Published Apr 25, 2026 | 2:38 PM ⚊ Updated Apr 25, 2026 | 2:38 PM
AI-generated representational image.
Synopsis: Two months after two Kollam family members died following a seafood meal in Vizhinjam, investigators say food poisoning is unlikely. A chemical report points instead to marine biotoxins in fish eggs, which routine tests miss. These heat‑stable toxins, like tetrodotoxin, can cause rapid neurological symptoms and fatalities, highlighting gaps in detection and the need for stronger coastal monitoring.
More than two months after two members of a Kollam family died following a meal at a seafood restaurant in Vizhinjam, investigators say food poisoning is unlikely to have caused the deaths.
A recent chemical examination report instead points to the possible presence of naturally occurring marine toxins—substances that routine food safety tests often fail to detect.
The incident dates back to 16 February, when six members of a family from Nilamel in Kollam district dined at Asmak Hotel near the Muhiyuddeen Mosque in Vizhinjam. Soon after leaving the restaurant, several of them began experiencing severe discomfort, including vomiting.
Shaji (42) and his mother-in-law, Rasheeda Beevi (58), later died after being admitted to hospitals in Thiruvananthapuram and Parippally. Shaji’s wife, Regimol, was hospitalised in critical condition, while two children in the group remained unaffected.
At the time, the deaths were widely suspected to be the result of food poisoning. The hotel was temporarily shut as a precaution, and food safety officials collected samples for testing.
Also Read: Chennai hospital reports impulsive ingestion of rat poison among young adults
Subsequent laboratory analysis, however, failed to detect bacteria typically associated with food poisoning. Postmortem findings also did not support the initial suspicion. Investigators examined leftover food, water samples from the restaurant, and even fish sourced from markets in Tamil Nadu.
None showed signs of contamination linked to conventional foodborne illness. Complicating matters further, samples of the exact food consumed by the family were not available for testing.
However, one detail stood out during the inquiry: all affected family members had consumed fish eggs served at the restaurant, which later became central to the investigation.
The chemical report suggests that marine biotoxins present in the fish eggs may have triggered the fatal reaction. These toxins, produced by certain marine organisms, can accumulate in seafood and are not destroyed by cooking.
A senior Food Safety Department official, speaking on condition of anonymity, said, “We could not establish any bacterial contamination despite extensive testing. Given the clinical symptoms and the common food item consumed, marine toxins remain the most plausible explanation at this stage.”
However, officials didn’t specify what kind of marine toxin had resulted in the deaths.
Marine toxins are not uncommon in tropical waters. They are often produced by microscopic algae during harmful algal blooms and can accumulate in fish and shellfish without altering taste, smell, or appearance.
Compounds such as tetrodotoxin and ciguatoxin are known to be particularly dangerous. Heat-stable in nature, they survive cooking and can affect the nervous and cardiovascular systems within minutes of ingestion.
Symptoms reported in such cases include nausea, vomiting, numbness around the mouth, a sensation of floating, weakness, and, in severe instances, paralysis and respiratory failure. Medical literature notes that fatal outcomes can occur within a short span, depending on the level of exposure.
One of the difficulties in confirming such cases lies in the lack of routine diagnostic tools.
Most laboratories do not have the capacity to detect marine toxins, and diagnosis is often based on clinical symptoms and food history.
“There is still a gap in our ability to conclusively test for many of these toxins,” the Food Safety official added. “That makes prevention and surveillance all the more important.”
Food safety authorities had earlier begun exploring the possibility of algal toxins after consultations with treating doctors and in light of recent findings in the region.
Officials pointed to earlier instances where ciguatoxin had been identified in fish samples, including red snapper sourced from the Tamil Nadu coast.
Such toxins originate from dinoflagellates—microscopic algae common in warm, coastal waters.
A scientist with the Central Marine Fisheries Research Institute (CMFRI) noted, “Marine biotoxins are part of a complex ecological cycle. Fish can accumulate them without any visible signs. What makes them particularly concerning is that they remain active even after cooking and are difficult to detect without specialised testing.”
Sudhir Kumar, Senior Neurologist at Apollo Hospitals Hyderabad, told South First that certain marine organisms naturally harbour toxins as a biological defence mechanism to protect themselves from predators. He said this is fundamentally different from toxin exposure caused by environmental pollution, such as mercury contamination seen in Minamata disease in Japan.
He added, compounds like tetrodotoxin are not man-made contaminants but are intrinsically present in specific marine species.
