Cleaning and Preparing Shrimps before Packaging: A Complete Guide to Ensuring Freshness and Quality

Cleaning and Preparing Shrimps before Packaging

Shrimps are swimming crustaceans known for their especially delicate, meaty texture. They are rich in protein and have very low calories. Their size can vary from less than 3 centimeters to about 25 centimeters. There are approximately 300 edible species of shrimp found in both saltwater and freshwater environments. The term "prawn" is used in the United Kingdom to refer to shrimp, whereas in the United States, it specifically refers to larger shrimp. The microorganisms present in shrimp include Gram-positive and Gram-negative bacteria, fungi, and viruses. Gram-negative bacteria, such as Vibrio, are widely found in freshwater environments, estuaries, and seas and can cause foodborne infections. These bacteria can produce toxins that lead to serious complications. On the other hand, Gram-positive bacteria, such as Listeria monocytogenes, can thrive in unfavorable conditions and may cause food poisoning. Monitoring and controlling these microorganisms during shrimp production and processing stages are essential to ensuring the safety and quality of the final product.

Parasites and Fungi in the Aquatic Environment and Their Effects on Shrimps

• A number of parasites, particularly protozoa present in water, may affect different stages of shrimp growth. Protozoa typically attach to the gills, cephalothorax, pleopods, and internal organs. At high levels of infection, these protozoa may cause gill obstruction, leading to reduced appetite, slowed growth, impaired movement, and increased susceptibility to infections caused by opportunistic pathogens.
• Fungi exist in aquatic environments, and some aquatic fungi act as opportunistic pathogens for shrimp. Fungal spores and mycelia are observed in damaged tissues, particularly in the gills and appendages of shrimp. Gopalan and colleagues (1980) reported infections of Lagenidium marina and Sirolpidium parasitica in a type of shrimp. Fusarium, caused by Fusarium spp., can affect all developmental stages of certain shrimp species. This disease is observed in ponds where water quality management is poor.

Spoilage or the loss of freshness and safety due to microbial activity, chemical reactions, or environmental factors can lead to changes in texture, flavor, and nutritional value, sometimes resulting in the emergence of diseases and significant economic losses. Shrimp is recognized as a highly perishable food. Although some shrimp may be sold whole with the head, the head is usually the first part to deteriorate. Therefore, most shrimp are sold headless, either with or without the shell. The most common market form of this product is usually frozen. Shelled shrimp require peeling and deveining processes to be ready for consumption. The color of shrimp depends on its species, breed, and living environment. The distinctive smell of fresh shrimp is recognizable, while spoiled shrimp emit a strong, pungent ammonia odor. To reduce odor, shrimp are usually washed and soaked in saltwater. The most important and simplest method to identify fresh shrimp is the firmness of its head. If the shrimp is not fresh, its head detaches easily without any pressure, whereas in fresh shrimp, the head must be pulled upward and pressed to be removed. During shrimp harvesting, attention should also be paid to the mouthparts and gills to ensure they have not accumulated foreign materials or seabed sludge, as the presence of such substances accelerates spoilage. You can also read a comprehensive article written by our company's experts on purchasing fish and seafood packaging machines – various types and prices. In general, the characteristics of fresh and spoiled shrimp are as follows:

Physical Characteristics of Fresh Shrimp:

• The shell color is natural, bright, and free from dark spots.
• The eyes are clear, shiny, and fleshy with a moist, white appearance.
• The legs, shell, and veins are firm and strong.

Physical Characteristics of Spoiled Shrimp:

• In terms of color, blackening occurs on the head, thorax, tail, and shell, while the flesh turns yellowish-green.
•  The eyes are deteriorated, and the head, thorax, tail, antennae, or legs are separated from each other.
•  Spoiled shrimp emit a strong, nauseating ammonia and sulfur odor.

Large shrimp, commonly known as "king shrimp," have lower quality and less flavor due to their older age and firmer muscles. However, because of their larger size, they are more expensive. On the other hand, the smaller and younger the shrimp, the tastier and higher in quality it is.

Initial Preparation after Harvesting

One of the most important stages is the preparation on deck after harvesting, as enzymatic activity in the shrimp's body and the climatic conditions of the fishing areas make it highly susceptible to rapid chemical changes after harvesting, leading to a quick decline in product quality under unfavorable conditions. Under normal conditions, at the end of the operation, the net is lifted from the water, and the harvested shrimp are unloaded onto the deck. At this stage, shrimp are manually separated from other marine species. Then, they are washed with seawater, and if necessary, their heads are quickly removed by deck workers by hand. The shrimp are then placed into special baskets and washed again with seawater.

In the next article, the packaging and methods for extending the shelf life of shrimp are fully explained. If you are active in this field, be sure to stay with us and read it.