Examination of Witnesses (Questions 80
- 99)
WEDNESDAY 29 NOVEMBER 2000
PROFESSOR SIR
JOHN KREBS
AND MR
GEOFFREY PODGER
80. We have to trust the French?
(Professor Sir John Krebs) There has to be an element
of trust in it, absolutely.
81. Do we?
(Professor Sir John Krebs) Referring back to a comment
that I made earlier, when we asked at the beginning of the Agency,
looking not at BSE controls but at meat inspection more generally
in abattoir performance, where do we come in the European league
table, we came about half way down near the French, so the question
could be asked about us. Is there any reason to trust the Brits?
82. You also said in respect of BSE our controls
are the most effective and we are very high on the league there.
(Professor Sir John Krebs) I said I do not know because
we do not have the data, but I would imagine we would do well
because we have been through a longer and more painful experience
than other countries. It is quite right, given the experience
we have had, that we should have tighter controls than any other
country. We still have more BSE cases this year than any other
country in Europe by a long way. As to whether the controls in
other countries are inadequate given their level of BSE, that
is up to the Commission to check and that is why I am very pleased
that the Commission is going in to check a number of Member States
as we speak.
83. You also said that you were not sure at
this stage whether the incidence in France is just a step up to
a new level or whether it is the beginning of an epidemic. In
that state of uncertainty, would not a sensible precautionary
principle be to ban the stuff?
(Professor Sir John Krebs) It depends on what you
think a precautionary principle implies. To me, it implies working
with the knowledge you have, recognising the uncertainties and
taking proportionate action. There is an element of judgment there
at the end of the day as to what constitutes proportionate action
but in my view, given the knowledge we have now and the uncertainty
surrounding that knowledge, we are not in a position to recommend
that on risk grounds. We could do it on nationalistic grounds,
but not on human health risk grounds.
84. You are saying we do not know whether they
are enforcing it effectively. We do not know whether it is the
outbreak of an epidemic, but we should still make a judgment that
we do not ban it.
(Professor Sir John Krebs) We make a judgment on the
knowledge we have now and we are prepared to change our judgment
if the knowledge changes. One important piece of information will
be the report of the European inspection team when they have been
to France.
85. You are not saying to them, "Remove
the ban on our beef", because you are not going to touch
the subject.
(Professor Sir John Krebs) That is not our responsibility.
86. But you are saying, "Our controls are
the most effective in the world and you have a lot to learn from
us, but we are not going to ban your beef and we think your controls
should be improved." What lessons would you learn from that
if you were a French bureaucrat?
(Professor Sir John Krebs) I am not a French bureaucrat
and I do not want to necessarily think about what lessons French
bureaucrats learn, but I have said clearly that the scientific
case for the French ban on United Kingdom beef in our opinion
is non-existent. It is not a scientifically based argument. I
would not like to put us in the position on my recommendation
of the French saying, "Well, the United Kingdom has banned
our beef but it is not a scientifically based argument."
My job is to provide a rigorous assessment and risk management
advice to government. If people want to base their argument on
other grounds, that is their business, not mine.
87. In general, how does the FSA calculate risks?
How do you allow for uncertainty?
(Professor Sir John Krebs) We rely on expert advice
in calculating risk. Usually, if you have uncertainty, you take
a number of scenarios. You might take a best case scenario if
you are an optimist and a worst case scenario as a pessimist and
then somewhere in between. If you wanted to estimate the risks
associated with meat being imported from France, for example,
you could consider what would be the risk under the assumption
that all the rules are being breached. What would be the risk
under the assumption that all the rules were being fully applied?
What would be the risk under the assumption that the rules are
somewhat half way or some proportion in between? That is in general
how one deals with risk assessment under uncertainty. What is
very important is, when you do that kind of risk assessment, you
do not get seduced by precise numbers and quantitative detail.
If I did that kind of risk assessment and I came back to you and
said, "The number of 0.00132", you should say, "Rubbish.
Give me an answer to an order of magnitude. Is it of comparable
order of magnitude to the risk from United Kingdom beef or is
it a different order of magnitude? What is your uncertainty in
that estimate?" We have to be willing to accept that we cannot
estimate things precisely and quantitatively. We can talk about
orders of magnitude and relative assessments for different countries.
88. And publish the parameters.
(Professor Sir John Krebs) Yes, one has to make it
completely clear.
89. Do you differentiate between risks according
to exposure of abattoir workers and consumers or farmers? Do you
make distinctions here?
(Professor Sir John Krebs) Occupational risks?
90. Yes.
(Mr Podger) In work carried out, if it is thought
there might be a particular risk to a particular sector, you would.
We normally start from general population risk assessment. One
would always ask the question: is there a particular issue for
vulnerable groups, which very often there is. Very often, the
young, the elderly, pregnant women, people who are immuno-suppressed,
for example, in a whole series of areas the risk to them is greater.
One of the issues that does arise from time to time is where it
appears that a particular group are susceptible and it is very
important obviously not just to do a general population risk assessment
in which they may become completely hidden, which is obviously
your point. One does try to do that and the advisory committees
do.
(Professor Sir John Krebs) For instance, the risk
assessment associated with pesticide levels takes into account
the most vulnerable groups as one of the multipliers in calculating
the acceptable exposure levels.
91. But you do not publish risks between whether
the meat is sourced from different countries. You stay out of
that.
(Professor Sir John Krebs) We have not to this stage
published a formal risk assessment of meat from different countries
within the European Union, although we are looking at that area
and there is work going on in the research community, trying to
develop models of risk assessment.
92. Would that not be a sensible solution, to
publish the risks from each country and label that by country
of origin?
