Many bacteria are unable to grow at temperatures below 10°C and even psychrotrophic organisms grow very slowly, and sometimes with extended lag phases, when temperatures approach 0°C. Figure 6.2 shows the effect of temperature on the growth rate of the fish spoilage bacterium Shewanella putrefaciens.
What are the factors affecting spoilage of fish?
In addition, the following factors contribute to spoilage of fish.
- High moisture content.
- High fat content.
- High protein content.
- Weak muscle tissue.
- Ambient temperature.
- Unhygienic handling.
Why time and temperature affects the rate of deterioration of fish and other fishery products?
Reducing the temperature at which the fish is kept lowers the rate of deterioration. During chilling the temperature is reduced to that of melting ice, 0 °C/32 °F.
1.2 The preservative effects of chilling fish.
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|Portable refrigeration||Generally static operations|
How does low temperature preserve fish quality?
The purpose of chilling is to prolong the shelf-life of fish, which it does by slowing the action of enzymes and bacteria, and the chemical and physical processes that can affect quality. … Reducing the temperature at which the fish is kept lowers the rate of deterioration.
Which is the optimum temperature to prevent bacterial spoilage of fish and fishery products?
(2004) reported two possibilities for storing fresh fish at low temperatures: (a) cooling at -1° to +4°C, which inhibits the growth of microorganisms and (b) freezing at -18 to -30°C, which completely stops bacteria from growing.
What happens if the temperature of fish is higher than 0 C?
The higher the temperature, the faster the bacteria multiply, using the flesh of the dead fish as food. … For example, fish with a storage life of 15 days at 0°C will keep for 6 days at 5°C and only about 2 days at 15°C before becoming unacceptable.
What is the ideal temperature for storing chilled fish?
Fresh caught or market fresh fish should be stored at a temperature 40°F or below and cooked fish should be kept at a temperature 140°F or higher to keep it outside of the temperature zone in which bacteria, that causes food borne illness, grows quickly. The danger temperature zone is a range between 40°F and 140°F.
Why do fish deteriorate faster?
Fish spoil quickly because they are creatures of the water and therefore of the cold. Deep ocean water is only a few degrees above freezing, and surface waters seldom exceed 70 degrees. … So fish spoil faster than meats, and fatty fish from cold waters spoil the fastest.
What is spoilage in fish processing?
Preservation techniques are needed to prevent fish spoilage and lengthen shelf life. … Spoilage bacteria are the specific bacteria that produce the unpleasant odours and flavours associated with spoiled fish.
How does freezing prevents spoilage of fish and other fishery products?
By lowering the temperature of the dead fish, spoilage can be retarded and, if the temperature is kept low enough, spoilage can be almost stopped. … It is merely the means of preparing the fish for storage at a suitably low temperature. In order to produce a good product, freezing must be accomplished quickly.
What is the effect of freezing on fish?
The main effect of freezing and frozen storage on the quality of fish is a change in texture which is connected with the accompanying rearrange- ment and coagulation of the proteins in the muscle. The tissues become tough because of the denaturation of the proteins.
How can we prevent fish spoilage?
How to prevent spoilage in freshly caught fish
- Keep freshly caught fish alive as long as possible. Monitored live wells or mesh baskets kept underwater keep fish alive longer than a stringer. …
- Clean the fish as soon as possible. …
- Put the fish on ice.
What should be done to avoid damage and spoilage of the fishes before during and after transport?
To minimise spoilage, fish should be kept as cool as possible immediately after catching until processing starts. If tropical fish are chilled with ice, they may be kept in an edible condition for an increased period. The actual length of time depends very much on the type of fish, but may be as long as three weeks.
Which of the following bacteria are carried by fish and are responsible for spoilage?
Whilst the spoilage of fresh and highly salted fish is well understood, much less is known about spoilage of lightly preserved fish products. It is concluded that the spoilage is probably caused by lactic acid bacteria, certain psychotrophic Enterobacteriaceae and/or Photobacterium phosphoreum.
What is freezing in fish preservation?
Freezing preserves the storage life of foods by making them more inert and slowing down the detrimental reactions that promote food spoilage and limit quality shelf life. Freezing is one of the most important processing and preservation methods for fish.