Growers have given a mixed reception to the idea of labelling food with its carbon footprint, after the government said it was consulting on such a move.
Defra warned that locally produced and organic food could have a higher environmental impact than imported product after publishing a report by Manchester Business School looking at the impact of different foods.
Growers were worried they would be penalised for using heat and fertiliser to boost yields and lengthen seasons.
"There is a danger that the hard work from our growers will go by the board," said NFU horticulture board chairman Richard Hirst. "Carbon labelling is a big can of worms and could also be a move away from food security."
The Soil Association was more upbeat and said carbon labelling could be good for organic sales. It claimed most organic fresh produce was kinder to the environment than its conventional counterparts.
"Organic farming is overall more energy efficient than non-organic mainly because it does not use nitrogen fertilisers, which are produced from petrochemicals in an energy-intensive process," said director Patrick Holden. "Typically organic farming is about 30% more energy efficient for producing the same quantity of food."
Importers thought the idea could benefit foreign growers. Amos Orr at Israeli importer Agrexco, said: "Israel is not far from the UK. Produce is moved by sea in very efficient craft."
David Flynn, financial director of Fyffes, said consumers might be surprised to learn how little carbon was emitted in the production of exotic fruit. But any additional labelling was likely to confuse shoppers, he said.
Defra said officials would meet the multiples in April to look at ways of labelling products with carbon costs.