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
