Is Shrimp Good for You? Antibiotic Resistance

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About 90% of shrimp consumed in the United States is imported, and because much imported seafood is farm-raised in confined conditions, drugs are used to prevent or treat disease and increase survival rates, and residues of some of these drugs can cause cancer or allergic reactions, or contribute to antibiotic resistance.

Among different kinds of seafood, shrimp have had the highest frequency of veterinary drug violations, primarily for nitrofurans and chloramphenicol. The United States banned chloramphenicol 35 years ago due to a link with a rare and often fatal disease called aplastic anemia. Nitrofurans are also dangerous because of their potential cancer-causing properties. So, their use in animals produced for human consumption is similarly banned in Europe and the United States.

For something as potentially dangerous as chloramphenicol, governments around the world have established zero-tolerance policies, which means that no residues in food are permissible. However, traces of chloramphenicol have been detected in shrimp. Unlike most of the animals we eat, who have multiple organs for drug excretion, shrimp possess only one, which may allow more antibiotics to build up in them. But you don’t know, until you put it to the test.

There have been four studies published on the presence of banned drugs in retail U.S. shrimp. One found that 92% of imported, farm-raised shrimp tested positive for at least one drug that is banned for use in the United States. Another, of just six shrimp from stores in Arizona and California, found drugs in two of them. The third tested dozens purchased in Louisiana from many of our main shrimp importers, and 70% tested positive for the zero-tolerance carcinogenic nitrofurantoin. Of all the countries, Vietnam appeared to be sending us shrimp with the most types of antibiotic residues. The 100% positives in Bangladesh and Ecuador were based on just a single positive sample—one out of one—for both countries. The fourth, however, found no antibiotic residues. Unfortunately, only a small fraction of imports are tested by the U.S. Food and Drug Administration, and therefore the potential for shipments with antibiotic-tainted shrimp to slip through the cracks remains.

And they’re mostly from Asia, which has been identified as posing a very significant risk to the global burden of antibiotic resistance. Stocking densities on shrimp farms are often very high, which concentrates bacteria and raises stress levels in the animals, which increases their susceptibility to infection, leading to outbreaks that kill like a billion shrimp at a time. Shrimp don’t respond to vaccination; so, to combat disease, farmers employ a range of chemicals––the residues of which can end up in the final product we may eat.

Even in more traditional systems, where human and animal waste is dumped into shrimp ponds, the antibiotics that end up in the manure end up just increasing overall antibiotic exposure. Aside from the potential for fostering antibiotic resistance, consuming antibiotic residues can have a direct toxic effect, and the constant traces of antibiotics can also disrupt the human microbiome, as has been demonstrated. The consumption of shrimp containing potentially unsafe levels of antibiotics from aquaculture, shrimp farming, is a global concern due to overuse of antibiotics. There is clearly an urgent need for governments to regulate the use of antibiotics in crustacean production.

In 2001, chloramphenicol was detected in shrimp imported into Europe from Asia, triggering a food scandal, and the regulatory response spilled over to other major seafood-importing countries, including the United States. The U.S. Food and Drug Administration started testing, and every year has rejected shrimp due to the presence of antimicrobial drugs––the most contaminated of all tested seafood products. That shows the system is working, right? Well, only a small amount of imported seafood is actually inspected. How small? For shrimp, about four samples out of every 10 million pounds (4,535 tons) of shrimp are tested. So, assuming there are about 25 shrimp in a pound (0.45 kg), that’s like one sample tested for every 60 million shrimp. Of course, they come in big batches, yet the FDA only tests about 0.1% of the million annual shipments that come in every year. Based on this level of testing, seafood shipments from a foreign processing facility would have a roughly one in a thousand chance of being selected by the FDA for drug residue testing. Is that because positive findings are so rare? No, about every one in every 10 shipments of shrimp turns up contaminated with unsafe drug residues. So, that means like a hundred shipments of the other 999 that weren’t tested may also be contaminated; yet, they can go straight to restaurants or grocery stores.

And we only test for a few drugs. Europe, Japan, and Canada are picking up seven to 10 different drugs, whereas we only look for two. So, we are likely missing the wider range of drugs picked up by other countries.

