Rampant instances of species substitution, mislabeling, and low domestic prices related to U.S. shrimp have led researchers at Florida State University to develop a rapid authenticity test that allows restaurants, marketplaces, and other seafood sellers to identify Atlantic white shrimp quickly and efficiently.
The research process at FSU, located in in Tallahassee, Florida, U.S.A., originally began with a focus on red snapper. David Williams, the CEO of SeaD Consulting in Houston, Texas, U.S.A., partnered with FSU Assistant Professor Prashant Singh and Samuel Kwawukume, a graduate student at the university, to develop a test that would allow seafood industry professionals to quickly identify the DNA of red snapper – a premium species prone to substitution.
After Singh and his team successfully developed an effective red snapper test, they then began modifying the test to work for shrimp.
“The domestic shrimp industry is in a terrible economic situation due to [instances of] imported shrimp substitution,” Williams told SeafoodSource. “There is no money being generated by the U.S. shrimp industry, [which] needs to differentiate wild shrimp to show its economic value.”
As the most popular shellfish in the U.S., mislabeling of farmed shrimp as wild shrimp – and vice versa – is a problem, Williams and Singh said.
A 2014 Oceana study found mislabeling rates of 43 percent in New York City, New York, U.S.A.; 33 percent in Washington, D.C.; and 30 percent in the Gulf of Mexico region, which includes certain cities in the U.S. states of Louisiana, Texas, Florida, and Mississippi.
“As you move to bigger cities, the number increases. Wholesalers are selling the right products, but as you move to restaurants and smaller markets, that’s where a lot of the challenge is,” Singh said.
Atlantic-caught shrimp is very expensive compared to many other species, and when substitution happens, consumers aren’t getting what they paid for, Kwawukume said.
In an attempt to tackle this problem, in 2019, Louisiana passed a law requiring restaurants to identify whether they’re serving imported shrimp. But a recent investigation found no fines have been levied for breaking the law, despite more than 2,600 violations.
Williams said previous methods of testing shrimp are time-consuming and expensive, typically requiring a five-day process that involves shipping samples overnight to a testing lab for extensive DNA extraction and analysis.
Singh said seafood experts can typically identify shrimp species based on physical characteristics, but when shrimp undergo peeling, deveining, and further processing, such as with breaded offerings, identification is challenging.
“When you peel the shrimp, they look similar,” he said. “That’s why [the seafood] industry wants a method they can use at their location without the use of any advanced equipment to confirm the species. They don’t have resources for a fancy lab or expensive equipment.”
The SeaD test is not yet commercially available, but Williams said he expects the it to be available to the industry within six months. The system is currently being beta tested, thanks to financial support from a NOAA Sea Grant.
“All beta testing does is allow us to find the kinks in the testing technology. We will see what hiccups arise, and then we will modify systems to make it perfect,” Williams said.
The new test is being designed to generate on-site results at restaurants, markets, and other facilities in as little as two hours. The test uses a lateral flow strip – or test strip – and a handheld PCR device to extract a DNA sample from the shrimp. After the test strip goes into the DNA sample solution, it produces a band on the strip confirming the presence of a gene-specific to Atlantic white shrimp, indicating a positive result, similar to a pregnancy test.
The test will be able to identify species for raw and cooked samples, according to its creators. Shrimp harvesters could also use the test along with importers and wholesalers to validate the traceability of the shrimp they’re selling and buying, according to Williams.
For shrimp harvesters in the Southern U.S., anything that can help to raise prices would be a welcome shot in the arm, according to Southern Shrimp Alliance Executive Director John Williams (no relation to David Williams). John Williams said low dock prices this season are U.S. shrimpers, even as they record banner catches.
“This is the worst I have ever seen our industry. Fuel prices are high, and shrimp prices are almost nonexistent,” he said.
Low prices have forced some shrimp trawlers to sit out the season, according to Williams.
“The Texas season opened a couple days ago, and a lot of shrimp trawlers are not going to go shrimping,” he said. “This is due to extremely low prices, and some areas are not purchasing from the boats that do go because they can’t resell the shrimp.”
Imports account for around 95 percent of the shrimp sold in the U.S., and eat into the premium domestic wild-caught shrimp should receive in the U.S. marketplace, Williams said.
“If you look at the reasons why wild shrimp is not getting a premium, wild fisheries are difficult,” he said. “Shrimp aren’t all the same size, so the lack of uniformity [is partially to blame].”
At the same time, U.S. shrimp imports are down more than 50,000 metric tons (MT) year over year, and lower prices and higher costs are hammering some overseas aquaculture operations.
Despite the decline in imports, fresh shrimp retail prices rose 6.1 percent to an average of USD 9.12 (EUR 8.30) per pound in the first half of 2023, including a 3.3 percent increase in June to reach an average of USD 9.10 (EUR 8.29) per pound, according to Circana data provided by 210 Analytics.
Photo courtesy of FSU Photography Services
