Once dubbed one of the world's most disgusting foods, China's preserved eggs are now flying off the shelves at Costco stores across the United States.

Known to some Westerners as "century eggs" or "thousand-year-old eggs" for their dark, translucent appearance and bold flavor, these traditional Chinese delicacies have long sparked mixed reactions abroad.

CNN in 2011 published an article that claimed to reveal the world's most disgusting foods. Top of the list? China's century eggs.

But now, they're enjoying a surprise moment in the American mainstream.

At Costco, the eggs are sold in sleek gift boxes of 20, priced between US$13.99 and US$14.99. Some stores sold out within days.

"We planned enough stock for three months – some stores ran out in under three days," Wu Hongliang, sales manager at XURI Egg Products, the Chinese company behind the product, told tech media webiste 36Kr.

While preserved eggs have quietly sat on the shelves of Asian supermarkets for years, this marks their first widespread success in a major US retail chain.

The buzz began on Xiaohongshu, where Chinese shoppers in the US posted photos of the eggs on display. The posts quickly drew a flood of comments asking for store locations and ZIP codes.

Then came a viral boost. US food influencer "The Sushi Guy" reviewed the eggs on TikTok and YouTube, drawing more than 650,000 views. Food site Tasting Table followed up with a feature exploring the eggs' cultural roots and distinctive taste.

On TikTok, adventurous eaters filmed their reactions: some recoiled at the first bite, then returned for more. One home cook tossed the eggs into a salad, chewing thoughtfully before declaring, "I don't know what I'm doing, but it's weirdly addictive."

And it's not just overseas Chinese snapping them up anymore.

"Foreigners tend to follow the crowd," Wu said. "When they see Chinese customers loading up, they get curious and grab a pack too."

But getting into the US market wasn't easy.

XURI's first proposal to Costco was turned down. The company had to go back and make big changes – getting food safety certifications, proving their eggs were antibiotic-free and met animal welfare standards. They even became the first duck egg producer in the world to pass the strict SQF certification, which finally opened the door to a deal.

For Chinese food companies trying to go global, selling a product isn't enough anymore. They need to meet higher safety standards, build trust, and find ways to win over new customers.

Preserved eggs used to be something many Westerners wouldn't touch. Now they're showing up in shopping carts across America.

So what's next – will more Chinese flavors follow?