Now, a tool to check shrimp mislabelling

Restaurants or marine products processing firms that substitute prized shrimp varieties with inferior quality ones, beware. Fisheries scientists in Tamil Nadu have developed a robust technique that will help regulators detect mislabelling and similar frauds.

Researchers led by Geevaretnam Jeyasekaran at the Fisheries College and Research Institute (FCRI) at Thoothukkudi have developed a sophisticated lab-based PCR test that is capable of differentiating four commercially important shrimp varieties from cheaper copycats.

“When you go to a restaurant and order a pan-cooked tiger shrimp curry, there is a possibility that what you get may not have tiger shrimp but contains a cheaper cousin, say Pacific white shrimp,” said Jeyasekaran, an FCRI scientist, who led the study. This is because once the head and tail are removed, different species of shrimps look similar and their distinct odour and taste are often masked by pungent spices,” he said.

A major concern “Food authenticity is an issue of major concern for food authorities all over the world, as mislabelling is a major commercial fraud,” the scientist said.

Such mislabelling is quite rampant in the shrimp processing industry. In 2014-15, India earned two-thirds of its total seafood export earnings, worth $5.5 billion, from frozen shrimps.

“Those who are out there to make a quick buck mix cheaper varieties with prized ones and sell them as much-sought-after varieties,” Jeyasekaran said. The inferior varieties, containing lesser nutrients, are 25 to 30 per cent cheaper than the popular ones.

In many countries, the enforcement of correct labelling is emerging as a mandatory requirement.

According to Jeyasekaran, in developed countries, nearly 50 per cent of the shrimps sold are in processed form, and often, they do not bear an appropriate label regarding the species or farming method (caught from wild or farmed).

In 2014, DNA testing by the US-based not-for-profit organisation Oceana found that 30 per cent of 143 shrimp products from 111 grocery shops and restaurants were misrepresented.

The technique that Jeyasekaran and his team developed, however, can bring an end to this problem as it is capable of authenticating the shrimp species and thus protect consumers from economic fraud. The DNA-based technique, reported online in the journal Food Chemistry recently, has been developed for the first time in India and is suitable for testing the presence of popular Indian varieties such as giant tiger shrimp, Indian white shrimp, flower shrimp and Pacific white shrimp.

Apart from Jeyasekaran, other FCRI researchers involved in the project were Lidya Wilwet, Robinson Jeya Shakila, Balasubramanian Sivaraman and Pandurangen Padmavathy. More importantly, the tool is capable of identifying the species from any kind of sample — whether it is cooked, fried, canned or raw.

“This is because we extract the DNA from the shrimp muscle, which remains intact,” he said.

The Thoothukkudi institute is already a centre for certifying seafood products in India.

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