Almost a year ago, COVID-19 cases that were first reported from Central China’s Wuhan brought the entire country together to beat the deadly virus, underscoring the country's unparalleled resilience as the world still continues to struggle to rein in the pandemic. However, even for a country that claimed a strategic victory in the battle, the risk of a virus resurgence remains real and in different forms. With new cases linked to imported cold-chain foods and cargoes reported in many major hubs across the country, the spotlight is focused on how to prevent the new risk from cold-chain food imports and virus-carrying cargoes, particularly with cold winter temperatures, while ensuring the country's massive trade is not disrupted. To investigate that risk and China's response, Global Times reporters visited logistics centers, warehouses, ports and wholesale and retail markets in cities including Tianjin, Wuhan, Shanghai and Beijing, and talked with local officials on how to deal with the challenges posed by both imported cold-chain products and international freight and why China's efforts to minimize the risks of infection from cold-chain and cargo transportation are necessary.

After employees from international delivery firms UPS and FedEx tested positive for COVID-19 at Shanghai Pudong International Airport, one of the busiest airports in the world, cargo operations are continuing as normal, but freight operators and staff members have stepped up preventive measures, especially as two confirmed patients were both exposed to a contaminated container from North America. The latest outbreak in Shanghai flashed a warning sign for the country that has successfully reined in the epidemic over the past year, but which remains vigilant over new risks of the virus resurging from overseas via cold-chain and other cargoes. But in stark contrast to the massive mobilization and response when cases emerged almost a year ago, the country has been clearly steadfast and calm in face of the new risks - a show of confidence from the hard-fought victory so far.

While all employees on the ground at the Pudong airport were geared up with white and blue protective suits, those who need to enter the area must provide a negative nucleic acid test result and follow strict entry protocols.

The latest sporadic outbreak at the airport occurred when China's top health authority found that the number of cases involving COVID-19-positive imported cold-chain foods has increased significantly, affecting more areas and products, such as seafood, meat and poultry. The infections have also extended from cold-chain food to containers.

A few kilometers away from a pier in Binhai New Area, a sub-provincial district that combines ports, industrial and free trade zones in North China's Tianjin Municipality, a constant flow of trucks carrying containers in various colors are seen, showcasing the vitality of Chinese foreign trade. However, it has given the country that gained a hard-won victory over COVID-19 a severe test as winter sets in.

According to Tianjin health officials, two confirmed cases earlier this month caught the coronavirus from pig heads arriving from North America. The two infected workers are both related to the cold storehouse of Tianjin Hailian Frozen Food Co, located in Binhai New Area.

While Hailian's cold storehouse has been closed, Global Times reporters found several frozen product containers were piled up at the outdoor base of Tedahang Cold Chain Logistics, one of the major cold chain companies in Tianjin.

Different from ordinary containers, there is a motor, a fan and small digital screen on the outside of the cold chain container, which helps maintain constant temperature. A food seller who has provided hot meals for truck drivers along the road outside Tedahang for years told the Global Times that the cold chain containers have been placed there for several days without any movement.

At a customs inspection zone a few kilometers from the cold-chain logistics site, Global Times reporters learned from some employees who frequently came in and out of the zone that since the latest outbreak in Tianjin, no one other than customs employees and staff on the ground have been allowed in, while some staff in protective suits were in the zone.

Since Chinese customs reported coronavirus found on packaging of imported frozen shrimp from Ecuador in July, about 16 provincial-level regions have reported at least 41 cold-chain related coronavirus cases, according to open statistics. Especially in November, the number of cases grew to 24, a significant surge from previous months. The most frequently reported cases were related to South American countries including Ecuador and Argentina.

A worker in charge of inspecting and disinfecting imported cold-chain products in Baishazhou, the biggest farm produce market in Wuhan, Central China's Hubei Province, told the Global Times that the market has enhanced inspections of such products after the reporting of cold-chain related COVID-19 cases.

"We require those who distribute those products to provide documents, including nucleic acid test results, before the products arrive. And we also conduct nucleic acid tests on every product, and disinfect them," said the workers, noting that the frozen products mainly come from countries such as New Zealand and Brazil.

Still, the city, which first reported COVID-19 cases in the country in December 2019, found coronavirus on two packages of beef imported from Brazil and on one package of fish imported from Vietnam, local authority said during the weekend. The virus was tested through routine sample tests as part of full scrutiny of cold-chain imports, a policy implemented since the outbreak in Beijing's Xinfadi wholesale market in the early summer.

