Kochi: Worried about worms in your tuna? Kochi’s marine scientists have a reassuring message for seafood lovers in Kerala: don’t drop the tuna from your plate.

The ICAR-Central Marine Fisheries Research Institute (ICAR-CMFRI), the country’s apex marine fisheries research body based in Kochi, has sought to calm concerns triggered by reports of parasitic worms found in wild-caught tuna in the Atlantic.

For Kerala, where tuna is a familiar catch landed by fishermen and a popular choice on household dining tables and restaurant menus, the message is particularly relevant. It also comes as interest in sushi and other raw-fish dishes grows among diners in the state.

According to CMFRI, there is no reason for consumers to avoid tuna or other commercially available fish simply because parasites have been reported in catches from a particular geographical region.

How the tuna scare began
The concern stems from a marine biology study by researchers from Brazil’s Federal University of Santa Catarina. The study examined wild-caught skipjack tuna (Katsuwonus pelamis) harvested in the Atlantic Ocean off southern Brazil.

The researchers reported parasites in 96% of the samples examined, identifying more than 1,600 individual larvae.

What caught global attention was not merely the presence of parasites, something that can occur naturally in wild fish, but the discovery of larvae in the edible muscle tissue of some fish.

The findings quickly spread online, prompting a much broader question among seafood consumers: If Atlantic tuna can carry parasites, is the tuna on our plates safe?

CMFRI says that conclusion cannot be drawn and asked tuna-lovers to not apply an Atlantic finding to Indian waters

Dr Grinson George, Director of CMFRI, said scientists at the institute regularly examine fish, including skipjack tuna, as part of their biological studies and check for abnormalities and parasites whenever necessary.

“Scientists at CMFRI regularly examine fish, including skipjack tuna, as part of fish biology studies and observe fish for abnormalities and parasites whenever necessary. The fish examined do not show external manifestations of harmful parasitic infestation,” he said.

Marine scientists point out that parasite prevalence is closely linked to local marine ecosystems. Parasites depend on specific environmental conditions and intermediate hosts, including tiny marine crustaceans such as copepods, to complete their life cycles.

Those conditions can vary significantly from one ocean region to another. Parasite patterns are even used by fisheries scientists as biological indicators to distinguish fish stocks from different parts of the world.

“Consumers need not avoid tuna or other commercially available fish merely because parasites have been reported in fish from a specific geographical region,” Dr George said.

What about sushi lovers in Kerala?
The question becomes more important for people who eat tuna raw or lightly cooked.

Sushi, sashimi and other raw or lightly cured seafood dishes have become increasingly popular globally, including among diners in Kerala. When raw fish contains live nematode larvae such as Anisakis, consumption can, in some circumstances, lead to anisakiasis, causing abdominal pain, vomiting and allergic reactions.

That makes proper inspection and handling particularly important when seafood is intended to be eaten raw.

For most Kerala households, however, the traditional cooking process provides an additional layer of protection. CMFRI stressed that proper handling, cleaning and cooking significantly reduce food-safety risks associated with parasites.

Quick and proper evisceration, which means removing the intestines and other internal organs during processing, is an important step. The fish is then cleaned and cooked.

“The intestines and other viscera are normally removed during processing and cleaning. Further, proper cooking kills parasites and significantly reduces any associated food-safety risk,” Dr George said.

So, while the Atlantic study may have given seafood lovers a reason to pause before ordering tuna dishes, Kochi’s marine scientists say there is no reason to write off tuna caught in Indian waters. 

The takeaway from the CMFRI advisory is simple: handle tuna properly, clean it well and cook it thoroughly.