GM, or genetically modified, food, involves altering a plant, animal or micro-organism's genes or inserting one from another organism – that is, a living thing. Genes carry the instructions for all the characteristics that an organism inherits. They are made up of DNA.
Sometimes the term 'biotechnology' is used to describe genetic modification. This also has a wider meaning of using micro-organisms or biological techniques to process waste or produce useful compounds, such as vaccines.
How it's being usedPeople have been breeding animals and new varieties of plants for many hundreds of years to develop or avoid certain qualities. Examples include racehorses that are bred to be faster and stronger, and roses, bred to give a wider range of colours and to make them more resistant to disease. Over many generations, sometimes for thousands of years, the world's main food crops have been selected, crossed and bred to suit the conditions they are grown in and to make them tastier.
For example, cattle are bred according to whether they are for beef or dairy herds. Most of today's dairy cattle are very different from the cattle that were originally domesticated. Over the years, dairy herd breeding has focused on increasing milk yield and on improving the quality of the milk.
But whereas traditional methods involve mixing thousands of genes, genetic modification allows just one individual gene, or a small number of genes, to be inserted into a plant, animal or micro-organism (such as bacteria), to change it in a pre-determined way. Through genetic modification, genes can also be 'switched' on or off to change the way a plant or animal develops.
For example, herbicides are used to kill weeds in fields of crops but they can also affect the growth of the crops they are intended to protect. By using genetic modification, a gene with a particular characteristic, such as resistance to a specific herbicide, can be introduced into a crop plant. When that herbicide is sprayed on the field to kill the weeds, it will not hinder the growth of the crops.
Similarly, genetic modification can be used to reduce the amount of pesticide needed by altering a plant's DNA so it can resist the particular insect pests that attack it. Genetic modification can also be used to give crops immunity to plant viruses or to improve the nutritional value of a plant. In animals intended for food, genetic modification could potentially increase how fast and to what size they grow.
Genetic modification allows plants, animals and micro-organisms to be produced with specific qualities more accurately and efficiently than through traditional methods. It also allows genes to be transferred from one species to another to develop characteristics that would be very difficult or impossible to achieve through traditional breeding. For example, genes can be introduced from one plant to another plant, from a plant to an animal, or from an animal to a plant. Transferring genes between plants and animals is a particular area of debate.
What is DNA?DNA stands for deoxyribonucleic acid. It is the genetic material contained in the cells of all living things and it carries the information that allows organisms to function, repair and reproduce themselves.
Every cell of plants (see illustration below), micro-organisms (such as bacteria), animals, and people contain many thousands of different genes, which are made of DNA. These genes determine the characteristics, or genetic make-up, of every living thing, including the food we eat. When we eat any food, we are eating the genes and breaking down the DNA present in the food.
DNA is made up of two separate strands of what are called 'nucleotides'. These are the building blocks of DNA and are twisted around each other in a double helix structure (see illustration below). The identity of a gene and the function it performs are determined by the number of nucleotides and the particular order in which they are strung together on chromosomes – this is known as the 'sequence' of the gene. Chromosomes are the cell structures that carry the DNA.
How are GM foods assessed for safety?Any GM foods intended for sale in the European Union are subject to a rigorous safety assessment, which is the responsibility of the European Food Safety Authority (EFSA).
However, the final decision for authorisation still rests with Member States, which vote on each GM food. In the event of an inconclusive vote, the Council of Ministers votes, and if they cannot agree the final decision rests with the European Commission.
EFSA is responsible for publishing information concerning applications submitted under this legislation. Further details can be found on the EFSA website.
The Food Standards Agency is the UK authority named in the European legislation, and is advised on both GM and novel foods by an independent body of experts called the Advisory Committee on Novel Foods and Processes (ACNFP) and on GM animal feed by the Advisory Committee on Animal Feedingstuffs (ACAF). The ACNFP is responsible for assessing the safety of novel and GM food, and ACAF is responsible for assessing the safety of GM feed.
The Board of the Food Standards Agency stated in June 2000 that it was satisfied that the safety assessment procedures for GM foods were sufficiently robust and rigorous to ensure that approved GM foods were as safe as their non-GM counterparts, and posed no additional risk to the consumer.
Each GM food is assessed for safety, including its toxicological, nutritional and allergenic potential, on a case-by-case basis before it can be approved for marketing.
The Agency supports consumer choice. We recognise that some people will want to choose not to buy or eat genetically modified (GM) foods, however carefully they have been assessed for safety.
