Much of the produce had been stored under lorries and was exposed to dust and pollution, said Salim Ali bin Zayed, acting head of the market section at Dubai Municipality.
“Selling food items unsuitable for human consumption was not the only problem, but also they were cooking food and selling it to labourers,” he added.
The food was part of nearly 16,500 tonnes of goods seized from illegal markets as part of an official crackdown this year. Much of it had been picked up from dumpsters.
The UAE has been witnessing a recent increase in instances of food fraud. Shortly before the markets discovery, police in Ras Al Khaimah raided a factory that was found to be selling expired meat.
Food officials in the northern emirate had discovered violations being committed by managers at the factory, which has a licence to manufacture mortadella and sausages out of processed frozen chicken.
"The factory management proved to have manipulated the validity dates of their meat products by repacking them in new plastic bags and cans with revised dates, and offering them for sale," said Brigadier Abdullah Ali Menakhas, director of RAK Police’s criminal investigations department.
A team from the organised crimes section of the police, along with health inspectors from the municipality, raided the factory and found significant quantities of expired meat products.
"Large amounts of bags and cans with manipulated dates have also been seized,” Brig. Menakhas added.
The suspects immediately confessed to manufacturing and selling expired meat products. They have since been charged under laws governing commercial fraud, racketeering and endangering public health.
The police said the goods were seized before they could be sold the the public.
In January, a butcher in Abu Dhabi was ordered to close for selling out-of-date meat as fresh meat.
Abu Dhabi Food Control Authority said that Al Fawz Butchery had failed to comply with health and safety requirements.
Thamer Al Qasimi, acting director of communications and community service, said the management had failed to rectify the situation following warnings.
Inspectors had fined the butcher twice before the authority ordered its closure.