This post was originally published at My Animal, My Health and has been republished with permission.
For many of us Nigerians, fish is a regular delicacy in our meals. It is also considered a much healthier source of protein compared to red meat products like beef, goat meat and pork. Among the variety of fish options that we have, frozen fish is the most readily available compared to fresh fish. Also, the frozen fish that is sold in our markets contain more variety than we find for fresh fish. Such varieties include the ones locally names such as alaran, express, kote, panla, shawa, etc. For fresh fish, most of them are found and sold around riverine areas. An exception to this is catfish (eja aro in Yoruba) which are commonly bred in artificially-designed fish ponds.
It is important for a fish that is considered deep frozen to remain frozen always to preserve the quality and integrity of the fish. Different varieties of fish remain good in the freezer for different lengths of time. For example, salmon retains its quality for two to three months, while cod stays good for six to eight months. For health and aesthetic reasons, it is important that the fish you eat remains well-preserved without spoilage from lack of preservation and extensive microbial growth and contamination.
It is also important that when you go to the market to shop for fish, you can recognize and differentiate between good and bad fish. You should know that frozen fish can go bad if the freezer stops working during a power outage because bacteria grows rapidly within two hours at warm temperatures. And as expected, the growth of bacteria on frozen or fresh fish causes spoilage and deterioration of the fish. Therefore, at any time you visit the market and fish vendor to purchase your fish, watch out for some key signs and pointers to know if frozen fish has started to go bad or is completely spoiled. Remember, a spoiled bad fish is totally unacceptable for cooking and consumption.
A bad spoiling fish, unfit for consumption has the following characteristics;
- There is a slimy film over the surface of the fish which indicates the presence of actively-growing bacteria.
- The fish has an unpleasant, rotten, off-odor smell. Under no circumstances should you buy a nasty smelling fish and remember, cooking won’t improve the smell.
- The eyes of the fish are cloudy and sunken into the head. For a fresh or well-preserved fish, the eyes are clear, bright, bulging, and shiny. The dull-eyed fish may be safe to eat, but remember that it can’t considered very good for consumption again as it has gone past its prime.
- The gills are dry, covered with sticky slime, grayish-brown in color and they smell bad. For fresh and well-preserved frozen fish, the gills and fins are moist with a nice, bright red color.
- The skin of the old spoiling fish is discoloring and cracked and the fish has already started losing its scales. For fresh and well-preserved fish, the skin is moist, must have a naturally metallic glow and the scales must still be tightly attached to the body.
- The body is soft, grey and inelastic fish in old or bad fish. For fresh fish, the body is firm, has a specific consistency and appearance and when pressed, the body should bounce back.
- The anal opening of old and bad fish sticks out and is yellow-brown in color. For fresh or well-preserved fish, the belly is shiny and undamaged, and the anal opening is tight.
Important things to note about preservation of fresh and deep-frozen fish
Note that fresh fish is easily perishable. It is kept on ice 10-15 days or in coolers under the temperature of around 0°C. This fish is best to be cleaned and gutted immediately after being caught. Quality is best preserved by placing fish in shallow crates after a catch, mixing it with ice and selling it the next day. Fish must be entirely covered with ice and the crate bottom must be permeable so the water can leak out. When keeping fish in freezers, temperature must not be lower than -4°C to -6°C, otherwise the fish freezes, large ice crystals are formed, tissue is damaged and quality reduced. For frozen or deep-frozen fish, it must not be kept in storage longer than six months. Expiration date must be regularly checked as well as the conditions and quality of frozen products.
Now that you know how to differentiate between good and bad fish at the market…… You are welcome!