Maneka Sanjay Gandhi
Health and fitness advisors often emphasise on seafood for muscles, high protein, weight loss, etc. But few have studied the health risks that come with eating seafood.
Mali Ston, an Adriatic Sea coastal town in Croatia is known for its farmed oysters, of which five million sell every year. For centuries, rows of oyster-filled underwater farm beds have spread through the bay. An annual oyster tasting feast has tourists pour in. In 2019, they have had to cancel it because the Institute for Marine and Coastal Research in Dubrovnik detected norovirus in the oysters. The virus has been caused by sewage from the town pouring in all these years into the bay. Norovirus is a dangerous virus, causing over 20 million illnesses and hundreds of deaths annually. Symptoms, which include chronic vomiting and diarrhoea, can become very severe, very quickly, requiring emergency treatment.
Flame-grilled carp, seasoned with sauces and known as masgoof, is Iraq’s national delicacy. Iraq produces 29,000 tonnes of carp annually, grown in farms along the Euphrates River. In 2018, millions of carp died overnight in fish farms. Samples of dead fish, water and sediment, sent to laboratories, confirmed that fish died of a virus caused by low temperatures, overstocking of fish farms, and polluted river water. Warnings have been issued by the government not to eat carp.
Seafood is responsible for a large proportion of food-borne illnesses. These are caused by a variety of bacteria, viruses, and parasites. Chemicals, metals, marine toxins, and infectious agents have been found in seafood. The illnesses caused by these agents range from mild gastroenteritis to life-threatening conditions.
Seafood includes molluscs, finfish, marine mammals, fish eggs, and crustaceans. Some seafood commodities are inherently more risky than others, depending on the environment from which they come, their mode of feeding and how they are prepared and served. All seafood are susceptible to surface or tissue contamination. Bivalve molluscs feed by filtering large volumes of seawater. During this process, they can accumulate and concentrate pathogenic microorganisms. Contamination of seafood by pathogens can occur when areas are contaminated with human sewage. Additionally, seafood may become contaminated during handling, processing, or preparation.
Seafood has been implicated in so many outbreaks of illnesses that data is collected by official agencies in every country. The Food and Veterinary Office of the European Union has initiated a Rapid Alert System for food. The source of danger and country of origin are reported. Between 1992 and November 1997, the 71 seafood alerts from this system represented 42.5 per cent of all food alerts. The seafood products implicated mussels, tuna fish products, oysters, squid, raw sole, shrimp, octopus, shellfish, crawfish, scallops, cuttlefish, anchovy, Nile perch, bivalve molluscs, king prawn, salmon, mullet fillets, canned fish, clams. These alerts have doubled and tripled since.
Thirty-three different countries had exported seafood on which an alert was reported. The highest alerts were received on fish sent from India.
In Canada, 29 different species of fish and/or seafood products, were implicated in seafood-borne illnesses. The top six in number of outbreaks were mussels, clams, tuna, barracuda and marlin. Ten countries, that had exported these fish to Canada, were implicated, including India.
Some of the pathogens responsible for sea food infections include Vibrio bacteria which cause outbreaks of gastroenteritis. Symptoms include watery diarrhoea, abdominal cramps, nausea, and vomiting. V vulnificus is particularly virulent, especially among patients with liver disease and iron storage disorders. Infections can lead to sepsis and severe wound infections. Salmonella bacteria causes acute gastroenteritis, with symptoms including diarrhoea, abdominal cramps and fever. Seafood-associated outbreaks have been caused by fish, shrimp, oysters, and clams.
Shigella bacteria in fish comes from sewage in the water. Complications include seizures in young children, toxic megacolon, Reiter’s syndrome, and hemolytic-uremic syndrome.
Norovirus infection is characterised by diarrhoea, vomiting, nausea, abdominal cramps, headache, myalgias, and low-grade fever. Seafood, harvested from sewage-contaminated waters, has caused large outbreaks of norovirus gastroenteritis.
Hepatitis A virus is the most serious viral infection associated with seafood consumption. Outbreaks of hepatitis A virus infections, associated with oysters and clams, have been known since the 1960s.
Contamination through sewage is a very common practice around the world, especially in India. Overboard sewage discharge into seafood harvest areas, illegal harvesting from sewage-contaminated waters, and sewage runoff from land after heavy rains or flooding, are the many ways in which this happens.
Right from the production to packaging, transport and consumption, seafood is likely to be contaminated. Intensive fish farming has enhanced the incidence of seafood diseases.
With a heavily globalised food trade, the long journey seafood travels before reaching our plates, drastically increases the chances of it becoming dangerously contaminated. It is important that you understand the consequences of seafood consumption. If not for reasons of sustainability and animal welfare, look at seafood in terms of your own immediate health.