He noted that the most well-known source of this toxin is the puffer fish, where it is concentrated in organs such as the liver, intestines, skin, and eggs. He further pointed out that other marine creatures, including certain crabs and rare species like the blue-ringed octopus, may also carry similar toxins.
What makes tetrodotoxin particularly dangerous, he said, is its extremely high potency—even a dose as small as 1–2 milligrams can be life-threatening.
Explaining the clinical effects, he said the toxin produces a rapidly progressing neurological syndrome. Symptoms can begin within 10 to 20 minutes of consumption, initially presenting as numbness or tingling around the lips and tongue, followed by weakness that typically starts in the lower limbs and ascends upwards. Unlike many forms of food poisoning, he added, gastrointestinal symptoms may not be prominent.
Instead, the toxin affects peripheral nerves, leading to paralysis, difficulty in speaking and swallowing, and eventually respiratory failure if not managed promptly. Importantly, he emphasised, the brain remains unaffected, and patients are often fully conscious throughout the progression.
He also highlighted that there is currently no specific antidote for tetrodotoxin, and management is primarily supportive. If the patient presents early, he said, gastric decontamination may help reduce toxin absorption.
However, in most cases, intensive care becomes crucial, particularly ventilatory support to manage respiratory failure. The critical window, he explained, is usually the first 48 to 72 hours—patients who survive this period often recover completely, as the toxin’s effects are reversible once it is cleared from the body.
This, he concluded, distinguishes it from many other neurological conditions, as there is typically no lasting damage if timely supportive care is provided.
Marine biotoxins are increasingly recognised as a global food safety issue. They can lead to a range of illnesses, broadly classified into paralytic, diarrhoeic, neurotoxic, and amnesic shellfish poisoning syndromes.
These toxins are produced by a wide range of marine organisms, including algae and certain bacteria, and can accumulate in seafood through the food chain. Fish, shellfish, and even organisms like octopus and sea urchins can act as carriers.
Beyond human health, such toxins also disrupt marine ecosystems, affecting fish populations and biodiversity. Economic losses in fisheries and tourism often follow outbreaks linked to contaminated seafood.
Also Read: Food poisoning, illness, deaths at Telangana government-run schools, hostels
Off India’s long and busy coastline, the idea of testing fish for toxins the moment they are hauled in is no longer far-fetched. The science is moving in that direction. But on an actual fishing boat, far from shore and short on space, it remains largely impractical.
Researchers have developed rapid test kits—known as lateral flow assays—that can detect certain marine toxins within an hour. They work much like familiar diagnostic strips used during the pandemic. In controlled conditions, they have shown promise for identifying threats such as ciguatoxins and those responsible for paralytic shellfish poisoning.
The difficulty begins once the fish is out of the water. Unlike testing seawater, checking a fish for toxins involves several steps. A small portion of tissue has to be crushed, mixed with solvents like methanol to extract any toxin present, and only then applied to the test strip. That sequence, simple enough in a lab, becomes cumbersome on a moving vessel where equipment is limited and conditions are unpredictable.
An official with the Fisheries Department said, “Along India’s coasts, the risks themselves are shifting. Warmer waters are creating favourable conditions for harmful algal blooms, the source of many marine toxins. Incidents linked to these blooms are being reported more often than before.”
The official also stated that ciguatera fish poisoning, once associated mainly with tropical regions in the Pacific and Caribbean, has begun appearing in Indian waters.
Cases have been documented along the coasts of Mangaluru, Thoothukudi and parts of Kerala, often linked to large reef fish such as red snapper and barracuda.
Shellfish poisoning remains a recurring concern on the southwest coast. Blooms of toxin-producing algae—particularly species that trigger diarrhetic and paralytic shellfish poisoning—have led authorities to periodically halt the collection of mussels and clams. These seasonal restrictions, though disruptive, are based on monitoring data and are meant to prevent outbreaks.
There are also sporadic risks tied to species like pufferfish, which carry tetrodotoxin. While not commonly consumed, accidental ingestion continues to be reported in some coastal communities.
Government-backed monitoring plays a crucial role in managing these threats. Agencies such as Central Marine Fisheries Research Institute and Centre for Marine Living Resources and Ecology track algal blooms using satellite imagery and field sampling. When a potentially dangerous bloom is detected, advisories are issued to fishermen and coastal authorities.
A scientist at CMFRI said the gap between laboratory capability and field use is still wide.
“We can detect these toxins with high precision once samples reach the lab. Translating that into something a fisherman can reliably use at sea is a different challenge altogether. It’s not just about the test strip—the preparation, the handling, the conditions—all of it matters,” the official said.
(Edited by Amit Vasudev)
