Sources of GM food

The process of GM produces combinations of genetic material that is never made previously, including genes sequences that are completely synthesized in the laboratory, differing significantly from their the original DNA. This process alters the recombination sequences of the DNA and therefore induces positive changes like, tolerance to crops, better sensory attributes, to crops.

The sources of GM foods can be used for:

Consumption:A crop, such as a fruit or vegetable, that is genetically modified.
An ingredient for a food product:Food, take example, flour that comes from a GM crop, such as maize, and the GM DNA is still present in the food and can be identified.

GM processing aid:In cheese production, the gene for producing chymosin is inserted in bacteria, so the bacteria can produce chymosin. Only the bacteria are genetically modified and so the cheese is not GM-ed.

Animal feed:GM crops, such as maize, are used to feed animals which are later eaten, such as chickens. The GM material is not in the meat that we eat. There are also animal products, such as eggs and milk that come from animals fed on GM crops.

http://www.food.gov.uk/gmdebate/aboutgm/108106?view=GM%20Microsite