No parasites of health concern? Really? I seem to remember reading in
Desowitz's book (New Guinea Tapeworms and Jewish Grandmothers) about
someone getting a rather nasty (round?) worm from eating raw tuna. Pete
Peter A. Nelson
Marine Advisor
California Sea Grant
Adjunct Professor
Dept Fish. Biol., Humboldt State University
2 Commercial Street, Suite 4
Eureka, California 95501
Tel 707.443.8369
Fax 707.445.3901
panelson@ucdavis.edu
On Jan 10, 2007, at 10:36 AM, John Kaneko wrote:
> Janani,
>
> What species of tuna are you referring to as "red tuna". Do you
> mean yellowfin, bigeye, or bluefin?
>
> These species of tuna are commonly eaten raw as sashimi. They do
> not contain parasites of public health concern in the edible
> muscle. Therefore freezing these fish prior to raw consumption is
> not necessary.
>
> Freezing temperatures for tuna for other reasons such as
> transportation, storage, etc. depends on the intended end use. For
> canning raw material, freezer temperatures need not be very low.
> The raw frozen tuna oxidizes and turns brown. But after cooking and
> canning, the color of the raw muscle is not an issue.
>
> To retain the natural red color and muscle clarity required for the
> sashimi market, freezing must be done at sea immediately and at
> ultra low temperatures (ULT). This requires specialized equipment.
> ULT frozen tuna is common in Japan because of the distance the fish
> must travel from the fishing grounds to the market and not because
> of a parasite food safety risk.
>
> Frozen tuna treated with carbon monoxide does not need to be frozen
> or shipped at ultra low temperatures because the carbon monoxide
> prevents the natural oxidation that would otherwise result in the
> normal color change from red to brown. Carbon monoxide treated tuna
> retains its unnatural red color without requiring ULT freezer
> temperatures.
>
> Aloha,
>
> John Kaneko MS, DVM
> PacMar Inc.
> Honolulu, Hawaii
> ----- Original Message -----
> From: Janani Tulasendrapuram
> To: seafood@ucdavis.edu
> Sent: Wednesday, January 10, 2007 6:09 AM
> Subject: Parasites in Red Tuna
>
> Good morning,
> This is regarding parasites in Red Tuna. Is there a published
> lethality table that deals with temperatures above -20C? FDA says
> -35C for 15 hours is a good as -20C for 7 days. But what if you
> could only guarantee -10C in the transportation chain? How many
> days at -10C would you need?
> I would appreciate it, if anyone can pass along any information
> regarding the above.
>
> Thanks and have a nice day!
>
>
> -Janani Tulasendrapuram
>
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