SHOUGUANG (NYTIMES) - Along the roads leading into the small eastern city of Shouguang, workers in hazmat suits stop cars and take passengers' temperatures.

The fever checks are mandatory at offices, too. Whole neighbourhoods have been barricaded off to non-residents. All the hotels are shut.

Shouguang is 800km away from the epicentre of the coronavirus outbreak. But the tight precautions reflect the city's vital importance to China: This is where the country gets its vegetables.

The virus crisis is testing China's ability to feed its 1.4 billion people, one of the Communist Party's proudest achievements.

Cooped up at home and fearful that the epidemic could last weeks or even months, families across China are hoarding provisions, making it harder for shops and supermarkets to keep fresh food in stock.

Many places have closed roads to passing traffic, slowing truck shipments and raising freight costs.

Chinese officials have vowed to keep food flowing to Wuhan, the inland city of 11 million at the centre of the outbreak.

Shouguang, one of the country's biggest hubs for growing, trading and shipping vegetables, has begun donating produce by the truckload to the locked-down city.

Officials are on alert for signs of strained supplies throughout the rest of the country. Retail prices for fresh food have crept up in many places.

BIRD FLU OUTBREAK

The Shouguang vegetable price index, a widely watched daily gauge, rocketed to a multi-year high last week.

Poultry farmers are warning that supplies of chicken feed are running low because of transport restrictions, and millions of birds could die as a result.

As if one dangerous disease was not enough for China right now, the national government over the weekend reported a "highly pathogenic" outbreak of bird flu at a chicken farm in Hunan province.

Some 4,500 chickens had died, and 17,000 were culled pre-emptively.

Grocery bills in China were already climbing in recent months as an epidemic of swine fever ravaged the nation's hog population.

Rising consumer prices played a role in the protests that culminated in the 1989 Tiananmen Square massacre, and the government has worried about inflation ever since.

Hence Beijing's herculean efforts to keep food moving as the coronavirus brings parts of China's economy to a near halt.

The Ministry of Agriculture has ordered the farm industry to increase output "by every possible means" while also keeping prices "basically stable".

The authorities have made a show of punishing stores that gouge consumers - one supermarket received a US$70,000 fine for selling cabbage at US$9 (S$12.40) a head, according to official news media.

Two state-run food giants have been ordered to ramp up supplies of rice, flour, cooking oil and meat to Wuhan and Hubei province, where the city is situated.

The city of Tianjin announced recently that Kang Shi Fu, a giant maker of instant noodles, had increased production to four million noodle packets a day.

In a news conference on Monday (Feb 3), national officials said they had coordinated with six provinces near Hubei to amass a reserve of 60,000 tonnes of vegetables.

They also said they had readied 10,000 tonnes of frozen pork near Shanghai's port that could be sent to Wuhan anytime.

VAST GREENHOUSES

Still, China's ability to continue feeding itself during the coronavirus will depend in large part on how well it controls the spread of the virus itself. It will also take more than a little good luck.

Mr Wang Zhigang, a manager at one of Shouguang's main wholesale produce markets, said that as long as the virus was kept away and the city could keep shipments moving, China's vegetable supplies should remain ample.

"If Shouguang is locked down, then there's nothing we can do," Mr Wang said through his protective face mask.

At first glance, Shouguang, a nondescript city of 1.1 million people, does not look like an indispensable node in China's economy.

But the vast greenhouses that line the streets here produce 4.5 million tonnes of vegetables a year.

A far greater amount moves through the city's wholesale markets annually en route to every corner of China.

The produce trade has created such immense wealth in Shouguang that Farmers' Daily, a state-run newspaper, last year hailed the city as the "Silicon Valley of the vegetable industry".

Recently, as virus concerns drove up demand for vegetables across the country, farmers in Shouguang have been tapping their reserves, according to Mr Wang, the wholesale market manager. Some growers here keep months' worth of potatoes, radishes, onions, cabbages and other vegetables that can weather cold storage.

At the front gate of the wholesale market, workers check the temperatures of the truck drivers who bring produce in and out.

All vehicles are sprayed with disinfectant. Outsiders are forbidden.

Shandong, the coastal province where Shouguang is situated, has so far reported 275 cases of the new virus, fewer than some less-populated provinces.

Last week, 350 tonnes of Shouguang produce travelled to Wuhan on a convoy of trucks led by a police car.

The trucks were full thanks to people like Mr Li Youhua, 51, who grows chilli peppers in a village near the city.

Late one night last week, the village committee put out a call on messaging app WeChat, asking local farmers for extra produce that they could send to Wuhan.

Mr Li swung into action. He, his wife and their two daughters grabbed flashlights and worked through the night.

They harvested half a tonne of chillies, twice their normal daily output.

Mr Li said he had not yet heard from the authorities about when or what he might be paid for his contribution.

If it ends up being a gift, that would be all right by him, he said.

CARAVAN OF TRUCKS

When Shouguang suffered catastrophic flooding in recent years, people from across China came to his and other farmers' aid. "We cannot forget that," Mr Li said.

On Saturday, a second caravan of trucks from Shouguang set out for Wuhan bearing broccoli, cauliflower, potatoes and more.

As the trucks' drivers waited to leave the city that morning, they pondered what they had got themselves into.

They were not sure how much they would be paid for the job.

But they knew that when it was finished, they would be quarantined at home for two weeks, meaning potentially thousands of dollars in forgone income.

Still, Mr Ma Chenglong, 34, volunteered right away when the call went out on WeChat. "When the country is in trouble, we common people have a duty," Mr Ma said.

He was using lengths of wire to reinforce a red banner that had been hung on the side of his truck.

The banner read: "Rushing to Wuhan's rescue with 5,000 tonnes of vegetables."

The drivers' pride was mixed with trepidation.

One driver gave only his surname, Song, because he was afraid his family would be stigmatised if people heard he was travelling to Wuhan. The only person he had told about his journey was his wife.

He, too, had signed up fully aware of the health and financial risks. "We have to listen to the government," Mr Song said. "Whatever the government wants, that's how it's going to be."