101
Pre-treatments in Processing of Lobsters
Selection
Selection is the sorting process that separates lobsters to be kept alive and discarded.
The selection process is essential for maintaining quality. Sick or dead lobsters
should be removed. Because they will die in a short time and then deteriorate. The
easiest way to separate dead and sick animals is to keep lobsters individually in
separate tanks or tank-like sections. Recently moulted lobsters should be removed
from the storage tank due to cannibalism risk. Even if these lobsters survive, their
value will be reduced as their legs and antennae will be eaten (Jacklin and
Combes 2007b).
Grading
Grading is a selection process that separates lobsters into sizes and genders to meet
market demands. In the sale of live lobsters, the buyer may have specifications for
size and gender. In this case, such requests can easily be met by the storage facilities
organizing separate tanks for certain grades (Jacklin and Combes 2007b).
Chilling of Lobsters
Crustaceans must be chilled to the point of insensitivity (unconsciousness) prior to
being killed. They should be stored in a refrigerator at approximately 5 °C, both for
food safety reasons and for the welfare of the animal. If lobsters are kept at −10 to
−18 °C for 45 min they become unconscious but do not freeze.
It is reported that in N. norvegicus, the storage temperature is the most crucial
factor affecting microbial growth, microbial activity, and spoilage potential.
Therefore, N. norvegicus tails should be stored in a cool environment immediately
after catch (even prior to ‘tailing’) and should be stored in ice (at 0 °C) as soon as
possible after on-board processing/handling. Once the tails are stored this way,
great care should be taken not to warm up the product during later transport and
processing. In this way, bacterial growth may be slowed, the spoilage activity and
spoilage potential of the intrinsic spoilage-associated microflora may be reduced,
and thus, shelf life might be prolonged (Gornik et al. 2011).
Nephrops norvegicus was stored at 0 °C, 5 °C and 20 °C for 10, 10 and 7 days
respectively. During the storage quality of lobster was investigated. Lobsters stored
at 0, 5 and 20 °C were rejected sensorially after 48, 72 and 96 h respectively.
Pseudomonas sp., H 2 S producing bacteria and Enterobacteriaceae caused microbial
spoilage. TVB-N was stated as a reliable quality indicator for Norway lobster
(Boziaris et al. 2011).
Juvenile Australian red claw crayfish (Cherax quadricarinatus) packed in
sealed freezer bag were stored on crushed ice (0 °C) in a cold room of 5 °C for
14 days. According to the results of the study, lipid oxidation and protein denaturation were determined in cold storage in red claw muscle. Cooking yield and
2.3 Lobsters
Pre-treatments in Processing of Lobsters
Selection
Selection is the sorting process that separates lobsters to be kept alive and discarded.
The selection process is essential for maintaining quality. Sick or dead lobsters
should be removed. Because they will die in a short time and then deteriorate. The
easiest way to separate dead and sick animals is to keep lobsters individually in
separate tanks or tank-like sections. Recently moulted lobsters should be removed
from the storage tank due to cannibalism risk. Even if these lobsters survive, their
value will be reduced as their legs and antennae will be eaten (Jacklin and
Combes 2007b).
Grading
Grading is a selection process that separates lobsters into sizes and genders to meet
market demands. In the sale of live lobsters, the buyer may have specifications for
size and gender. In this case, such requests can easily be met by the storage facilities
organizing separate tanks for certain grades (Jacklin and Combes 2007b).
Chilling of Lobsters
Crustaceans must be chilled to the point of insensitivity (unconsciousness) prior to
being killed. They should be stored in a refrigerator at approximately 5 °C, both for
food safety reasons and for the welfare of the animal. If lobsters are kept at −10 to
−18 °C for 45 min they become unconscious but do not freeze.
It is reported that in N. norvegicus, the storage temperature is the most crucial
factor affecting microbial growth, microbial activity, and spoilage potential.
Therefore, N. norvegicus tails should be stored in a cool environment immediately
after catch (even prior to ‘tailing’) and should be stored in ice (at 0 °C) as soon as
possible after on-board processing/handling. Once the tails are stored this way,
great care should be taken not to warm up the product during later transport and
processing. In this way, bacterial growth may be slowed, the spoilage activity and
spoilage potential of the intrinsic spoilage-associated microflora may be reduced,
and thus, shelf life might be prolonged (Gornik et al. 2011).
Nephrops norvegicus was stored at 0 °C, 5 °C and 20 °C for 10, 10 and 7 days
respectively. During the storage quality of lobster was investigated. Lobsters stored
at 0, 5 and 20 °C were rejected sensorially after 48, 72 and 96 h respectively.
Pseudomonas sp., H 2 S producing bacteria and Enterobacteriaceae caused microbial
spoilage. TVB-N was stated as a reliable quality indicator for Norway lobster
(Boziaris et al. 2011).
Juvenile Australian red claw crayfish (Cherax quadricarinatus) packed in
sealed freezer bag were stored on crushed ice (0 °C) in a cold room of 5 °C for
14 days. According to the results of the study, lipid oxidation and protein denaturation were determined in cold storage in red claw muscle. Cooking yield and
2.3 Lobsters