Ben & Jerry's, the self-styled "all natural" ice cream manufacturer, has broken ranks with food giant Unilever amid controversy about GM ice cream.

The breach follows a report in The Independent on Sunday last week revealing concerns from scientists over the risk to health from a synthetically produced "anti-freeze" protein, using a GM process, which Unilever is trying to get approved in the UK.

A spokesperson for Ben & Jerry's said: "We would not dream of including anything like that in our products. One of the biggest problems is that we are affected by Unilever's actions even though they are nothing to do with the way that we behave. The fact that we are not using this GM ingredient shows that we are not following all of their decisions."

The company is owned by Unilever, as are Wall's and Birds Eye. Unilever has described the ingredient as an "exciting new technology that has potential benefits for ice cream, including the possibility of increased fruit content and lower fat content". It declined to comment on the details of its application, beyond stating, "We believe that it will provide some real consumer benefit but we have to go through the approval system, so we'll have to wait and see."

In a report to the Food Standards Agency (FSA), researchers from the Independent Science Panel warned: "Without long-term testing, we could be letting off an immunological time bomb." The FSA has confirmed that the submission is one of several that it has received. Its Advisory Committee on Novel Foods and Processes decides on Thursday whether to allow the application to go to the European Union for approval.

This comes as the bio-tech industry is taking advantage of free-trade rules to attempt to break into the European market, with dozens of applications to either grow or import GM produce, such as rice, potatoes, maize and sugar beet.

Peter Melchett, policy director of the Soil Association, said: "Ben & Jerry's is showing some very sound commercial judgement."