(Adds Tyson Foods, Brazilian meat companies signing declarations requested by China)
By Dominique Patton and Karl Plume
BEIJING/CHICAGO, June 23 (Reuters) - China's soybean buyers are asking exporters to sign a letter guaranteeing their cargoes are not contaminated with the novel coronavirus, U.S., Brazilian and Canadian soy industry officials said on Tuesday.
China is trying to prevent any risk of new COVID-19 infections from imported goods as it takes aggressive measures to contain a recent spike in coronavirus infections linked to a sprawling wholesale food market in Beijing.
Most international authorities say there is no evidence that the coronavirus can be transmitted from food to people.
Two grain export traders told Reuters that their companies have not responded to the request and are looking to federal agriculture officials or broader industry groups for a unified response.
The U.S., Brazilian and Canadian departments of agriculture did not respond to requests for comment.
Last week, overseas suppliers of meat and fruit said China's General Administration of Customs asked them to sign declarations ensuring the safety of their shipments to China.
Brazilian meat producers JBS SA, Minerva SA and Marfrig Global Foods SA signed declarations that said their exports are free of the virus, sources at each company said.
Tyson Foods Inc, the biggest U.S. meat supplier, said it signed the certification because it is confident in the safety of its products. China's customs authority said on Sunday it suspended imports from a Tyson poultry plant hit by the coronavirus.
Rival U.S. chicken company Perdue Farms said it agreed to comply with food-safety guidelines from the World Health Organization and United Nations food agency.
The U.S. Department of Agriculture and trade representatives are telling meat exporters to make their own decisions about whether to sign the declarations, a source who has been in contact with the USDA said. The source said the USDA on Friday advised shippers against signing the letters.
For soybeans, efforts to ensure that cargoes are free from the coronavirus are coming from local customs authorities, not Beijing, said Zhang Xiaoping, China director of the U.S. Soybean Export Council.
"Seems ripe for false positives," a U.S. soybean export trader said, who asked not to be identified in order to speak candidly. "How in the world do you argue that you verified it to be coronavirus free? We have not responded to it."
Sergio Mendes, director general of Brazil's export grain association Anec, said the group is preparing its response and did not expect the Brazilian government to interfere. Contamination is virtually impossible as the ship loading process is almost entirely automated, he said.
"We would be guaranteeing the unimaginable," Mendes said.
The Canadian government views China's requests as a private sector matter and is not recommending whether exporters should provide guarantees, Soy Canada executive director Ron Davidson said.
Port workers unloading soybeans present a greater risk for contamination than the crops themselves as bulk shipments spend at least three weeks at sea, longer than the virus can survive without a host, said Iowa State University grain quality expert Charles Hurburgh, a professor of agricultural engineering.
"No one will certify to that risk, I am sure," he said.
China is the world's top soybean buyer and is expected to import about 94 million tonnes in the 2019/20 crop year, mostly from Brazil and the United States. Imported soybeans are crushed to produce soymeal to feed livestock.
Multinational traders Bunge Ltd and Louis Dreyfus Co did not immediately respond to requests for comment. Archer Daniels Midland Co and Cargill Inc declined to comment.
The Produce Marketing Association, which represents U.S. fresh-produce suppliers, said it did not know of companies that were asked to sign the declaration.
Richard Owen, an association vice president, questioned whether China was using the issue as a trade barrier after agreeing to buy more U.S. farm goods as part of an initial trade deal signed in January.
"The question is, what do they hope to achieve with this?" Owen said. "You would think they would be looking for every way they can to squeeze out every container of product, whether it be meat or fresh produce or whatever, in order to hit that goal, versus putting up any kind of barriers to prohibit trade again.”
Reporting by Dominique Patton in Beijing; Karl Plume, Tom Polansek, P.J. Huffstutter, Julie Ingwersen and Christopher Walljasper in Chicago; Ana Mano and Nayara Figueiredo in Sao Paulo; Rod Nickel in Winnipeg and Kelsey Johnson in Ottawa; Editing by Kirsten Donovan, Aurora Ellis and Cynthia Osterman