Tesco and Aldi have both issued warnings to anyone who has bought fruit and vegetables from their shelves.
The supermarket giants are urging customers to wash any fruit or veg before eating it, amid fears it could have been dirtied by the Saharan desert dust cloud that swept across the Mediterranean earlier this month.
In the middle of March, Spanish authorities issued "extremely poor air quality ratings" for a large band of the country.
Now Tesco has said the dust has affected some of its Spanish crops. It has posted a notice on its website urging people to wash produce before eating, according to the Manchester Evening News.
It said: "Due to the recent winds from the Sahara Desert, a small amount of dust has settled on our Spanish crops. Please ensure you wash your fruit and veg products before enjoying. Thank you for supporting our growers and preventing food waste by continuing to buy these products."
Signs have also been spotted in Aldi stores, stating: "Please give your veg an extra rinse. Due to recent winds from the Sahara Desert, a small amount of dust may have settled in some of our packs. Thank you for supporting our growers and helping to reduce food waste by continuing to buy these products."
Eating sand or dust is at best unpleasant but at worst dangerous, as it can contain micro-organisms that can make us ill.
The dust cloud moved across Europe in mid March. People across the UK reported glowing orange skies.
At the time, Met Office meteorologist Dan Stroud said: "The dust in the atmosphere causes the light to be more refracted, so you get the dominance of the red and orange tinges of the spectrum."
The cloud formed when dust from the Sahara Desert was driven up into the air by a weather front dubbed Storm Celia by Spanish authorities. It was then pushed over the Mediterranean before covering parts of France and Spain.
Baffled Brits were "disgusted" when they saw their cars in the early hours of the morning and thought the rain was "really" dirty.
Dr Andy Whittamore - the clinical lead at Asthma UK - has warned of the risks posed by Saharan dust.
He said: "Toxic air can leave people struggling for breath and can cause wheezing, coughing, shortness of breath and even a life-threatening asthma attack," he said.
“Saharan dust could pose a serious risk to the 5.4 million people in the UK with asthma".
