78
During the freezing of the meats, cell membranes are damaged, which leads to a
decrease in water holding capacity and a loss of cooking loss (Lagerstedt et al. 2008).
It is reported that the aggregation and denaturation of proteins in crab muscle is heat
induced and leads to loss of water retention capacity of proteins. In addition, denatured proteins formed during frozen storage are susceptible to heat denaturation.
Changes in Lipids
Lipid oxidation can be induced by frozen storage. Ice crystals formed during the
freezing process can destroy the cells and release pro-oxidants for lipid oxidation,
particularly free iron (Benjakul and Bauer 2001). The increase of thiobarbituric acid
and values of the sea crab (P. pelagicus) (Subramanian 2007) and mud crab (Scylla
serrata) (Benjakul and Sutthipan 2009) was determined during frozen storage.
2.2.4.5 Pasteurizing and Canning
Pasteurization is a heat treatment below 100 °C, which generally means light heating. Pasteurization increases the shelf life of crabs in refrigerated storage. The crab
meat is commercially pasteurized at 85 °C and stored under refrigerated conditions
(Innocen 2014). From this definition it is understood that the product is non-sterile
and can therefore continue to contain microorganisms. As a result, pasteurized
products must be kept in continuous cold so that the surviving microorganisms do
not multiply very quickly. Crab meat is an excellent medium for bacterial growth
due to its high water-activity, moderate pH, and low salinity. Most of the bacteria
present on the crab are located on the shell, viscera, and gills. Pasteurization of
foods other than crabmeat is often defined in terms of a target organism. There is no
target organism for the pasteurization of crabmeat. The process evolved based on
shelf life extension (Hackney et al. 1991). Crab meat is at risk for Clostridium botulinum, especially for type E. Contamination may occur due to post-cooking processes and environmental influences. The pasteurized crab meat is packaged with a
hermetically strong seal, pasteurized, and stored in cold conditions. Pasteurized or
canned crab products are marketed as jump, jumbo lump, back fin, claw meat and
claw finger (Biji et al. 2013). Pasteurizing the crab can extend the shelf life at refrigerated temperatures from 70–10 days to 12 months (Matiella and Hsieh 1990).
In a study where microbial analyses were conducted at different control points in
the pasteurized crab processing line, it was determined that the pasteurization process had a positive effect on the microbial quality of the final product
(Olgunoglu 2010).
According to Codex Alimentarius international food standards canned crab is
defined as “Canned crab meat is prepared singly or in combination from the leg, claw,
body and shoulder meat, from which the shell has been removed, of any of the edible
species of the sub-order Brachyura of the order Decapoda and all species of the family Lithodidae”. Canned crab meat is placed in hermetically sealed containers and
subjected to sufficient treatment to ensure commercial sterility (Anonymous 1981).
2 Crustacean Shellfish
During the freezing of the meats, cell membranes are damaged, which leads to a
decrease in water holding capacity and a loss of cooking loss (Lagerstedt et al. 2008).
It is reported that the aggregation and denaturation of proteins in crab muscle is heat
induced and leads to loss of water retention capacity of proteins. In addition, denatured proteins formed during frozen storage are susceptible to heat denaturation.
Changes in Lipids
Lipid oxidation can be induced by frozen storage. Ice crystals formed during the
freezing process can destroy the cells and release pro-oxidants for lipid oxidation,
particularly free iron (Benjakul and Bauer 2001). The increase of thiobarbituric acid
and values of the sea crab (P. pelagicus) (Subramanian 2007) and mud crab (Scylla
serrata) (Benjakul and Sutthipan 2009) was determined during frozen storage.
2.2.4.5 Pasteurizing and Canning
Pasteurization is a heat treatment below 100 °C, which generally means light heating. Pasteurization increases the shelf life of crabs in refrigerated storage. The crab
meat is commercially pasteurized at 85 °C and stored under refrigerated conditions
(Innocen 2014). From this definition it is understood that the product is non-sterile
and can therefore continue to contain microorganisms. As a result, pasteurized
products must be kept in continuous cold so that the surviving microorganisms do
not multiply very quickly. Crab meat is an excellent medium for bacterial growth
due to its high water-activity, moderate pH, and low salinity. Most of the bacteria
present on the crab are located on the shell, viscera, and gills. Pasteurization of
foods other than crabmeat is often defined in terms of a target organism. There is no
target organism for the pasteurization of crabmeat. The process evolved based on
shelf life extension (Hackney et al. 1991). Crab meat is at risk for Clostridium botulinum, especially for type E. Contamination may occur due to post-cooking processes and environmental influences. The pasteurized crab meat is packaged with a
hermetically strong seal, pasteurized, and stored in cold conditions. Pasteurized or
canned crab products are marketed as jump, jumbo lump, back fin, claw meat and
claw finger (Biji et al. 2013). Pasteurizing the crab can extend the shelf life at refrigerated temperatures from 70–10 days to 12 months (Matiella and Hsieh 1990).
In a study where microbial analyses were conducted at different control points in
the pasteurized crab processing line, it was determined that the pasteurization process had a positive effect on the microbial quality of the final product
(Olgunoglu 2010).
According to Codex Alimentarius international food standards canned crab is
defined as “Canned crab meat is prepared singly or in combination from the leg, claw,
body and shoulder meat, from which the shell has been removed, of any of the edible
species of the sub-order Brachyura of the order Decapoda and all species of the family Lithodidae”. Canned crab meat is placed in hermetically sealed containers and
subjected to sufficient treatment to ensure commercial sterility (Anonymous 1981).
2 Crustacean Shellfish