO when it is approved. This unique identifier must be forwarded at every stage of processing.[citation needed] Many countries have established labeling regulations and guidelines on coexistence and traceability. Research projects such as Co-Extra, SIGMEA and Transcontainer are aimed at investigating improved methods for ensuring coexistence and providing stakeholders the tools required for the implementation of coexistence and traceability.[citation needed]
Testing on GMOs in food and feed is routinely done using molecular techniques like DNA microarrays or qPCR. These tests can be based on screening genetic elements (like p35S, tNos, pat, or bar) or event-specific markers for the official GMOs (like Mon810, Bt11, or GT73). The array-based method combines multiplex PCR and array technology to screen samples for different potential GMOs [26], combining different approaches (screening elements, plant-specific markers, and event-specific markers).
The qPCR is used to detect specific GMO events by usage of specific primers for screening elements or event-specific markers. Controls are necessary to avoid false positive or false negative results. For example, a test for CaMV is used to avoid a false positive in the event of a virus contaminated sample.
A Price Look-Up code beginning with the digit 8 indicates genetically modified food. [3]
While it is evident that there is a food supply issue; the question is whether GM can solve world hunger problems. Several scientists argue that in order to meet the demand for food in the developing world, a second green revolution with increased use of GM crops is needed.[27] Others argue that there is more than enough food in the world and that the hunger crisis is caused by problems in food distribution and politics, not production.[28][29] Recently some critics have changed their minds on the issue with respect to the need for additional food supplies.[30]
“Genetic modification is analogous to nuclear power: nobody loves it, but climate change has made its adoption imperative,” says economist Paul Collier of Oxford University. "Declining genetic modification makes a complicated issue more complex. Genetic modification offers both faster crop adaptation and a biological, rather than chemical, approach to yield increases."[31]
On the other hand, many believe that GMF’s have not been a success and that we should devote our efforts and money into another solution. “We need biodiversity intensification that works with nature’s nutrient and water cycles, not against them,” says Vandana Shiva. Shiva, the founder of Navdanya, the movement of 500,000 seed keepers and organic farmers in India, argues that GMF’s have not increased yields. Recently, Doug Gurian-Sherman, a member of the Union of Concerned Scientists, a nonprofit science advocacy group, published a report called “Failure to Yield”, in which he stated that in a nearly 20 year record, genetically engineered crops have not increased yields. [32]
Taking a more technical approach, GMF’s help farmers produce, despite the odds or any environmental barriers. “While new technology must be tested before it is commercially released, we should be mindful of the risks of not releasing it at all,” says Per Pinstrup-Andersen professor of Food, Nutrition and Public Policy at Cornell University. Per Pinstrup-Anderson argues, “Misguided anti-science ideology and failure by governments to prioritize agricultural and rural development in developing countries brought us the food crisis.” He clearly states the challenge we face is not the challenge of whether we have enough resources to produce, but whether we will change our behavior. [33]
Traditionally, farmers in all nations saved their own seed from year to year. Allowing to follow this practice with genetically modified seed would result in seed developers losing the ability to profit from their breeding work. Therefore, genetically-modified seed are subject to licensing by their developers in contracts that are written to prevent farmers from following this traditional practice.[43] Many objections to genetically modified food crops are based on this change.
Enforcement of patents on genetically modified plants is often contentious, especially because of gene flow. In 1998, 95-98 percent of about 10 km2 planted with canola by Canadian farmer Percy Schmeiser were found to contain Monsanto Company's patented Roundup Ready gene although Schmeiser had never purchased seed from Monsanto.[44] The initial source of the plants was undetermined, and could have been through either gene flow or intentional theft. However, the overwhelming predominance of the trait implied that Schmeiser must have intentionally selected for it. The court determined that Schmeiser had saved seed from areas on and adjacent to his property where Roundup had been sprayed, such as ditches and near power poles.[45]
Although unable to prove direct theft, Monsanto sued Schmeiser for piracy since he knowingly grew Roundup Ready plants without paying royalties(Ibid). The case made it to the Canadian Supreme Court, which in 2004 ruled 5 to 4 in Monsanto’s favor.[44][45] The dissenting judges focused primarily on the fact that Monsanto's patents covered only the gene itself and glyphosate resistant cells, and failed to cover transgenic plants in their entirety. All of the judges agreed that Schmeiser would not have to pay any damages since he had not benefited from his use of the genetically modified seed.
