Day 107 - 24 Mar 95 - Page 73


     
     1        A.  It is probably anything from about 60 degrees upwards.
     2
     3   Q.   For how long?
     4        A.  Ah, now that is the key.  I have not seen very detailed
     5        studies and I do not know that they have been done.  Let me
     6        go back to salmonella, and it is a good indication because
     7        the two are assumed to have similar characteristics,
     8        although I believe E.coli is actually slightly more
     9        sensitive.
    10
    11   Q.   I think that is what you were telling us, yes?
    12        A.  Yes.  Salmonella target in an optimum environment is,
    13        say, 63 degrees for half an hour, or if you bring it up to
    14        72 degrees, you are talking about 15 seconds.
    15
    16   Q.   If I can just remind you in appendix -- there is no need to
    17        look at it because I am not going to cheat and read out
    18        anything wrong -- A of your paper in 1989 you say this:
    19         "Salmonella has two general characteristics which exist in
    20        its control.  Firstly, it is relatively easy to kill.  A
    21        temperature of 63 degrees for half an hour or 72 degrees
    22        Centigrade for 15 seconds will destroy the organism in
    23        milk.  Core temperatures of 70 degrees Centigrade are
    24        recommended in other foods to ensure salmonella
    25        destruction"?
    26        A.  Yes.
    27
    28   Q.   I am not disagreeing with that for one moment -- on the
    29        contrary.  I think what you are telling us then is that
    30        somewhat lower temperatures than that may be effective to
    31        destroy E.coli 0157?
    32        A.  Yes, in fact, please bear in mind these temperatures
    33        I have cited are in milk.  Now, one finds that heat
    34        tolerance actually decreases with medium -----
    35
    36   Q.   Sorry, that is not quite right.  I am sorry for not asking
    37        you to look at it.  You say:  "Core temperatures of 70
    38        degrees Centigrade are recommended in other foods"?
    39        A.  Yes, quite so.
    40
    41   Q.   So, if 70 is the right temperature for whatever the given
    42        period may be for the destruction of salmonella, and E.coli
    43        0157 is a slightly more fragile organism than that, a lower
    44        temperature will do?
    45        A.  Yes, under certain circumstances.
    46
    47   MR. RAMPTON:  My Lord, I am wondering whether, in fact -- having
    48        said that I might not finish this afternoon -- if I had
    49        your Lordship's -- I know it is Friday -- leave to go a
    50        little bit past time one might, in fact, not make Mr. North 
    51        come back on this particular part of the cross-examination; 
    52        whether that matters, I do not know. 
    53
    54   MR. JUSTICE BELL:  No, if you can complete your
    55        cross-examination, subject to the same comment which I made
    56        to Ms. Steel, that if Mr. North is going to come back
    57        anyway, I am not going to start saying:  "You had an
    58        opportunity to ask that last time; this is not something
    59        new".  How long do you think you might be?
    60

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