The process may help parties such as importers, customs officials and retailers trace globally traded seafood back to its source.
Traceability of aquacultured shrimp depends on records from farmers and processing plants. There is no objective way of verifying such records leaving opportunities for mislabeling and fraud, said scientists.
The study, by WWF researchers, Auburn University and Ocean University of China, looked at farmed Pacific white shrimp (Litopenaeus vannamei).
Researchers said it is likely that 100% accuracy could be achieved with a larger database.
Goal of farm origin
Aaron McNevin, director of sustainable food at WWF, said elemental profiling is one step closer to the goal of farm origin.
“Traceability allowing consumers to know where their shrimp came from largely isn’t possible in the mainstream markets today. Without knowing where a product is coming from, it is impossible to determine if the environment at a farm is being compromised or if workers are being mistreated.”
The US imported 567,551 tons of shrimp valued at $6.7bn during 2014 from 39 countries, according to the National Oceanic and Atmospheric Administration (NOAA).
A total of 23 elements, including essential macro- and micro-nutrients and non-essential trace elements, in headless shell on shrimp (HLSO) samples were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES).
It was not possible to definitively determine which elements are the best descriptors for each region.
Thirty shrimp samples each for India and Vietnam and 60 for Thailand were collected on a single date between May and August 2016.
Sodium (Na) ranged from 2,849 to 5,946 mg kg−1 in India, 4,393 to 9,093 mg kg−1 in Vietnam, and 3,445 to 7,842 mg kg−1 in Thailand.
The ranges for trace elements was greater with the concentration of iron ranging from 0 to 178 mg kg−1 in India, 5-309 mg kg−1 in Vietnam, and 1-313 mg kg−1 in Thailand.
Explorative principal component analysis (PCA) was done to reduce dimension and interpret the data. Stepwise discriminant analysis (SDA) was used to select variables that contributed the most to discrimination between groups.
Less accurate than country-level comparison
Elemental profiling was tested as a way of differentiating shrimp produced to area of origin for two areas in Thailand, three provinces in Vietnam and India.
“The separation of shrimp among two production areas in Thailand and three areas in Vietnam was much less accurate (83.3–88.3%). But, the database was obviously less than for the country-level comparisons,” said the researchers.
“We suspect that elemental profiling might be effective in separating shrimp from distinct areas in a given country if more data were available.”
Claude Boyd, professor of Aquaculture and Aquatic Sciences at Auburn University, said it has done elemental profiling in the southeastern US and it worked well for catfish and shrimp so the logical choice was to expand to major farming countries.
“This research demonstrated that we also have some ability to differentiate shrimp from provinces and states in countries, albeit not to the same level of confidence as the country.”
Source: Food Control Volume 80, October 2017, Pages 162–169
“Assessment of elemental profiling for distinguishing geographic origin of aquacultured shrimp from India, Thailand and Vietnam”
Authors: Li Li, Claude E. Boyd, Phoebe Racine, Aaron A. McNevin, Benjaporn Somridhivej, Hang Ngo Minh, Huynh Quoc Tinh, Ravibabu Godumala