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
