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Animal feed and the food supply, Seafood: Farmed vs. wild
Seafood: Farmed vs. wild The issue: Contaminants • What they are PCBs, dioxins, and flame retardants. • How they could get in feed Farmed-salmon feed can contain oil and meal from fish caught in polluted waters. • The danger PCBs and dioxins are likely carcinogens in humans. • The solution Industry should use feed fish from cleaner waters and find substitutes for fish oil. The FDA is responsible for ensuring the safety of imported seafood. And there’s a lot of ensuring to do: About 80 percent of seafood sold in the U.S. is imported. Yet the FDA tests only about 2 percent of those imports, mainly for drug residues. In January 2004, the GAO reported that despite an earlier recommendation, the FDA had not established agreements with other countries to document that their seafood-safety systems are as stringent as the U.S. system. Salmon are one of the major imports. They’re high in heart-healthy omega-3 fatty acids, but their fat also tends to accumulate toxins consumed in the wild or on fish farms. In the wild, a salmon’s meal of choice is smaller fish. On farms, salmon are typically fed concentrated fish meal and fish oil. Results of a study led by Ronald Hites, Ph.D., an environmental chemist at Indiana University, and published in the Oct. 1, 2004, issue of Environmental Science & Technology showed that farmed salmon tended to have higher levels of PBDEs, flame retardants used in polyurethane foam, than wild salmon. PBDEs have become ubiquitous in the environment and appear to have found their way into farmed-fish feed. They have posed neurological problems in animals; their toxicity in humans isn’t known. The Hites team also reported in the journal Science in January 2004 that compared with wild salmon, farmed salmon had more PCBs and dioxins, likely carcinogens. On its own, each contaminant was well below the FDA’s tolerance level. But some samples had combined concentrations high enough to trigger local consumption advisories. The data indicated that farmed salmon from Europe were more contaminated than those from North and South America. Two major international fish-feed producers, EWOS Ltd. of Norway and Nutreco Aquaculture of the Netherlands, test their feed for contaminants, and spokesmen say they’ve taken steps to reduce levels of PCBs and dioxins. Nutreco Aquaculture, for example, has increased the substitution of vegetable oil for fish oil, says Viggo Halseth, managing director of the company’s research center. The FDA is concerned, however, that some foreign fish and seafood producers are adding unapproved drugs to feed, leaving traces in food that could pose human health risks. Since 2003, foreign shipments of farmed salmon reportedly tainted with malachite green, a fungicide not approved for aquaculture use in the U.S., have been stopped in the United Kingdom and the Netherlands, according to press reports. This fiscal year, the FDA plans to test catfish--80 samples of domestic, 80 of imported--for malachite-green residues. Tests from fiscal years 2001-03 have found no residues. Plans to test salmon are on hold, an FDA spokeswoman says, while the agency assesses detection methods. Chloramphenicol, a potent antibiotic and suspected carcinogen, is another cause for concern. Although federal regulations prohibit its use in animal feed, chloramphenicol has been found in shrimp imported to the U.S. The Louisiana Department of Agriculture & Forestry began testing imported shrimp in 2002. Ten percent of its samples to date have been tainted with the drug. This and other incidents here and abroad led the FDA to announce increased testing of imported seafood for chloramphenicol. Currently, the agency collects just eight samples of imported shrimp each week, according to an FDA spokeswoman. “We are concerned about chloramphenicol and malachite green and other veterinary drugs that are not allowed in the United States because there are serious health concerns,” says Stephen Sundlof at the FDA. The agency is trying to work with other countries to help them resolve problems with medications unapproved in the U.S., he adds.
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