TOKYO, July 26 (Reuters) - In Japan, not all eels are created equal.

Especially not this year, when eel aficionados -- who devour broiled eels in a bid to beat the heat -- are opting for pricey domestic eels over cheap Chinese imports amid food safety fears.

"I'll be eating domestic eel. If it isn't domestic, I really worry," said Ruri Takeda, a 26-year-old sales worker.

Reports about tainted Chinese foods have sparked concern in Japan, especially after the United States said it would not allow Chinese farm-raised seafood imports unless suppliers proved the shipments held no harmful residues.

With some 60 percent of Japan's annual eel consumption imported from China, retailers are now scrambling to reassure nervous consumers as Eel Day -- when many Japanese feast on eel to bolster their stamina -- approaches on July 30.

"There's definitely a difference in food safety with China, and that concerns me," said Minoru Suzuki, 26, a manager at an office products firm.

Only a handful of Chinese eel products have actually violated Japanese safety standards, an Agriculture Ministry official said, with import numbers and prices holding steady.

"But given all the negative reports, many people are likely to avoid Chinese eel nonetheless," said Takeshi Sagesaka, deputy director of the ministry's Industries Marketing Division.

Eating vitamin-rich eel in summer has long been seen here as a way to gain stamina after days of heat-enervated appetites.

In 2005, Japanese ate 97,000 tonnes of eel, about 60 percent of which was imported from China already grilled.

EEL DAYS

Much of that is consumed on Eel Day -- formally known as "Doyo Ushi no Hi," a date determined by the ancient solar calendar and believed to be the hottest of the year.

Long lines form outside eel restaurants, with retailers from convenience stores and supermarkets to high-end department stores eagerly joining in, offering eel dishes to suit every budget.

Most popular is broiled eel on rice with a tangy sauce.

This year, those peddling cheaper Chinese offerings are finding themselves under pressure.

Supermarket chain Daiei Inc. has posted signs in its stores emphasizing the quality of its Chinese eel, which comes from hand-picked eel farms that are strictly tested for safety.

Others have taken similar steps.

"We have our own suppliers and send experts over to give them guidance on eel raising, so we have confidence in our product safety," said Mayumi Ito, a spokeswoman at Seven & I Holdings Co, which runs the Seven-Eleven convenience store chain.

"But as a trend, the pre-orders for our eel boxed meals are running more towards domestic."

That's despite a hefty price difference.

A Seven-Eleven serving of broiled eel on rice costs 795 yen ($6.60) for Chinese eel compared with 1,380 yen for the domestic variety.

Department store operator Takashimaya Co. sells only domestic eel and always has, a spokesman said. A one-person serving ranges from 1,500 yen to 3,000 yen.

"We aren't worried at all," he added.

Many customers appear unfazed by higher prices. "It's a question of safety, so paying more doesn't bother me," said Toshihiro Taniguchi, a 45-year-old supermarket executive.

"Chinese eel just isn't selling this year, not in our store either."