Can Paul Dion expand on his message. What is a 'blast boat' and what is involved in a 'defrost cycle'. Were the tuna in the ship's cold store? How was the temperature of the product measured? The temperature range he quotes is quite extraordinary for the temperature fluctuation of product that would be expected in the defrost cycle of a cold store.
While I'm writing, let me go back to the original message. Enrique is quite correct of course; codes of practice, international transport agreements, regulations and such like recommend or specify the maximum temperature for storage of frozen foods. I am not aware of any regulations or similar relating to minimum temperatures of storage, though I am aware of quality assurance specifications of some fish processing companies that requires storage at lower temperatures, usually below -25 degC. Manuals of handling of frozen fish such as FAO Fisheries Technical Paper 340, Freezing and Refrigerated Storage in Fisheries, usually recommend that frozen fishery products be stored at -30 degC. The good quality storage life of fishery products, including shrimp, is around 3 months at -18 degC, which bearing in mind inevitable delays in the distribution chain is not long enough to ensure a good quality product to the consumer.
Peter Howgate
----- Original Message -----
From: PDIONPDA@aol.com
To: jn@dfu.min.dk
Cc: seafood@ucdavis.edu
Sent: Friday, November 26, 2004 2:49 AM
Subject: Re: frozen product core temp
Jette,
How does the fluctuation of temperatures between -20C & -30C effect quality? I have seen frozen tuna fluctuate onboard from -20F to 0F during defrost cycles on blast boats. Dockside buyers and processors do not seem to care or maybe it is just that they are unaware of these temperatrure swings during onboard holding, unloading and transport.
Paul Dion
Paul Dion Associates, Inc.
Plymouth, MA
USA
This archive was generated by hypermail 2b29 : Fri Nov 26 2004 - 02:01:37 PST