In 2003 the Agency supported a range of initiatives to independently assess public opinion on the acceptability of GM food and how this relates to consumer choice. This formed the Agency's contribution to the Government's public debate on GM. Details of the various activities we supported can be found on our GM food debate website and were summarised in our submission to the Government's GM public debate.
How is GM used in food production?Genetic modification can be used in a number of ways in food production. These range from modifying the raw ingredients to using genetic modification during processing.
When genetic modification is used as a part of the production process, as described in 4 below, the GM material does not end up in the food on our plates. This is similar to other processing techniques, so, for example, when a food processor is used for slicing, no part of the processor ends up in the meal we eat.
These are the different ways that genetic modification can be used in food production:
1. GM food: A crop, such as a fruit or vegetable, or an animal can be genetically modified. (However, no animal or human genes, or GM animals, have been approved for use in GM food in the EU.)
2. GM ingredients: Food that comes from a GM crop, such as maize, can be processed, for example into flour, and the GM DNA is still present in the food and can be identified.
3. ‘GM-derived’ ingredients: Food can come from a GM crop but the DNA can be processed out of the final product – this is called 'GM-derived'. An example of this is soy oil, which is made from GM soya beans. The processing breaks up the DNA so that it can no longer be identified either as GM DNA or conventional DNA in the final oil because it has been broken down into small fragments containing nucleotides – these are DNA building blocks. Therefore, soy oil from GM soya beans cannot be distinguished from soy oil from conventional beans.
4. GM processing aid: A GM organism can also be used to make a product without GM material being present in the ingredients or in the final product. In this case the GM organism is a 'processing aid'. One example is hard cheese production. The enzyme chymosin is the active ingredient of rennet, which is used to curdle milk. Traditionally, rennet has been taken from calves’ stomachs, but the demand for cheese is greater than the number of calves available and the chymosin does not always produce consistent batches of cheese. Today, the gene responsible for producing chymosin is inserted in bacteria, so the bacteria make the chymosin instead of using traditional rennet. Only the bacteria are genetically modified, not the chymosin, and so the cheese has no GM content because the bacteria are not part of the cheese.
5. GM ingredients in animal feed: GM crops, such as maize, are also used to feed animals that are later eaten, such as chickens. There are also animal products, such as eggs and milk, which come from animals fed on GM crops. Functioning GM DNA is not, however, in the meat that we eat or these animal products. See the following two paragraphs that explain what happens to DNA in our bodies and during food processing.
How does processing affect the DNA in foods?
DNA is broken up in the same way that food processing can alter or destroy other characteristics of food ingredients, such as texture, during manufacturing. Processing includes all the stages involved in getting food ready for us to eat, from refining raw materials to cooking in our homes.
What happens when people eat GM food?
Human beings have always eaten plants and animals, which means we have always eaten their DNA without it causing any health problems. Given that GM DNA is still DNA, eating it should not pose any greater risk than eating non-GM DNA. Indeed, no one has ever been reported as suffering from illness because the food they had eaten had been genetically modified.
When someone eats GM food it is processed in the same way as non-GM food. When we eat any food, our digestive systems break down the tissue, the proteins, and the DNA in the food. The DNA in GM food has the same structure as non-GM DNA and is broken down in the same way. Most DNA that is consumed, whether GM or not, is broken down in our stomachs and intestines.
Sometimes, the DNA from the food we eat isn't broken down. However, it is unlikely that this DNA will become part of our genetic material by passing into our cells – any non-human DNA should simply be broken down in the cell.
Will the label tell me if the food is GM?The Agency supports consumer choice. We recognise that some people will want to choose not to buy or eat GM foods, however carefully they have been assessed for safety.
In the EU, if a food contains or consists of genetically modified organisms (GMOs), or contains ingredients produced from GMOs, this must be indicated on the label. For GM products sold 'loose', information must be displayed immediately next to the food to indicate that it is GM.
On 18 April 2004, new rules for GM labelling came into force in all EU Member States. These cover all GM food and animal feed, regardless of the presence of any GM material in the final product.
This means products such as flour, oils and glucose syrups have to be labelled as GM if they are from a GM source. Products produced with GM technology (cheese produced with GM enzymes, for example) do not have to be labelled.
Products such as meat, milk and eggs from animals fed on GM animal feed also don't need labelling.
Any intentional use of GM ingredients at any level must be labelled. But there is no need to label small amounts of approved GM ingredients (below 0.9% for approved GM varieties) that are accidentally present in a food.