Influence o f the storage m ethod on the q u ality o f Norway lobster
(Nephrops norvegicus)
Bekaert Karen, Daphné Deloof, Lisa Devriese, Sara Maes, Kevin Vanhalst, D irk Verhaeghe
and Johan Robbens
Anim al Sciences Unit - A quatic Environm ent and Quality, Institute o f A g ric u ltu ra l and Fisheries
Research (ILVO), A nkerstraat 1, 8400 Oostende, Belgium
E-mail: karen.bekaert@ ilvo.vlaanderen.be
Norway lobster (Nephrops norvegicus), as many o the r seafood products, is a very perishable food
item. Therefore, o ptim al handling and storage practices, at sea and ashore, are essential
com ponents in the q u a lity m anagem ent to realize a m axim um return on national and international
markets. In Ireland, Norway lobster is stored on board in a stacked way: a layer o f ice is placed in a
box, follow ed by Norway lobsters, a bag w ith fine meshes and on to p again a layer o f ice. This
m ethod has the advantage th a t the fine mesh protection m inim izes damage to limbs as it provides
a protective cover when ice is removed during sorting and also helps prevent bleaching. A t ILVO, an
e xperim ent was conducted to te st which influence th is m ethod has on the q u a lity o f Norway lobster
and its u tility fo r Belgian fisherm en was evaluated as an alternative to the tra d itio n a l icing o f
Norway lobster (ice between the Norway lobsters). The difference between the tw o storage m ethods
was assessed by using m icrobiological (Total Viable C ount on Marine Agar and Iron agar, H2Sproducing bacteria, Pseudomonas spp.), sensory (Q uality Index Method) and chemical parameters
(Total Volatile basic N itrogen) during a 14-day storage experim ent.
The firs t 5 days o f the experim ent, there was no difference in sensory, chem ical and m icrobiological
param eters between the storage m ethods. From day 6 o f storage, a sign ifican t higher am ount o f
bacteria was observed on the Norway lobster stored in the Irish way fo r to ta l viable count on Marine
Agar and H2S-producing spoilage bacteria. However, no sig n ifica n t difference could be observed fo r
the o the r m icrobiological param eters or fo r the sensory and chem ical parameters. The am ount o f
Total Volatile Basic Nitrogen started to increase from day 7 o f storage. This coincided w ith the
grow th o f Pseudomonas spp., which are known spoilage bacteria o f Norway lobster (Boziaris e t al.,
2011). The direct contact w ith ice o f the tra d itio n a l Belgian storage m ethod clearly lim its grow th o f
m icroorganism s. On the o the r hand, great variations in results between individuals, probably due to
th e ir position in the boxes, can explain th a t the other param eters did not d iffe r significantly. To
conclude, fo r short fish in g trip s as is the case in Ireland, the use o f the meshed bag fo r storage o f
the Norway lobster cannot be considered as disadvantageous. However, th is storage m ethod is not
applicable to the Belgian situation due to longer sea trips. Therefore, we advise the fisherm en to
continue storing the Norway lobsters in the tra d itio n a l way.
References
Boziaris I.S., A. Kordila, and C. N eofitou. 2011. M icrobial spoilage analysis and its effect on chemical
changes and shelf-life o f Norway lobster (Nephrops norvegicus) stored in air at various
tem peratures. International Journal o f Food Science and T echnology 46(4):887-895.
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