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.
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.
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 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.
This archive was generated by hypermail 2b29 : Fri Jun 29 2001 - 12:41:11 PDT