A new Consumer Reports (CR) study released Friday found that 60 percent of 342 samples of frozen shrimp it tested contained Salmonella, Vibrio, Listeria, or E. coli, and 2 percent tested positive for the superbug MRSA (Methicillin-resistant Staphylococcus aureus).
For its new report, “How Safe is Your Shrimp?,” CR researchers bought 284 raw and 58 cooked shrimp samples for testing last March in 27 cities across the country from retailers such as Walmart, Kroger, Albertsons, Costco, Fry’s Marketplace, Hy-Vee and Sprouts Farmers Market. CR didn’t test fresh, never-frozen shrimp since U.S. consumers don’t buy much of that.
Results from testing for bacterial and drug residues showed that 16 percent of cooked, ready-to-eat shrimp contained several bacteria, including Vibrio and E. coli. Antibiotics were found in 11 samples of raw, imported, farmed shrimp, and MRSA was detected in 7 raw shrimp samples.
Nearly all (94 percent) of the raw shrimp available in the U.S. are farmed in Asian countries, including Thailand, Vietnam, India and Indonesia. Because of the crowded and polluted conditions that typically exist in fish-farming ponds or tanks, the shrimp are often given antibiotics such as tetracyclines, which is illegal in shrimp imported to the U.S.
Specifically, the CR report noted that “of 205 raw farmed imported shrimp samples, 11 samples from Vietnam, Thailand, and Bangladesh tested positive for one or more antibiotics: Nine tested positive for oxytetracycline, three contained enrofloxacin, and two contained sulfa antibiotics.”
Bacterial contamination on shrimp poses a problem because, even though cooking the shrimp should kill any bacteria, the report findings indicate that more needs to be done to prevent such contamination in the first place.
“Like with any raw meat, bacteria has a good chance of being cooked off,” Urvashi Rangan, Ph.D., executive director of CR’s Consumer Safety and Sustainability Group, told Food Safety News.
Freezing may also be a good step in controlling Vibrio, she noted, adding, “but 28 percent of our frozen samples had Vibrio.”
“Vibrio illnesses are on the rise, according to [the U.S. Centers for Disease Control and Prevention], so Vibrio control is one of the things our federal agencies are concerned about,” Rangan said.
Antibiotic residues in shrimp are a concern because they’re illegal under U.S. food safety laws and because they indicate differing food safety standards between the U.S. and exporting countries, she noted.
“It underscores that this commodity is being trucked around all over the world and standards may not be good,” she said. “It is relying on other countries to have split enforcement — one standard for our country and one for their country — which allows for shrimp coming into our country to not meet regulations.”
Rangan called finding MRSA on some shrimp samples “particularly problematic” because its presence indicates handling issues, plus the incidence levels found with shrimp were higher than previous CR testing done on chicken, turkey or pork.
“The staph can be cooked off, but when staph produces a toxin, you can’t cook it off,” she said. “There should be zero tolerance in the case of staph.”
CR sent a copy of the new report to the U.S. Food and Drug Administration (FDA) and is asking that the agency consider stepping up both the frequency of its inspections of imported shrimp at ports and fish farms and its overall regulation of the product.
Rangan said she would particularly like to see the agency include Vibrio in its HACCP regulations in performance standards and significantly ramp up the 0.7 percent of all imported shrimp which FDA reportedly tested last year.
“They can’t find what they don’t look for,” she said. “We think they aren’t looking hard enough.”
Besides its recommendations regarding increased government inspection and regulation of imported shrimp, the CR report also makes recommendations to the general public for safer handling and consumption of raw shrimp. When buying farmed shrimp (whether imported or domestic), CR suggests product certified as raised without chemicals, including antibiotics.
Specifically, the report recommends looking for farmed shrimp labeled Naturland, Aquaculture Stewardship Council, or Whole Foods Market Responsibly Farmed. It notes that there is another common certification, Best Aquaculture Practices, but testing for the study found antibiotics on four samples carrying that label.
Rangan noted that labeling of shrimp or other seafood as “natural” or “organic” should not be relied upon since there are no standards or regulations behind the terms and consequently they really don’t mean anything.
For safer handling of raw shrimp at home, she recommends that consumers keep the shrimp clean and cool (below 40 degrees F) and avoid cross-contamination.
“It can take a while to prepare shrimp, so keep it on ice. And when you’re deveining, make sure you keep it clean and cold, just as if you were preparing raw chicken or raw beef,” Rangan advised.
CR recommends buying wild-caught shrimp that has been sustainably fished whenever possible because, even though it may be more expensive, it is likely to have less bacteria, fewer residues, and less overall negative impact on the environment. The report notes that “of all the shrimp tested, wild shrimp were among the least likely to harbor any kind of bacteria or contain chemicals.”
This view was echoed by the American Shrimp Processor’s Association (ASPA) of Biloxi, MS, which released a statement Friday supporting the findings in the CR report.
“Reports like this validate our long-standing position that by asking for wild-caught shrimp and reading labels carefully, consumers and buyers can make sure they are getting quality shrimp that are free from antibiotics and disease,” said Jonathan McLendon, ASPA vice president and president of Wild American Shrimp Inc.
However, the National Fisheries Institute of McLean, VA, a trade association representing seafood suppliers and producers, indicated that sections of the report raised questions about whether CR was “simply looking for problems they couldn’t substantiate but reported on them anyway.”
“The fact is shrimp, imported, domestic, farmed or wild, is a healthy part of a balanced diet despite the hand wringing and hyperbole we see in this report,” NFI said.
Some information about shrimp included the CR report:
- Americans eat, on average, nearly 4 pounds of shrimp per person each year, and the amount is increasing.
- Nearly 94 percent of the U.S. shrimp supply is imported.
- FDA examined 3.7 percent of foreign shrimp shipments in 2014 and tested 0.7 percent.
- Raw, farmed shrimp from Bangladesh and India were the most likely to carry bacteria, with 83 and 74 percent tainted, respectively.
- Raw, wild-caught shrimp from Argentina and the U.S. were the least likely to be tainted, at 33 and 20 percent, respectively.
The “How Safe is Your Shrimp?” study will be published in the June 2015 issue of CR.