After thorough study of nucleic acid sequencing and viral genome sequencing of COVID-19 patients with environmental and food samples from Xinfadi market, which was linked to an outbreak in June, Chinese scientists concluded in October that coronavirus from imported cold-chain food "is very likely to have been the cause of the Beijing outbreak, and cold-chain transportation has become a new route for viral transmission."

As part of the overall enhanced measures in the capital city, another major seafood wholesale market, the Jingshen Seafood Market, located about eight kilometers from Xinfadi, stopped granting access to individual customers after it was reopened in mid-September.

Roller warehouse shutter doors at the seafood storage section were all closed when Global Times reporters visited Jingshen market lately, and only cargo trucks were allowed in after truck drivers scanned their health QR codes. Some restaurants around the nearby Dayang Road Seafood Wholesale Market, were sealed off, and all cargo freight and business representatives from outside Beijing must take a nucleic acid test before entering the market.

Major anti-epidemic measures adopted by the market included separating the wet from the dry sections, disinfectant placed at entrances and exits, mandatory mask-wearing and all business and staff must report their health status and temperature a day before they enter the market on an app called "Jingshen E-home," the Global Times learned from some staff members of the market. Such detailed and cautious guidelines indicate the priority accorded to fending off potential risks brought by cold-chain transportation and frozen imports.

While authorities in more provinces and regions have been on alert to any risk from imported products, the country's top epidemiologists and infectious experts found out that the coronavirus can survive longer in dark and cold environments. For example, the clustered outbreak in Kashi prefecture, Northwest China's Xinjiang Uygur Autonomous Region, in late October, was linked to containers from Tajikistan, two experts who have taken part in Xinjiang's anti-epidemic work, told the Global Times in recent interviews.

The clustered epidemic in Kashi started with a loader who worked on a container. The infected loader transmitted the virus to his relatives who worked at a clothing factory in Kashi, Wu Zunyou, chief epidemiologist of the Chinese Center for Disease Control and Prevention, was quoted as saying in a transcript obtained by the Global Times recently.

With the arrival of winter, all international freight by air, land and sea resembles cold-chain logistics, which means they could become carriers of COVID-19, Wu told the Global Times in an exclusive interview last week.

This adds to the increasingly dire pandemic situation around the world, so the risk of infection through contaminated packages from overseas has increased significantly, Wu said, noting that daily new cases around the world have surpassed 600,000 this month.

Following such estimation, the National Health Commission (NHC) and the Ministry of Transport successively released a slew of new measures, calling for improvement in the full-fledged tracking system covering the whole process of importing frozen products and rapid response mechanism to deal with potential risks, as well as the establishment of a national-level monitoring platform to facilitate data sharing on the matter among different regions.

The infections have also spread from cold-chain food to containers, Mi Feng, spokesperson of the NHC, told at a press conference on Wednesday. However, no COVID-19 infections caused by the direct consumption of contaminated cold-chain food have been found, Zhang Liubo, a research fellow at the Chinese Center for Disease Control and Prevention (CDC), said at the press conference.

The cases linked to cold-chain and international freight have been found much more frequently also because of regular detection and sample tests. However, the positive rate still remains at a very low level, with the positive rate of nationwide sampling and monitoring of imported frozen food standing at 0.48 per 10,000, which was mainly found on the outer packaging of food, according to official data.

Massive screening, tightened inspection and strict testing rules have lengthened the procedures for traders, and staff at customs, logistics and warehouses need to work longer hours than usual amid growing concerns over international freight. Compared to the "red-zone" of hospitals where doctors and patients fully geared up to fight COVID-19 at the early stage of the outbreak, cargo ports, warehouses, and storage facilities have become the new "red-zone" where on-site staff, anti-epidemic workers and customs officials have been working day and night.

In one such "red zone" of a factory in Wuhan, a red banner saying "Strengthen red line mentality, promote safe production" is draped across the front of its cold storage building. The factory has previously tested positive for coronavirus in its cold food storage warehouse on imported beef from Brazil.

The factory has now separated platforms for uploading imported and domestic goods, in line with Wuhan's current "red zone" management rules. Its cold food storage was tightly cordoned off when reporters visited on Thursday, while dozens of inspectors dressed in full protective suits were seen unloading cold-chain products inside the barriers.

