Just past noon at the Dayanglu Market south-east of Beijing, merchants were tossing vegetables back into giant container trucks and moving meat back into storage freezers ahead of a mid-afternoon deadline for the market to undergo a thorough disinfection.

As more coronavirus cases linked to wholesale markets emerge in the Chinese capital, the local authorities have embarked on extensive disinfection and mass testing of the entire food supply chain - from suppliers to logistics workers and even restaurant staff.

Since a coronavirus outbreak surfaced last week at a produce wholesale market in south-west Beijing, 11 similar facilities have been shut, with stallholders and workers made to undergo tests for the virus.

The market closures have raised questions about Beijing's food security, and the authorities have been keen to keep the residents fed by decentralising suppliers to smaller wholesale markets like Dayanglu.

In a bid to alleviate fears about food safety, all markets will undergo deep cleaning and disinfection, while food handlers - from delivery truck drivers and produce sellers to restaurant workers - have been ordered to undergo testing.

With Xinfadi - where the new outbreak started - and other larger markets shut, some suppliers are shifting their produce to the 326,000 sqm Dayanglu Market. The market, although equivalent in size to about 45 football fields, is far smaller than the 1.12 million sqm Xinfadi.

Located in an industrial area which plays host to furniture, light fixture and alcohol wholesale centres, the usually bustling wholesale centre was noticeably empty when The Straits Times visited yesterday. Its stallholders were getting ready for the afternoon's disinfection.

City workers were headed to lunch, each carrying a white protective suit still in its plastic wrapping, goggles, shoe covers and gloves.

Tomato seller Ma Xiaoli, who was hawking produce under a tent in an open area, said health workers had swabbed her and other vegetable sellers earlier in the morning. But she had been allowed to continue running her stall while awaiting the results of her test.

"Usually this entire area will be busy for the whole day, with cars, scooters and pick-ups everywhere but look at this," the 26-year-old Hebei native said, pointing to the empty carpark. She had on a bandana, with a surgical mask over it.

Sellers were to pack up by 3pm, when the health authorities would descend on the market to conduct what has been described as "thorough cleaning and disinfection".

Butchers still in the deserted meat section past 1pm were frantically trying to clear their stocks before the disinfection.

"I don't want water to get on my things and spoil them," said a mutton seller who was wrapping the electrical components of a suspended fan in plastic.

Others were concerned about when the market, which operates round the clock, could reopen.

"I'm not even sure about coming back tomorrow," said beef seller Zhang Danni, making quick work of a rack of ribs for a waiting customer.

Most of the stalls around her had shut before noon, shortly after they had been notified of the cleaning and nucleic acid testing.

She added: "My worry is if they find a case here, then all of us are in trouble."

But the seafood area, where vendors were the first to be tested for the virus, had already been closed for cleaning. Workers in full protective gear were spraying disinfectant around empty fish tanks.

Since news broke that traces of the coronavirus had been found on one of the market's cutting boards that had been used for imported salmon, with government scientists saying on state television that the disease could have entered Beijing through imported produce, the city has gone into overdrive, pulling the fish off shelves while ordering restaurants not to sell it.

Customs officials in Beijing have stopped all salmon imports while Shanghai now requires each batch to be tested for Covid-19.

Some Beijing district councils have even gone a step further by saying restaurateurs cannot sell imported seafood, while others are barred from using locally bought seafood.

But World Health Organisation officials have put that theory on ice, saying on Monday that while the outbreak's origins are uncertain, the claim that it was caused by imports or the packaging of salmon was not the "primary hypothesis".

Japanese restaurants, which usually serve imported raw fish, have been hit extra hard by the city's new line, just as many were starting to see their business return to normal after months of coronavirus-linked sluggishness.

"Hopefully, this blows over quickly and we can resume our imports soon. It's quite difficult to run a business when so much of our items are imported," said the owner of a Japanese izakaya or pub in the Dongcheng district of Beijing who declined to be named.

"At least we have other grilled or fried items to sell."