Dear colleagues,
Thank you for your messages. I do not think I have the right answers
for all the questions you put forward, however, since I was involved with
this discussion I will try to give my opinion on the three main areas I have
received messages.
(i) I do not think it could exist an "ideal" insulated box or crate
suitable for any occasion. I think that it depends on the whole chilling and
handling system you have in mind, and sometimes in the capital you dispose
for your objective. For instance if your idea is to move/ store middle sized
fish in an industrial environment with chilled hulls (on board) and chilled
rooms after landing (4-5 degree C), then a boxing (or crate) system with the
characteristics required by Mr Peralta could be utilised, even under
tropical and semi-tropical conditions. There are a number of good
boxes-crates with such characteristics in the market.
However if the box/ crate will (or could be) be delayed at a certain point
in the chain (e.g. on the deck, on landing, when transported to the plant o
market, in the market, etc.) then an insulated container may be necessary.
This will depend on the delays involved (I assume a tropical semi-tropical
condition). In this case some characteristics like the possibility to stack
or nest could not be there. The reason is that the main necessary
characteristic of insulated containers is to be (thermally) insulated.
Other characteristics could change, for instance most of insulated
containers can be drained. However, drainage is in general not allowed
during storage because it will increase ice melting rate (temperature is
considered the chief parameter in this case, and it is preferred to have
fish near 0 degree C than to have fish just wet and not submerged in water).
As happens with the design of simple boxes for a boxing system, to design
insulated fish container presents a number of alternatives and to optimise
one will means to sub-optimise the other and vice-versa.
(ii) Regarding use of ice in developed countries I agree that even though
the cost of ice could be low it does not means that it should not be taken
into account. Insulated containers to keep fish with limited amount of ice
are utilised for instance in Denmark and Japan. In some developed countries,
particularly in the Scandinavian countries, there is a move towards clean
(and lean) production, this means to the reduction of all material (and
energy) that could be reduced.
The reduction of ice for instance means a reduction in energy consumed and
in effluents to treat, it also means a reduction in storage volume needed
and in some cases (depending on design) an increase in productivity.
Increase in productivity (and the consequent saving) due to lower volumes to
handle or dispose of or clean (very often manually) could in developed
countries represents a much large figure than just the cost of ice saved.
My advice is to look into ice cost and use even if you are running and
industrial system utilising cheap ice.
(iii) It is true that a lot of information is needed to design a chilled
fish chain, however, it is not a prohibitive amount of information
(definitely not the amount of information needed to put a man in the Moon).
Most of the ice plant makers have standards procedures to estimate the size
of ice plant you may need for a given purpose. However, you may want to
check and know by yourself. In this sense it is crucial to know distances
and time (of storage, transport, etc) and interact with the thermal
characteristics of your possible container. It is necessary to know if ice
should be carried to the point you are getting the fish or not , etc. Some
thermal test of containers in actual operations may be necessary. We should
not forget that combined solutions can exist, for instance refrigeration
equipment (mounted in an insulated truck) combined with a reduced amount of
ice.
Limitations could be in the necessary insulation (too big and heavy) or in
the cost of the possible insulated container or system, but again this has
to be analysed case by case, there is no possibility to give general rules..
I know that processes of this type have been conducted in the past by trial
and error, however, it may lead to a wastage of money. If there is a
possibility to estimate or calculate it, it is better to do so, and then add
a reasonable safety factor (as in any estimation).
Hector M. Lupin
Fish Utilisation and Marketing Service (FIIU)
Fish safety and quality assurance
Tel.: (39)(06)570-56459
Fax. (39)(06)570-55188
e-mail: hector.lupin@fao.org <mailto:hector.lupin@fao.org>
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