In response to criticism, Monsanto Canada's Director of Public Affairs stated that "It is not, nor has it ever been Monsanto Canada's policy to enforce its patent on Roundup Ready crops when they are present on a farmer's field by accident...Only when there has been a knowing and deliberate violation of its patent rights will Monsanto act."[46]
Future envisaged applications of GMOs are diverse and include drugs in food, bananas that produce human vaccines against infectious diseases such as Hepatitis B,[47] metabolically engineered fish that mature more quickly, fruit and nut trees that yield years earlier, foods no longer containing properties associated with common intolerances, and plants that produce new plastics with unique properties.[48] While their practicality or efficacy in commercial production has yet to be fully tested, the next decade may see exponential increases in GM product development as researchers gain increasing access to genomic resources that are applicable to organisms beyond the scope of individual projects. Safety testing of these products will also, at the same time, be necessary to ensure that the perceived benefits will indeed outweigh the perceived and hidden costs of development. Plant scientists, backed by results of modern comprehensive profiling of crop composition, point out that crops modified using GM techniques are less likely to have unintended changes than are conventionally bred crops.[49][50]
In the United States, the FDA Center for Food Safety and Applied Nutrition must approve the nutritional characteristics of GMO foods on the basis of comparability to conventionally-produced foods. The table below shows the foods that had received FDA approval as of 2002.[51]
A 2008 review published by the Royal Society of Medicine noted that GM foods have been eaten by millions of people worldwide for over 15 years, with no reports of ill effects.[52] Similarly a 2004 report from the US National Academies of Sciences stated: "To date, no adverse health effects attributed to genetic engineering have been documented in the human population."[5] Worldwide, there are a range of perspectives within non-governmental organizations on the safety of GM foods. For example, the US pro-GM pressure group AgBioWorld has argued that GM foods have been proven safe,[53] while other pressure groups and consumer rights groups, such as the Organic Consumers Association,[54] and Greenpeace[55] claim the long term health risks which GM could pose, or the environmental risks associated with GM, have not yet been adequately investigated.
In 1998 Rowett Research Institute scientist Árpád Pusztai reported that consumption of potatoes genetically modified to contain lectin had adverse intestinal effects on rats.[56] Pusztai eventually published a paper, co-authored by Stanley Ewen, in the journal, The Lancet. The paper claimed to show that rats fed on potatoes genetically modified with the snowdrop lectin had unusual changes to their gut tissue when compared with rats fed on non modified potatoes.[57] The experiment has been criticised by other scientists on the grounds that the unmodified potatoes were not a fair control diet and that all the rats may have been sick, due to them being fed a diet of only potatoes.[58]
In 2010 three scientists published a statistical re-analysis of three feeding trials that had previously been published by others as establishing the safety of genetically modified corn.[59][60][61] The new article claimed that their statistics instead showed that the three patented crops (Mon 810, Mon 863, and NK 603) developed and owned by Monsanto cause liver, kidney, and heart damage in mammals.[62] A previous re-analysis of part of this data by the same group of scientists was assessed by a panel of independent toxicologists in a study funded by Monsanto and published in the journal Food and chemical toxicology, the reviewers reported that the study was statistically flawed and providing no evidence of adverse effects.[63]
As of January 2009 there has only been one human feeding study conducted on the effects of genetically modified foods. The study involved seven human volunteers who had previously had their large intestines removed. These volunteers were to eat GM soy to see if the DNA of the GM soy transferred to the bacteria that naturally lives in the human gut. Researchers identified that three of the seven volunteers had transgenes from GM soy transferred into the bacteria living in their gut, though none of the gene transfers occurred during the course of the study. In volunteers with complete digestive tracts, the transgene did not survive passage through intact gastrointestinal tract.[64] Anti-GM advocates believe the study should prompt additional testing to determine its significance.[65]
A study on the possible effects of feeding genetically modified feeds to animals found that there was no significant differences in the safety and nutritional value of feedstuffs containing material derived from genetically modified plants.[66] Specifically, the study noted that no residues of recombinant DNA or novel proteins have been found in any organ or tissue samples obtained from animals fed with GMP plants.
In the mid 1990s Pioneer Hi-Bred tested the allergenicity of a transgenic soybean that expressed a Brazil nut seed storage protein in hope that the seeds would have increased levels of the amino acid methionine. The tests (radioallergosorbent testing, immunoblotting, and skin-prick testing) showed that individuals allergic to Brazil nuts were also allergic to the new GM soybean.[67] Pioneer has indicated that it will not develop commercial cultivars containing Brazil nut protein because the protein is likely to be an allergen.[68]
Cons and Pros of GM food.
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