Date: Fri, 26 May 2000 14:24:08 -0700 (PDT)
From: Faye Dong <fdong@fish.washington.edu>
To: Seafood listserve <seafood@ucdavis.edu>
This is in response to Robert Blair's inquiry about the time/temperature
treatment to kill parasites in salmon. We are presenting a paper at the
IFT annual meeting in Dallas on Monday afternoon (6/12) in the Seafood
poster session ["Survival of Anisakis simplex in Arrowtooth flounder
(Atheresthes stomia) during freezing processing" by Faye M. Dong, My N.
Ton, Ann M. Adams, Alan P. MacKenzie, and Marleen M. Wekell], so please
come by if you are interested and will be at this meeting.
The abstract can be viewed at:
http://ift.confex.com/ift/2000/techprogram/paper_4473.htm
We tested 4 freezer temperatures (-15C, -20C, -30C, and -40C), and all of
them were non-blast models. The minimum total times that resulted in
total kill of Anisakis simplex in arrowtooth flounder fillets were:
-15C 96 hours
-20C 60 hours
-30C 12 hours
-40C 9 hours
According to our data, if a fish is frozen to a core temperature of -20C
and held in storage for 24 hrs, it will not always result in total kill of
the nematodes. In our non-blast -20C freezer, we measured the time it
took for the middle of the fillet to reach -20C (9.5 hr). Taking that
into account, our data showed that holding fillets for either 26.5 hr or
38.5 hr at a core temperature of -20C resulted in 11-51% survival of the
worms!
We realize that blast freezers will result in much faster freezing rates
than non-blast models. However, at -20C, which is close to the
temperature of home freezer compartments, it appears that in a non-blast
freezer, 60 hrs is a minimum (with no added safety factor) or 50.5 hrs
after the fish reaches a core temperature of -20C.
Faye Dong
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Faye M. Dong
University of Washington
School of Fisheries
Marine Studies Building, Room 207
3707 Brooklyn Ave., NE
Seattle, WA. 98105-6715
Phone: (206) 543-0603
Fax: (206) 543-1417
Campus box: 355680
E-mail: fdong@fish.washington.edu
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NOTE: links to the various SEAFOOD TOPICS plus IFT ANNUAL MEETING
registration information is available on the web at:
http://www.ift.org/divisions/seafood/00techpro.html
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