Ever since the beef from Brazil tested positive for coronavirus, the factory has been disinfecting cold-chain products, and the number of items subject to sample testing has soared.

"Those inspectors work at least 10 hours per day," said an employee at the storage, noting that they will disinfect the packaging of every box and take out all their products to examine them.

While the local government shoulders the costs for examination, the factory pays for forklifts and dockers and also has to bear the losses from the underutilization of cold-chain storage, according to the employee. It costs the factory up to 80,000 yuan per day, he said.

While the costs are going up, the enhanced anti-epidemic measures and expanded scope of scrutiny have also increased the overall workload of customs and epidemic prevention and control officers across the country.

You Jin, manager of customs declaration at Tianjin Yongcheng Shijia International Forwarders Co, told the Global Times that given the potential risks during this special period, traders and business representatives are now not allowed to enter the customs clearance sites.

"It means customs' workload has increased a lot, let alone the surging disinfection work," You said, noting that as part of the customs declaration procedures, it is usually the business representatives' job to assist customs officials to check the imports at customs inspection sites.

Testing, testing, and more testing! It has become one of China's major lessons learned from the hard-fought battle against the coronavirus. However, some Western media and public opinion are stirring controversy about the testing of packaging, including questioning whether the enhanced measures on cold-chain and imports amount to "an unfair trade barrier."

While Chinese food markets are holding their nerves in scrutinizing every piece of imported product to reduce risks, a growing number of Chinese consumers are cautiously avoiding purchasing imported foods, with some giving preference to domestic-made food instead.

In a Hema Fresh supermarket in Wuhan, Global Times reporters recently saw a small container of imported fresh food surrounded by a blue isolation strip. Disinfectant solution and gloves were placed on a small table nearby for customers. Every few meters on the container, there was a label showing that the goods had been "monitored and guaranteed", nucleic acid tested and processed under the SSOP hygiene standard.

There are also large discounts on imported cold-chain food while local customers have become much more reluctant to take any risks after going through the most unforgettable days of city lockdown early this year as Wuhan was the hardest-hit city in China.

Even though the city has emerged from the outbreak and embraced a fresh start after the outbreak was brought under control in April, many local residents hold a cautious attitude in their daily lives, especially after news of imported products triggering sporadic outbreaks in some of other cities.

One anonymous health official in Wuhan told the Global Times in a recent interview that they had received several phone calls from local residents in Wuhan asking what to do with the imported frozen meat in their refrigerators that they were afraid to open, and asked if the government could take them away.

Given the decreasing demand, merchants and traders have also been adjusting their business plans by reducing the imports, and some "don't dare to take any risks."

"People in Wuhan who lived through those difficult days know that our current life is hard won. The country has invested so much and the local residents have paid a big price," the owner of a wholesale business that sells frozen beef and mutton at the Baishazhou market in Wuhan, told the Global Times.

He said he has not imported any more products since Wuhan's lockdown on January 23 and that he still has some stock that was imported from New Zealand and Australia before the outbreak.

"We don't dare to take risks by importing cold-chain products for the sake of short-term benefits," said the owner surnamed Zhang.

While many see the heightened measures by Chinese civil aviation authorities, ports and freight transportation operators for imported shipments to minimize the risk of infection as "normal and necessary," some of the frozen product importers and forwarders admitted that they felt the pinch of the pandemic.

In the Tianjin International Trade and Shipping Service Center in Binhai, where many people were handling import or export application papers for local customs, Zhang, a customs declaration specialist, had just finished his work.

"We do have higher costs now because they are cold-chain containers, which need freezing and other conditions. Each cold-chain container costs around 1,000 yuan ($152.3) to 2,000 yuan per day, we have more than 100 containers on hold, which means we lose more than 100,000 yuan per day, which is a big number for us," Zhang said.

And some clients have required transfer of their products in Shanghai port or Qingdao port, where the process can save a bit of time, the industry insider noted.

"Despite the additional time and effort, I understand it is quite necessary at the moment," Zhang said."

The coronavirus has been ferociously "beating our door, threatening us and is at the edge of breaking in," Wu, the top CDC expert, told the Global Times when referring to the transmission of virus through international freight and cold-chain imports.

This winter, the world faces a highly challenging test, Wu said, noting that China has accumulated experiences over the past 11 months including early monitoring and minimizing the risks, and taking effective measures.

"We are confident in passing this test, and will never let the epidemic happen again," he said.