I would like to join the discussion if I may.
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Jose P. Peralta, Ph. D.
Professor/Food Engineer
Inst. of Fish Processing Technology
College of Fisheries, Univ of the Phil Visayas
5023 Miag-ao, Iloilo, Philippines
Tel (63 33) 315 8289
FX (63 33) 315 8289, 315 8353
Cell (0917) 302 1282
EMail jperalta@iloilo.net
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My Web Page
http://users.iloilo.net/jperalta/home43.html
----Charles, I have inserted a few comments into your text.
Kenneth S. Hilderbrand Jr. Seafood Processing Specialist Sea Grant Extension Program Oregon State Univ. Marine Science Center 2030 Sth Marine Science Drive Newport, Oregon 97365-5296 USA phone: 541 867-0242 fax: 541 867-0369 email: <ken.hilderbrand@hmsc.orst.edu>
-----Original Message----- From: owner-seafood@ucdavis.edu [mailto:owner-seafood@ucdavis.edu]On Behalf Of Charles Daxboeck Sent: Wednesday, June 27, 2001 2:11 PM To: seafood@ucdavis.edu Subject: Frozen tuna loins
Dear Group : We would like your advice and opinions on a product that is being proposed for export here in French Polynesia. It would be frozen tuna loins produced in a land-base facility. This would not be an IQF product such as is now produced on several of our longline tuna vessels (i.e. blast frozen, plastic wrapped loins on board the vessel - all with HACCP and EU certification for export). The proposed loins would be cut from fresh-chilled tuna, caught by longline vessels (7 - 10 day trips, storage in ice in refrigerated holds). Under a proposed HACCP plan, is it feasible (and authorized under FDA regulations) to freeze these loins (av. wt 7 - 10 kg) in a reefer set at - 18° C rather than using a blast freezer ? Storage would of course be at < -18° C thereafter. --- >The USFDA would be concerned only with the chilling time onboard the catcher vessel >and that the fish be at 4.4C or less upon delivery to the shore facility. Freezing at -18C >is not good practice but would not be a safety issue. The freezing time is a quality >issue - not a safety issue as long as the fish did not rise in temperature over 4.4C. >Freezing fish at -18C is not a good idea. In addition, you do not mention the freezing >capacity of your "reefer". Freezing rate is determined by air velocity and temperature >while freezing capacity is a measure of the system's (compressor etc.) capabilities - >usually specified in Refrigeration Tons at a specific temperature. For instance, 10 tons >of refrigeration at -18C means the ability to make 10 tons of ice in 24 hours at -18C >(about the same for fish). That works out to 2,880,00 BTU per day or 120,000 BTU's >per hour - and the system would have to have surplus capacity to account for heat >gains from freezer walls, ceiling, and floor as well fans, lights, and human activity >(such as door openings). A 10 ton system would need about 25 to 30 horse power to >run it. And even if the system had the capacity to freeze the 10 tons of fish it would be >at a slow rate and produce inferior quality product. A good blast freezer will operate at >-30 to -40C and produce a much higher quality product. --
I would like to add that containerized reefer is intended for transport and storage, with the temperature at -18 C. Thus, it should not be used other than what it is intended for.
For freezing, suggest that you use a blast freezer(with air circulation at 5 m/s) or plate freezer operating at -45 C or lower. The thermal arrest period, phase transformation from liquid to solid, should be completed within two hrs. --- If this is the case, what is the maximum time/temperature delay allowed to get the product from ambient to final target temperature of - 18° C ? -- >What is the ambient temperature? The fish should be received from the boat at 4.4C or >less. --
Prior to freezing, it is suggested to remove the sensible heat by immersion in ice water until the fish temp drops to about 0 C. --- Given that this is not an IQF product, and that the fresh product shelf life (depending on species and quality of course) is at most 2 weeks from time of capture, can it still be considered safe to freeze within the safe "best used before" date, or is there a time limit after harvest (from time of catch - 5 days are recommended limit for vacuum packed or processed products) for which such processing can be allowed ? -- >A "best used before" date is a quality issue - not one of safety. The product should >never be allowed to warm to over 4.4C. -- Are these tuna loins considered a processed product or a simple transformed product ? -- >Any manipulation of the product once it is on shore would be considered processing >requiring a Hazard Analysis - and for tuna a HACCP plan always. --
In seafoods, there has been no distinction between what is minimally processed and processed, unlike in the processing of fruits and vegetables. The result of any manipulation of the fish is considered a processed product.
In my opinion, tuna loin processing is under minimally processed products category. ---
In any case, I imagine we will have to perform histamine analyses on a few lots before any export can be envisaged, since this is the identified danger, through possible time/temperature abuse. -- >You can use histamine analyses to verify that your CCPs (receiving and storage >temperatures) are adequate to control histamine formation. -- For labeling, other than not stating IQF, would there need to be special mention for "frozen in a land-based facility" ? >NO. -- What would be the estimated (legal ?) time limit or "use by" date once the product is thawed and sold ? >A "use by" date, if placed on a label, should be determined by testing and would >depend on product quality. This fish should never be exposed to temperatures over >4.4C. -- I trust I have not burdened everyone, but I do appreciate your collective wisdom and input. >I have a colleague (currently out of the office) who may have additional references for >your edification and a computer model which would estimate freezing rates. Thanking you all in advance. Charles Daxboeck.
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