A team of New Zealand researchers have bred genetically modified (GM) dairy cow that produces milk less likely to cause allergic reactions.

Making use of a process called RNA-interference, the researchers altered the genes of the cow to enable it to produce milk rich in a protein that used in several food products but lacking in a component that is responsible for causing allergies in humans

The milk produced by the genetically engineered cow contains higher levels of the casein protein, which could increase the levels of calcium milk. At the same time, the milk from the GM cow lacks a component in milk whey protein called beta-lactoglobulin, which causes allergies.

Around 2-3 per cent of infants in the developed countries are allergic to cows' milk proteins. The new study will allow baby formula makers to make products that will lack allergic components.

But, some experts are concerned over safety and environmental affects of milk from GM animals.

Director William Hallman, of the food policy institution at Rutgers University said, "Could you clone a breeding stock that would allow for a herd with milk of this type? There are lots of issues about what might happen in the next generation."

But, the researchers said that the successful study indicated that the technique could also be used to alter other traits in livestock.