102
tenderness decreased with storage during storage. It is reported that crayfish
should be kept in less than 7 days on ice as in retail conditions (Tseng et al.
2002). Lobster (N. norvegicus) tails (within their shells) were placed in plastic
resealable bags and either kept continuously on ice or held at 16 °C for 4, 8 or
24 h prior to storage on ice. The effects of icing delays on the quality of tail meat
were evaluated. Changes in K-values, microbial load, muscle pH and TMA indicated that the delay to icing should be no more than 4 h (at 16 °C) to ensure that
quality is not compromised during subsequent post-harvest storage (Albalat
et al. 2011). Delays before icing and inadequate icing increase the commercial
rate of rejection. Trawled Nephrops are highly perishable and need to be promptly
iced at sea and landed soon after catching to ensure high yields of best quality
product (Anonymous 1994).
Studies on the preservation of lobsters in the cold have shown that not only
raw lobsters but also cooked lobsters can be stored in cold conditions. In one
study, the crayfish (P. clarkii) were washed with tap water, then cooked in boiling
water at 95–100 °C for 180–190 s and then cooled rapidly with cold water. After
the peeling, the crayfish were packed under modified atmospheres and then
stored at 2 °C. According to the results of the study, it was determined that the
shelf life of crayfish packaged in modified atmosphere can be increased from 6
to 12 days at 2 °C compared to the samples packed in atmospheric air used as
control (Cremades et al. 2011). In a similar study conducted on precooked and
peeled red claw crayfish (Cherax quadricarinatus), modified atmosphere packaging almost totally inhibited the growth of aerobic bacteria and coliforms in
crayfish stored at 2 °C compared with aerobic and vacuum packaging (Chen
et al. 2007; Chen and Xiong 2008). Furthermore, it has been reported that the
shelf life of N. norvegicus can be extended from 6.5 to 13 days when packaged
in MAP (10% O 2 , 80% CO 2 and 10% N 2 ) and storage temperatures do not exceed
1 °C (Gornik et al. 2013).
Rapid chilling of seafood after harvest is important for both quality and safety.
Icing is the most common cooling method for seafood. Slurry ice has been used in
recent years in addition to traditional icing methods for fast and effective cooling.
Slurry ice also has the advantages of not causing physical damage, being able to
cool to lower temperatures, increasing the shelf life of the product and reducing
dehydration. It has been found that Norwegian lobster (Nephrops norvegicus) stored
on slurry ice maintains its sensory quality better and has a longer shelf life compared to those stored with flake ice (Aubourg et al. 2007; Losada et al. 2006).
Freezing of Lobsters
Freezing is an important method for preservation of seafood since frozen product
can be stored for long periods by preventing microbial spoilage. Freezing inhibits
the activity of microorganisms that cause food spoilage and food spoilage. Lowering
the temperature below freezing inhibits the growth and activity of most microorganisms. Decreasing the storage temperature greatly slows down enzymatic and bio2 Crustacean Shellfish
tenderness decreased with storage during storage. It is reported that crayfish
should be kept in less than 7 days on ice as in retail conditions (Tseng et al.
2002). Lobster (N. norvegicus) tails (within their shells) were placed in plastic
resealable bags and either kept continuously on ice or held at 16 °C for 4, 8 or
24 h prior to storage on ice. The effects of icing delays on the quality of tail meat
were evaluated. Changes in K-values, microbial load, muscle pH and TMA indicated that the delay to icing should be no more than 4 h (at 16 °C) to ensure that
quality is not compromised during subsequent post-harvest storage (Albalat
et al. 2011). Delays before icing and inadequate icing increase the commercial
rate of rejection. Trawled Nephrops are highly perishable and need to be promptly
iced at sea and landed soon after catching to ensure high yields of best quality
product (Anonymous 1994).
Studies on the preservation of lobsters in the cold have shown that not only
raw lobsters but also cooked lobsters can be stored in cold conditions. In one
study, the crayfish (P. clarkii) were washed with tap water, then cooked in boiling
water at 95–100 °C for 180–190 s and then cooled rapidly with cold water. After
the peeling, the crayfish were packed under modified atmospheres and then
stored at 2 °C. According to the results of the study, it was determined that the
shelf life of crayfish packaged in modified atmosphere can be increased from 6
to 12 days at 2 °C compared to the samples packed in atmospheric air used as
control (Cremades et al. 2011). In a similar study conducted on precooked and
peeled red claw crayfish (Cherax quadricarinatus), modified atmosphere packaging almost totally inhibited the growth of aerobic bacteria and coliforms in
crayfish stored at 2 °C compared with aerobic and vacuum packaging (Chen
et al. 2007; Chen and Xiong 2008). Furthermore, it has been reported that the
shelf life of N. norvegicus can be extended from 6.5 to 13 days when packaged
in MAP (10% O 2 , 80% CO 2 and 10% N 2 ) and storage temperatures do not exceed
1 °C (Gornik et al. 2013).
Rapid chilling of seafood after harvest is important for both quality and safety.
Icing is the most common cooling method for seafood. Slurry ice has been used in
recent years in addition to traditional icing methods for fast and effective cooling.
Slurry ice also has the advantages of not causing physical damage, being able to
cool to lower temperatures, increasing the shelf life of the product and reducing
dehydration. It has been found that Norwegian lobster (Nephrops norvegicus) stored
on slurry ice maintains its sensory quality better and has a longer shelf life compared to those stored with flake ice (Aubourg et al. 2007; Losada et al. 2006).
Freezing of Lobsters
Freezing is an important method for preservation of seafood since frozen product
can be stored for long periods by preventing microbial spoilage. Freezing inhibits
the activity of microorganisms that cause food spoilage and food spoilage. Lowering
the temperature below freezing inhibits the growth and activity of most microorganisms. Decreasing the storage temperature greatly slows down enzymatic and bio2 Crustacean Shellfish