Day 106 - 23 Mar 95 - Page 54


     
     1        pathogen specifically; it is only 0157 in the context of
     2        this industry which is regarded as the pathogen.  So I take
     3        it in respect of perfringens, staphylococci and,
     4        particularly, salmonella.  In a search for 0157, bearing in
     5        mind that it is so low as far as we know in incidence, you
     6        would probably have to take an enormous number of
     7        samples -----
     8
     9   Q.   If E.coli written there were shorthand for E.coli 0157: H,
    10        if it was, then your comment would apply to that?
    11        A.  It would apply, yes, absolutely.
    12
    13   Q.   But you say you do not think it can be because otherwise
    14        you would not have a 50 in the N column.
    15
    16   MR. MORRIS:  I cannot remember what the evidence given in that
    17        was.
    18
    19   MR. JUSTICE BELL:  Leave that on one side.  Of course,
    20        Mr. Rampton has to ask questions yet.  All I am doing at
    21        the moment, Mr. Morris, is making sure I understand what
    22        the effect of Mr. North's evidence is.  Yes.  I understand
    23        what you are saying now, Mr. North.
    24
    25   THE WITNESS:  Of course, the higher the predicted level the less
    26        number of samples you take, so you could not necessarily
    27        apply those criticisms to the Sun Valley operation where,
    28        with a 25 per cent at whatever level it was, at whatever
    29        stage it a was, you would have to take relatively few
    30        samples to detect salmonella.  It was interesting they did
    31        not take salmonella samples there routinely for that
    32        specific purpose for McDonald's purposes, but I know from
    33        discussions that they took their own samples routinely.
    34
    35   Q.   It might be said, I do not know, if you are, nevertheless,
    36        doing these tests day in day out, if E.coli or any of the
    37        other three at the bottom of that page are coming through
    38        with any regularity, even 0.1 per cent of cases over a
    39        period of weeks or months, you are going to hit one sooner
    40        or later and that might then cause you to revise your
    41        tests.  What do you say about that?
    42        A.  There has been a very spirited discussion on sampling
    43        theory in relation to the National Lottery.  It is an
    44        indirect but quick way of answering your question.  Your
    45        odds of finding it do not improve.
    46
    47   Q.   I know, you have exactly the same chance tomorrow as you
    48        have today.
    49        A.  Yes, and it is the same thing here.  If your chances
    50        are very, very low, the fact that you repeat a procedure 
    51        with a very low probability of finding something, does not 
    52        improve statistically your chance of finding it. 
    53
    54   MR. MORRIS:  As I understand the situation, each consignment
    55        that arrives at McKey's, not each combo bin but each
    56        consignment, one of the bins will be tested, I do not know
    57        how many consignments they get a day, I cannot remember
    58        now, it was one of the things we were looking for in the
    59        documents -- well, we have an indication that they may get
    60        17 consignments a day of 12th January 1994 -- if there is

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