A complaint to trading standards officers in Scotland has led to an industry body issuing a new description of what constitutes a "new potato".
South Ayrshire Council was asked to investigate whether new potatoes were stored for long periods before sale.
It found that in some cases newly-harvested potatoes were stored for up to seven months before being sold.
The Potato Council has now drawn up an industry standard definition after the council raised its concerns.
The traditional description of a new potato is that it has been specially grown and harvested early, with a thin skin or one you can rub off with a finger.
The Potato Council's new industry standard description states that new potatoes are destined for consumer purchase soon after harvest.
Soon is defined as the period the potatoes can reasonably be expected to retain their "specific properties" if stored correctly.
This time period allows for distribution time and short-term holding of stock to meet demand.
The new guidelines also states that the new potato should have "an immature thin or scraping skin" and be "an appropriate variety".
The new description and guidelines will now be considered by a dedicated group including the Food Standards Agency Scotland, South Ayrshire Council, the Potato Council and other industry bodies.
Caroline Evans from the Potato Council said: "To meet demand for quick and tasty potatoes, we have lost the seasonality.
"Our description of a new potato means customers know they're enjoying potatoes at their seasonal best - and if your supermarket adopts the description, you can be sure of what you're buying."
South Ayrshire Council's investigation was prompted by a complaint from George Norris from Ayr.
He said he believed potatoes on sale as "new" had been stored for prolonged periods after harvesting.
To find out exactly what was happening locally, the council monitored the sale of new potatoes from Aldi, Asda, Co-op, Iceland, Lidl, Morrisons, Sainsbury and Tesco between December 2012 and March this year.
It also asked for planting and harvesting information.
In each of the 24 samples given by the six retailers who responded, trading standards officials were told that the potatoes had been harvested quite some time before going on sale.
In one case, potatoes harvested in August 2012 did not go on sale until March 2013, but were still described as new.
Officials were also concerned that the way some loose potatoes were displayed in supermarkets could suggest they had been freshly dug, when that was not the case.
South Ayrshire Councillor John McDowall said the authority had been right to take its concerns to industry bodies.
"We hope the outcome of our investigation will ensure consumer confidence in what is one of the most basic items on our shopping lists," he said.
"When we buy new potatoes, we have an expectation that they will have been lifted out of the ground shortly before going on sale.
"With the introduction of the new industry standard description, we can all hope that we'll get exactly that when we buy new potatoes in the future."
Mr McDowall said it was now up to retailers to adopt the new standard to ensure customers were not misled.
Mr Norris, whose complaint to the council led to the new definition, said he was "very pleased" to have a "positive outcome".
He added: "I will follow any developments with interest."