Peter,
Hope all is well with you Peter. Just a comment on storing fish (tuna &
salmon) in slush ice. It can be done successfully if done correctly by. The slurry
is usually prepared haphazardly without taking into consideration the heat of
the fish and the seawater added to make the slurry. My experiences in Chile
and S Africa have proven it's effectiveness in retarding the onset of rigor and
autolisis in the breakdown of cellular structure this preserving texture.
Regards,
Paul Dion
Paul Dion Associates, Inc.
Plymouth, MA
In a message dated 6/22/2007 12:48:47 AM Eastern Daylight Time,
phowgate@clara.co.uk writes:
> Subj: Re: Chilled Storage of Fresh Fish (tuna)
> Date: 6/22/2007 12:48:47 AM Eastern Daylight Time
> From: phowgate@clara.co.uk
> To: crt@mida-group.com, seafood@ucdavis.edu
> Sent from the Internet
>
>
>
> Chingling
>
> As Professor Labuza points out shrimp will cool within a few minutes in ice
> slurry. The time will be a little longer when stowed in flake ice, but the
> difference will not be of any technological significance. The question then
> is the balance of advantages/disadvantages between the two processes. There
> is no doubt in my mind that stowing in flake ice is to be preferred. I
> described in my previous message the disadvantages of bulk and weight and of
>
> the need to use more ice when using ice slurry and the possibility of
> layering of water and ice, but I must emphasis in the case of shrimp the
> penalty of leaching out flavourous compounds in the case of small products
> such as shrimp. I have carried out experiments on the leaching of amino
> acids, some of which are flavouring compounds themselves or flavour
> potentiators, but can be considered as representative of other flavouring
> chemicals such as nucleotides, and monitored the losses during processing.
> The loss of flavour is more pronounced in the case of headless and is severe
>
> in the case of peeled. In some cooked/peeled plants I looked at by the time
> the cooked shrimps were held in ice slurry, cooled in ice slurry after
> cooking, washed, and left standing in ice slurry between processing steps
> there was hardly any amino acids and other flavouring chemical remaining and
>
> the products were tasteless.
>
> I would recommend that shrimp be iced in flake ice rather than crushed ice
> as the large lumps in the latter can bruise the shells, which promotes
> formation of black spot, and they should be iced in shallow boxes to avoid
> compression damage, which again promotes formation of black spot. Cooling
> and stowage in ice slurry prevents this damage, but I consider that this
> benefit does not compensate for the disadvantages of this technique.
>
> Peter Howgate
>
> ----- Original Message -----
> From: "Chingling Tanco" <crt@mida-group.com>
> To: "P Howgate" <phowgate@clara.co.uk>; "Dinesh Dhammika uduwana"
> <dduduwana@hotmail.com>; <seafood@ucdavis.edu>
> Sent: Tuesday, June 19, 2007 9:00 PM
> Subject: Re: Chilled Storage of Fresh Fish (tuna)
>
>
> >Hi Peter,
> >
> >What about if you were cooling shrimp - say 15-20 grams per piece HO or
> >10-20 grams headless. Because of the size of the shrimp, heat diffusion
> >within the animal will not be much of an issue so does this make ice
> >slurry
> >more effective for cooling shrimp? What about storing shrimp overnight?
> >
> >Chingling Tanco
> >Mida Trade Manila
> >
> >
> >On 6/19/07 10:30 PM, "P Howgate" <phowgate@clara.co.uk> wrote:
> >
> >>Dinesh
> >>
> >>You need to differentiate between cooling fish in ice slurry and storing
> >>fish in ice slurry.
> >>
> >>Ice slurry, because it is in complete contact with the surface of the
> >>fish,
> >>is a better heat transfer medium than is flake ice and could be the
> >>preferred procedure for cooling large, warm fish such as tuna. However
> >>flake
> >>ice also makes good contact with the surface of the fish plus the melt
> >>water
> >>from the ice trickles over the fish making good contact with the fish.