(Professor Sir John Krebs) Bearing in mind what we
have just said about risk assessment under uncertainty, these
risk assessments will be only within very wide bounds. I do not
think you would want to put a number on it and say, "This
is risk category one, two or three", because there will be
a lot of assumptions going into that risk assessment. It is helpful
to inform policy judgments but I am not sure that at this stage
we have the knowledge that would help consumers to choose. Consumers
would probably quite rightly say to us, "If product A has
an appreciably greater risk because it comes from country X than
product B which comes from here, why are you allowing it to be
sold anyway?" I do not think we can substitute consumer choice
for risk management.
93. The Phillips report is full of lessons for
everybody. I wondered what you thought the lessons for scientists
are, whether they are speak out like Professor Lacey, lose your
job, your laboratory and your funding or shut up like the chief
medical officer and the chief scientific officer.
(Professor Sir John Krebs) I am not going to support
the view that the CMO and the CSA shut up. The recently retired
CSA, Sir Robert May, spoke out very forcefully on key issues.
94. Is there a lesson in favour of speaking
out?
(Professor Sir John Krebs) Yes, but in general the
lesson from Phillips for the scientific community is rather analogous
to the lesson that Geoffrey Podger referred to for governments.
It is to not get entrenched into defending a position that you
took up at the start. Be willing to listen to the challengers.
Be willing to change your mind as new evidence comes along. Scientists
are human like everybody else and they sometimes get stuck in
entrenched positions and resist all the contrary evidence because
it disagrees with their favourite hypothesis. That would be a
general lesson to everybody involved from the scientists through
to the politicians that we should be willing to change our minds
in the light of new evidence if the evidence demands that we come
to a different view.
Chairman
95. It is legitimate, is it, always to ask the
challengers if their own opinions can be proven or have the same
degree of certainty as those defending the proposition?
(Professor Sir John Krebs) Absolutely. A difficult
area is that some fringe people in the scientific community are
just that. They are there as irritants but they have no basis
for their arguments. Other people are actually serious minority
view holders and it is a judgment to distinguish and pick out
the ones who have a serious point to make. Your proposal to ask
them what the basis of their argument is is an important way of
achieving that.
Mr Jack
96. One of the things that has intrigued me
in recent times is the use of the phrase "BSE infected meat".
The reason I ask this question is because I think it is relevant
to the public perception of risk. Am I right in saying that so
far, as far as the actual beef tissue that we eat as meat is concerned,
no infectivity has been found in it in the United Kingdom?
(Professor Sir John Krebs) The tests that have been
done by grinding up bits of cows with BSE—brain, guts, limbs
etc.,—and injecting those into these mice to see whether
the mice develop BSE did not show any infectivity in the meat
that we eat. The infectivity is found in the areas that are now
treated as specified risk material: the brain, the spinal cord,
the dorsal root ganglion.
97. If we are to develop a proper understanding
of where risk comes, which would be from the consumption by human
beings of the bits that we have identified with infectivity in
them, do we need to change the language that we use and, if so,
what role are you playing to get people to focus on where the
real risk is?
(Professor Sir John Krebs) It is an important point.
It is quite a sophisticated argument to get across. What we say
in simple terms is that the two hurdles that meat or meat products
coming into the food chain have to cross are, first, the cattle
have to be under 30 months; secondly, the bits of the body that
might contain infectivity have to be taken away and destroyed.
Those two hurdles ensure that for you, the consumer, the meat
and meat products you eat are minimal risk. We cannot say there
is zero risk because bits of stuff could get stuck to the carcass
or there may still be some surprises for science as to where infectivity
lies.
98. That takes me back to something you touched
on earlier, which was the question of the systems that are being
used to monitor French imports and possibly others. There were
calls I think in The Daily Telegraph that your Agency should
give greater clarification on the way in which the assessment
was to be done, particularly in the context of animals over 30
months. You said earlier that this was a documentary check and
that was the most you could hope for. Are you satisfied that meat
entering the United Kingdom from not just France but also other
parts of the European Union where, albeit minimal, incidents of
BSE have been discovered, are robust in enabling you if necessary
to have full traceability to source a particular animal if you
either wanted to run a spot check or there was doubt about the
authenticity of the evidence on the piece of paper.
(Professor Sir John Krebs) This is partly a matter
for the food manufacturers and retailers. Geoffrey has had quite
a lot of conversations with the major retailers on their authentication
and traceability systems.
(Mr Podger) Generally speaking, the major retailers
and probably the major meat processors would say they do have
traceability on their carcass meat. What we do not have traceability
on are meat products which are already made up as meat products
before they arrive in this country, for the obvious reason. I
think my experience of the food industry is that they find those
very difficult to trace back.
99. In that context, because you rightly counselled
us that it was the incorporation of potentially infected tissue
material in which there could be a risk, what is the scientific
test situation? Can you take, for example, pâté and
establish whether it contains any infectivity? Is there a test
to do that?
(Professor Sir John Krebs) There are two stages. Can
you test the pâté or whether it has specified risk
material in it, neural tissue or tissue from beef. There are tests
for whether it contains beef and people are developing tests for
the presence of neural tissue, specific markers for neural tissue.
The second kind of question is can you test whether the infective
prion is in a particular batch of meat products. The answer is
yes, you could because you could take the pâté and
inject it into animals. Usually they use the mice that I keep
on referring to as the test animals. You could in principle and
indeed in practice test whether a particular meat product contained
infectivity, but I suspect the more important thing for health
protection is to check that the meat product does not contain
specified risk material because that would show that enforcement
was being carried out properly.
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