A Suffolk seed firm is warning vegetable growers that courgettes grown from its seeds could cause stomach upsets and sickness if eaten.

Mr Fothergill’s is recalling a batch of its courgette seeds over fears produce could lead to stomach upsets.

The firm, based in Kentford, near Newmarket, issued the warning after discovering some of its own brand courgette seed packs could contain seeds leading to bitter tasting fruits.

It is believed the bitter taste comes from an unusually high level of cucurbitacins – which normally exist in small amounts – and could potentially lead to stomach cramps, diarrhoea and sickness if the vegetable is eaten.

In a statement, the firm said it was an “extremely rare” problem and stressed it was the first time it had faced the issue in more than 40 years of trading.

The statement read: “The incidence of this problem is extremely rare, but not unknown. It is not an issue listed by the Horticultural Trades Association, whose caution labelling guidelines we voluntarily and rigorously follow.

“It can come from issues with cross-pollination in the seed production cycle and is untraceable before growing out again for harvest.

“We have tracked the problem to one particular batch of seed which comes from a grower with the most meticulous growing and husbandry routines.”

The firm believes only its own brand courgette seed packs labelled “I” on the rear of the pack (near to the sow by date) are affected by the issue.

Those who believe they may have grown vegetables from the batch are asked to discard them, and those who have a packet of seeds to return for a replacement should contact the firm here.

The statement added: “Please be assured that we take every precaution to maintain the quality of our seed stock.

“In this instance we are withdrawing the rogue batch from all sales outlets and in-house stocks.”