A U.S. senator has called for a government investigation into the national security impact of garlic imports from China.
Republican Senator Rick Scott has written to the commerce secretary, claiming Chinese garlic is unsafe, citing nonsanitary methods of producing it.
China is the world's largest exporter of fresh or packaged garlic and the US is a major consumer.
But the trade has been controversial for many years.
The US has accused China of "dumping" garlic on the market at below cost.
Since the mid-1990s, it has imposed tariffs or heavy levies on Chinese imports in order to prevent U.S. manufacturers from going bankrupt.
In 2019, during the Trump administration, those tariffs went up.
In his letter, Scott addresses these existing concerns. But he goes on to highlight "a grave public health concern over the quality and safety of garlic grown in foreign countries - most notably, garlic grown in communist China."
He refers to practices which he says are "well documented" in online videos, cooking blogs and documentaries, including growing garlic in sewage, the BBC reports.
He has called for the Commerce Department to take action under a law allowing investigations into the impact of specific imports on U.S. security.
Senator Scott also goes into many details about the various types of garlic to be seen: "All classes of garlic, whole or separated into cloves, whether or not rinsed, cooled, frozen, stored or temporarily packed in water or otherwise. neutral substance."
"Food security is an existential emergency that poses grave threats to our national security, public health, and economic prosperity."
The Office for Science and Society at McGill University in Quebec, which tries to popularize and explain scientific issues, says there is "no evidence" that wastewater is used as fertilizer for garlic growing in China.
"In any case, there is no problem with this," said a paper published by the university in 2017.
"Human remains are as effective a fertilizer as animal remains. Spreading human wastewater in fields where crops grow doesn't sound attractive, but it's safer than you might think," says the study.