Fish, like most other protein foods, is susceptible to spoilage if not handled and stored properly.
According to the Food and Agriculture Organization of the United Nations, global fish consumption is estimated at 20.5% per capita and is expected to increase in the coming years as fish is an important source of nutrition for many people around the world, providing essential protein and nutrients such as vitamin A, calcium, iron and omega-3 fatty acids.
Across the Caribbean and Latin America, fish sales have been steadily increasing, not only because fish is an important source of nutrition, but also because the fish industry provides income to many people, whether they are fish farmers, fishermen or indirectly involved in the processing and sale of fish for food.
Fish fraud is a growing public health concern
Fish, like most other protein foods, is prone to spoilage if not handled and stored properly, but the cost per kilogram ranges from $849.82 to $2,059.70 in some countries, such as Jamaica. To secure economic profits and reduce the chance of spoilage, it is common practice for traders to adulterate fish with substances such as formaldehyde (formalin). They may use ice laced with formalin to hide poor quality fish, or in some cases pass the fish itself through a mixture of formaldehyde (formalin) and water. Fish adulteration is a food crime, and what is less well known is the fact that it poses serious risks to human health, with an estimated 22% of food produced each year being adulterated. Human cancer, kidney and liver failure, and allergies have all been linked to these fraudulent practices.
Why do fish traders add formaldehyde (formalin) to their fish?
To improve the appearance of the fish
•Avoid purchasing ice required to minimize fish spoilage due to temperature violations
• There is a lack of infrastructure to preserve the quality of fish, for example markets lack refrigeration facilities to keep these foods safe and hygienic.
General health effects of excessive levels of formaldehyde (formalin) in fish
Formaldehyde in fish can be naturally occurring or economically motivated, leading to food fraud. Too much formaldehyde in fish can cause gastrointestinal symptoms such as vomiting, diarrhea, dizziness, nausea, and in more severe cases, death in people who eat fish meal adulterated with formaldehyde.
How to Tell if Your Fish Has Been Contaminated with Formaldehyde (Formalin)
Freshly caught fish have the following characteristics:
•Their eyes are bright and protruding, making them appear alive even when dead.
•It has a slight seaweed scent and no pungent odor.
•If there is no scale, there is little or no missing scale.
•Bright red closed gills.
•Evidence of fresh blood along the spine.
•Fresh fish is firm to the touch and has little or no slime.
Stale, spoiled or adulterated fish:
• They may have an odd odor, their gills may be open, and they may appear gray or discolored instead of bright red, especially if they have been laced with formaldehyde (formalin).
• They are dry in appearance, have a rubbery texture and hard scales.
•The eyes are white, cream or grey.
Excessively stiff body
•Signs of spoilage such as a strong odor will appear.
Factors affecting fish spoilage
There are three main causes of fish spoilage: enzymatic autolysis, oxidation, and microbial action. Enzymatic spoilage occurs soon after the fish is caught, followed by death. These enzymes are responsible for the changes that occur in the texture of the fish. Immediate storage on ice at or below 5 degrees can slow down the activity of these enzymes. Oxidative spoilage is responsible for the changes in color, flavor, and nutritional value of the fish, and also causes the off-odor of spoiled fish. To avoid these changes, it is recommended to store fish at a temperature of 5 degrees, including adding ice to the fish during transportation and storage. The quality and safety of fish is also affected by the growth and metabolism of bacteria in and on the surface of the fish flesh, which can also cause quality deterioration such as odor and taste.
Advice for consumers
•Buy fish only from reputable sources, as fish and other seafood contaminated with formaldehyde (formalin) will not be safe to cook.
• Know the characteristics of fresh fish and make sure the fish is stored in hygienic conditions before purchasing.
•See a doctor if you experience vomiting, nausea, diarrhea, stomach cramps, dizziness, or other similar symptoms after eating fish or seafood. In most cases, these symptoms appear within 6 hours of consuming the adulterated food.
Dr. Carlene Atkinson is a public health specialist and lecturer at the School of Public Health at the University of Technology, Jamaica.
