Fears have been expressed that bakers will end up footing the bill if the government goes ahead with plans to fortify flour to increase pregnant women's uptake of folic acid.
Folate, which protects against neural tube defects in newborn babies, is an expensive ingredient in itself, says Alex Waugh, director general of the National Association of British and Irish Millers.
However, other costs could also be incurred if fortification became mandatory for all breads, particularly wholemeal, he warns.
Currently, the bread and flour regulations require the mandatory fortification of brown and white bread flour with calcium, iron and B vitamins, he said. If folate only had to be added to brown and white bread, it could simply be added into a prepared mix along with these other ingredients, he says.
However, adding folate to other flours such as wholemeal, which are not currently fortified, could mean "new hoppers, new flour lines and different packaging", which could be complicated and costly, he claims.
"No doubt we're going to have an argument over who's going to pay for it." Organic producers are also unhappy with the proposals, he claims.
Chris Whitehouse, md of industry lobbyist the Whitehouse Consultancy, also questions mandatory fortification: "Before embarking on a campaign of compulsory mass medication of up to 60m people, the Food Standards Agency (FSA) should first satisfy itself that it has done all in its power to promote folate intake through improved diet and that it has actively promoted the benefits of supplementation to women trying to conceive."
An FSA spokeswoman says: "We are looking to make a recommendation to government ministers at the Department of Health in October, and they will have the final say. The theoretical risk of flour fortification is that if old people overdose on folic acid, then it can mask the signs of anaemia and B12 deficiency, which can lead to neurological damage."
The US, Canada and Chile already fortify flour with folic acid and these countries have seen a 27-50% decline in pregnancies affected by neural tube defects, she says.