Tuna is arguably the most popular offering at sushi bars. Many customers like slices of blood-red fish slathered in a spicy wasabi sauce. Others prefer the more simple nigiri style, which is sliced tuna over rice.
But now a public health advocacy group is warning about the safety of tuna sushi and questioning the Food and Drug Administration's system of monitoring the mercury levels in fish, based on tests on a small sample of such delicacies at Los Angeles restaurants.
The group, GotMercury.org, purchased sushi from five top Zagat-rated restaurants in Southern California and from the Benihana Inc. chain in late January. Instead of eating the orders, the Forrest Knolls, Calif.-based organization took the fish for testing at CRG Marine Laboratories in Torrance.
The mercury levels of the 12 tuna samples averaged about double the FDA standard, and a quarter of the orders were near or above the limit where the agency says fish should not be sold, said Eli Saddler, a public health analyst and attorney for GotMercury.org.
"Eating sushi has become the new Russian roulette," Saddler said.
The advocacy group focused on sushi because the popular food has become one of the largest sources of fresh tuna consumption. Saddler believes this is the first time an independent group has attempted to monitor mercury levels in sushi.
The samples came from some of Southern California's toniest restaurants -- Matsuhisa, Sushi Katsu-ya, Sushi Sasabune, HamaSaku and Sushi Nozawa. GotMercury.org also went to Benihana in Santa Monica because it's part of a large national chain where sushi is featured.
"Our testing shows a pattern of mercury levels being significantly higher than what the FDA reports," Saddler said.
Mercury, which is linked to reduced brain development in fetuses and young children, is found in at least trace levels in nearly all fish.
The FDA and Environmental Protection Agency have warned that women who may become pregnant and young children shouldn't eat certain high-mercury fish, including swordfish, shark, tilefish and king mackerel. They should also limit their consumption of tuna, the agencies have said.
Increasing concern about mercury in fish has pushed some in the food industry to advocate improved testing.
Last week, Micro Analytical Systems Inc. of San Rafael, Calif., and Clackamas, Ore.-based wholesaler Pacific Seafood Group began a test venture to provide fish certified to be low in mercury to Holiday Quality Foods, a small grocery chain in rural Northern California.
The venture uses a rapid-testing device developed by Micro Analytical that takes minutes rather than days to determine how much mercury is in a fish sample. In most instances, only fish that tests below the median mercury level in the FDA database -- for yellowfin tuna, that's 0.27 part per million -- gets the venture's Safe Harbor label, indicating that it is a low-mercury filet.
Aliso Viejo hairdresser Christopher Bliss used to eat sushi as often as twice weekly. But when his wife Valerie became pregnant two years ago, they gave it up because they were worried about the mercury content of the fish.
"Now we eat it once a month. I don't think that's enough to worry about," Bliss said. Still, they have enough concern not to feed it to Ava, their 18-month-old daughter.
Susan Pasarow of Studio City likes to eat at Sushi Katsu-ya, not far from her home.
"They are the best," Pasarow said. "I like to order all the yummy rolls." And she gets lots of items with tuna.
Pasarow wasn't happy to learn that Katsu-ya fish had the highest mercury concentrations among the 12 samples, but said she was aware of the problems of mercury in fish.
"That's why I hesitate to have sushi very often. I go maybe once a month or once every other month," Pasarow said.
The two samples from Sushi Katsu-ya in Studio City came back with mercury concentrations of 1 part per million and higher, above the FDA's threshold for mercury in any seafood species, Saddler said. One sample from Sushi Nozawa, also in Studio City, came back just shy of the limit, Saddler said.
Neither restaurant responded to calls asking about the tests. Representatives of Benihana and Matsuhisa in Beverly Hills declined to comment on the findings. And HamaSaku in Los Angeles had Young Kim of Ocean Group Inc., its tuna provider, return the call.
"We are just a wholesaler, we don't monitor for mercury," Kim said.
Saddler said he didn't blame the restaurants for the problem.
"I know this is the way the fish comes in, but they should do a better job of warning customers," Saddler said.
That's the practice of Nobi Kusuhara, chef and owner of Sushi Sasabune in West Los Angeles. He said it's well known that tuna and swordfish have high mercury levels and he regularly warns pregnant customers not to order those fish.
"We would like to be able to get fish that has been tested for mercury," Kusuhara said. "That would be good for the customer and would be good for us."