Re: pH of sushi rice

From: Robert A. LaBudde (ral@lcfltd.com)
Date: Thu Apr 27 2000 - 10:52:58 PDT

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    At 08:42 AM 4/27/00 -0700, Mika wrote:
    >To: Seafood HACCP Mailing List
    >
    > Sushi rice is vinegared and stored at a room
    >temperature. A health department inspector came to a
    >Japanese sushi restaurant, and he said that keeping
    >sushi rice at a room temperature was a violation and
    >the rice was thrown away. However, the sushi rice was
    >made twice a day for lunch and dinner at this
    >restaurant, and when the rice pH was 4.6 or below, it
    >is not a hazardous food. The owner explained about
    >sushi rice pH, but the inspector asked him to bring
    >the rice to a laboratory and check the pH. At the
    >laboratory, conducting a challenge test about
    >sushi rice costs $2000-$5000 for various pH levels and
    >storage temperatures. OR a 2-hr seminar costs $700 to
    >teach the Japanese owners how to measure rice pH. A
    >material fee of $30 per person will also be charged to
    >measure their own rice.
    > I think it's very expensive and there are other
    >less expensive solutions. I propose to buy the pH
    >kits and tell the owners how to measure their pH. I
    >will provide a cost estimate shortly. Does someone
    >have any good ideas?

    If sushi rice is just rice, water and vinegar, it has a predictable pH. A
    simple experiment would prove this. Then the CCP would be the % vinegar
    addition in the make-up, plus the maximum hold time.

    Salmonella can grow at this pH, but only slowly. Bacillus (a key rice
    hazard) won't grow below pH=5 (it dies slowly) and neither will
    Clostridria. Staphylococcus will not generate toxin below pH=5.3 or so.

    If you can't get help otherwise, email me privately and I'll see if I can
    run a simple validation study for you on pH.

    ================================================================
    Robert A. LaBudde, PhD, PAS, Dpl. ACAFS e-mail: ral@lcfltd.com
    Least Cost Formulations, Ltd. URL: http://lcfltd.com/
    824 Timberlake Drive Tel: 757-467-0954
    Virginia Beach, VA 23464-3239 Fax: 757-467-2947

    "Vere scire est per causae scire"
    ================================================================



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