German scientists are envisioning an enhanced version of, "Eat your vegetables - they're good for you!" They've developed a tomato plant with a higher portion of a health-promoting protein in the edible part of the plant - the tomato.

The researchers are excited about their technique, saying the tomatoes are a "safer" genetically modified organism, GMO.

The plant has been engineered in such a way that its genes are prevented from passing to other crops – one of the major concerns people have had about GMOs.

Lead researcher, Dr. Ralph Bock, at the Institute of Plant Biochemistry and Biotechnology, says their method ensures the genes stay within the plant.

Instead of introducing a gene for a particular trait into a plant's nuclear DNA, the coding sequence is inserted into small cellular components known as plastids.

In this case, the researchers used the chloroplasts, the centres where plants manufacture energy.

The DNA in chloroplasts, unlike nuclear DNA, isn't transmitted in pollen. So this eliminates the possibility that the modified plant's genetic material might contaminate other crops or pass undesirable traits to weeds.

The scientists envision a future with fruits and vegetables containing substantially more vitamins. They also plan to develop plants that contain vaccines in their fruit for oral immunization.

The team reported its work in Nature Biotechnology.