Why doesn’t the FDA test more? According to FDA officials, they don’t have the resources to test more. Okay, said the GAO (Government Accounting Office), which is the congressional watchdog, how about forcing the countries that are sending the shrimp to test for drugs before they ship them here? Let them pay for it. That’s what Europe does. Well, the FDA decided not to pursue such agreements with other countries to require them to test seafood exported to the United States for unsafe drug residues, as Europe does. Why not?

They didn’t think some of the countries that send us shrimp might be able to, because they lack the laboratory infrastructure and capabilities needed to test for the drugs of concern to the FDA. I’m reminded of an outbreak investigation of salmonella linked to shrimp, where the investigators had to explain to the exporters that they probably shouldn’t be scooping up shrimp off the floor.

But wait, countries exporting to Europe are able to comply; so, what ends up happening is that the United States may still be a market for at least some seafood that did not meet the safety standards of Europe. As a result, shrimp that cannot be shipped to European countries because of concerns about violative drug residues may be shipped to the United States; no problem. It’s like the use of some coloring agents used to disguise shrimp diseases: approved in the United States, but prohibited elsewhere due to concerns around causing ADHD symptoms in children. Countries know they can always send products here, and even if they do use drugs they aren’t supposed to, there’s only a one in a thousand chance we’ll even check.

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• Shrimp disease in Asia resulting in high U.S. import prices. Bls.gov. Jun 30, 2014.
• Imported Seafood Safety: FDA and USDA Could Strengthen Efforts to Prevent Unsafe Drug Residues. Gao.gov. Sep 15, 2017.
• Love DC, Rodman S, Neff RA, Nachman KE. Veterinary drug residues in seafood inspected by the European Union, United States, Canada, and Japan from 2000 to 2009. Environ Sci Technol. 2011;45(17):7232-7240.
• Chinabut S, Somsiri T, Limsuwan C, Lewis S. Problems associated with shellfish farming. Rev Sci Tech. 2006;25(2):627-635.
• Tu HT, Silvestre F, Phuong NT, Kestemont P. Effects of pesticides and antibiotics on penaeid shrimp with special emphases on behavioral and biomarker responses. Environ Toxicol Chem. 2010;29(4):929-938.
• Johnson J. Detection and Confirmation of Veterinary Drug Residues in Commercially Available Frozen Shrimp. Master of Science. Louisiana State University and Agricultural and Mechanical College; 2014.
• Done HY, Halden RU. Reconnaissance of 47 antibiotics and associated microbial risks in seafood sold in the United States. J Hazard Mater. 2015;282:10-17.
• Khan M, Lively JA. Determination of sulfite and antimicrobial residue in imported shrimp to the USA. Aquac Rep. 2020;18:100529.
• Davis RP, Davis DA, Boyd CE. A preliminary survey of antibiotic residues in frozen shrimp from retail stores in the United States. Curr Res Food Sci. 2021;4:679-683.
• Thornber K, Verner‐Jeffreys D, Hinchliffe S, Rahman MM, Bass D, Tyler CR. Evaluating antimicrobial resistance in the global shrimp industry. Rev Aquac. 2020;12(2):966-986.
• Heal RD, Hasan NA, Haque MM. Increasing disease burden and use of drugs and chemicals in Bangladesh shrimp aquaculture: A potential menace to human health. Mar Pollut Bull. 2021;172:112796.
• Ware GW, ed. Reviews of Environmental Contamination and Toxicology. Vol 138. Springer New York; 1994.
• Liu Y, Wu Y, Wu J, et al. Exposure to veterinary antibiotics via food chain disrupts gut microbiota and drives increased escherichia coli virulence and drug resistance in young adults. Pathogens. 2022;11(9):1062.
• Hanekamp JC, Bast A. Antibiotics exposure and health risks: chloramphenicol. Environ Toxicol Pharmacol. 2015;39(1):213-220.
• Jenkins E, Cripe J, Whitney BM, et al. An outbreak investigation of salmonella weltevreden illnesses in the united states linked to frozen precooked shrimp imported from india - 2021. J Food Prot. 2024;87(11):100360.

Motion graphics by Avo Media

• allergies
• antibiotics
• cancer
• microbiome
• seafood
• shrimp