> >>Also
> >>there comes a point in the cooling when surface heat transfer is not the
> >>limiting factor for heat loss compared with heat diffusion within the
> >>fish.
> >>Altogether there is not likely to be a big difference in rates of cooling
> >>between the 2 systems, but you would have to carry out comparative
> >>experiments to determine the size of the difference in your
> >>circumstances.
> >>Ice slurries use more ice to cool a given mass of fish than using flake
> >>ice
> >>because the water in the slurry has to be cooled down as well as the fish
> >>so
> >>is more costly than using flake. It is important when cooling fish in ice
> >>slurries that the mixture is stirred or the water phase recirculated.
> >>When
> >>the fish is added to the slurry some of the ice is melted and the
> >>container
> >>has layer of water and fish with the ice floating on top of it. If the
> >>fish
> >>has not cooled down completely this layer of fish and water will
> >>equilibrate
> >>at a temperature above 0degC and the ice floating on top will not cool it
> >>down. This does not happen with fish stowed in ice; assuming there is an
> >>adequate amount of ice all of the fish will cool down to ice temperature,
> >>(actually a little below it, around -0.2degC, to be pedantic). Chilled
> >>Seawater (CSW) systems - a slurry of ice with seawater- are often used on
> >>pelagic trawlers to cool large catches of pelagic fish, but these systems
> >>recirculate the water to ensure mixing. CSW is not the same as the
> >>refrigerated brine storage used on larger tuna boats.
> >>
> >>Though ice slurry is effective in rapidly cooling fish when used properly
> >>it
> >>is not a good medium or procedure for storing fish. Fish in ice slurry
> >>takes
> >>up more space, and weighs more than the same amount of fish in ice. These
> >>are considerations for the space required to store the fish and for
> >>transporting it. Suspension in water alters the appearance of the fish.
> >>This
> >>might not be a consideration for tuna destined for canning but is for
> >>fish
> >>going to retail sale. Depending how long the fish is stored in the ice
> >>slurry the product can lose flavour due to leaching into the water, and
> >>the
> >>fish can absorb water. This might be favourable for the economics of
> >>selling
> >>the product, but not for eating quality.
> >>
> >>The Codex advice, and other texts on storage of fish, that fish should
> >>iced
> >>in containers which allow for drainage is good advice and should be
> >>followed. Fish in ice slurries are typically held in containers with a
> >>drainage hole; just taking the bung out of the hole will allow for
> >>drainage.
> >>
> >>Peter Howgate
> >>
> >>----- Original Message -----
> >>From: "Dinesh Dhammika uduwana" <dduduwana@hotmail.com>
> >>To: <seafood@ucdavis.edu>
> >>Sent: Saturday, June 16, 2007 12:07 PM
> >>Subject: Chilled Storage of Fresh Fish (tuna)
> >>
> >>
> >>>Dear All in Seafood List,
> >>>
> >>>Looking forward for the expert opinion on what is the best way of
> >>>storage
> >>>of fresh fish either only ice (flake Ice) or in a ice slurry composites
> >>>of flake ice and water.
> >>>
> >>>code of hygienic practices for the fresh fish (Codex) says the water
> >>>from
> >>>melting ice should be drained to prevents bacteriological and chemical
> >>>contamination!
> >>>
> >>>so if we stored in a ice slurry how can we facilitate drainage in stored
> >>>in ice slurry!
> >>>
> >>>expecting expert comments soon.
> >>>
> >>>thanking you
> >>>
> >>>Dinesh Dhammika
> >>>Ensis Fisheries Factory
> >>>
> >>>_________________________________________________________________
> >>>Don't just search. Find. Check out the new MSN Search!
> >>>http://search.msn.click-url.com/go/onm00200636ave/direct/01/
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> >>>
> >>>
> >>
> >>
> >
> >
> >
> >
>
>
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This archive was generated by hypermail 2b29 : Fri Jun 22 2007 - 03:49:28 PDT