Leftover sushi? Don’t let it languish in the fridge
Grabbing a container of ready-to-eat sushi from the grocery store? Be sure to say sayonara to any leftovers still in the refrigerator after 24 hours, a food safety expert says.
To-go sushi’s short shelf life
“Any signs of spoilage are bad, but just because it looks good doesn’t mean it’s safe,” said Keith Schneider, an associate professor of food science with University of Florida’s Institute of Food and Agricultural Sciences.
Takeout and doggie bags from sushi restaurants should be eaten when you get home or thrown away, he said.
The problem is that foods can interact when they’re placed together. Inside a sushi roll, bacteria sometimes find ideal conditions in the spaces where moist ingredients come in contact with dry ones, or where foods with different pH meet. The result: faster spoilage.
“Sushi is meant to be consumed the day you buy it,” said Schneider, who co-authored a document on safe sushi preparation in retail operations with UF seafood expert Steve Otwell. “Each food item has a different spoilage rate so it’s difficult to put a shelf life on (sushi).”
Schneider says sushi hasn’t been associated with many reports of foodborne illness, but he nonetheless advocates a better-safe-than-sorry approach.
The term “sushi” covers many foods made with vinegar-treated rice and raw or cooked items such as meat, seafood and vegetables. Probably the best-known sushi varieties are makizushi, rolls wrapped in seaweed and sometimes coated with rice; and nigirizushi, rice mounds topped with a slice of fish or other seafood.
Raw fish might seem the biggest food-safety hazard in sushi, but Schneider says that’s not the case — it’s often frozen and thawed before use, to kill parasites.
Actually, rice is more likely to cause problems, he said. A bacterium called Bacillus cereus can grow in cooked rice if it’s not prepared and handled properly. That’s one reason vinegar is essential to good sushi rice — it provides acidity that discourages the bacterium.
Schneider cautions consumers who buy ready-to-eat sushi to minimize the chance it will warm up. Take it from the cooler just before purchase, bring it home quickly and refrigerate it immediately unless you plan to eat it right away.
“It’s not one of those things you want to leave on the counter,” he said.
Packaged sushi sold in supermarkets is often made by specialty companies via franchises within the stores. The biggest such company in North America is Advanced Fresh Concepts (AFC) based in Rancho Dominguez, California, which sold Southern Tsunami brand sushi in more than a hundred supermarket chains.
Jeff Seiler, AFC’s compliance director, agrees with Schneider’s 24-hour recommendation, and suggests consumers eat ready-to-eat sushi as soon as they get home to ensure the best flavor.
“Wal-Mart opened in Plano, Texas, with a sushi bar in it,” he said. “I think people see it as sort of a clean, healthy alternative to other fast foods at the same level of convenience.”
Statistics on ready-to-eat sushi sales are sparse, but Issenberg reported in his book that one survey indicated 30 million US adults eat sushi regularly.
And though the idea of grocery shoppers picking up packaged sushi along with dog food and dish soap may rankle some aficionados, Issenberg says from a historical perspective, this trend is simply a return to sushi’s roots.
In the late 19th century, sushi was a low-cost snack sold by Tokyo street vendors, he said. Only later did this proto-fast food become glamorous and expensive. The first US sushi bar opened in Los Angeles’ Little Tokyo in 1964, an upscale establishment frequented by Japanese-American businessmen.
“In Japan, (sushi’s) origins are far closer to the experience of going to a supermarket and getting takeout and bringing it home, than actually sitting down in a sushi bar and spending $100 on your dinner and eating it there,” he said.