hazard. Dose–response models which relate the number of micro-
organisms ingested and the likelihood and severity of clinical
illness are a valuable tool, but development of such models for
foodborne pathogens is still in its early stages. There are very
limited scientific data available compared with chemical hazards
and there are additional difficulties arising from the complexity of
micro-organisms. Some dose–response data have been obtained
from studies conducted with volunteers, but these can be a crude
model of the real situation since the volunteers all tend to be
healthy adults. Other complicating factors can be the wide var-
iation in virulence between different strains of the same organism,
variation of virulence with the organism’s physiological state and
the important role played by the food vehicle in modulating the
ability of the organism to cause infection. Alternative approaches
have used information from disease outbreaks to generate more
realistic dose–response models, but this is an area where consid-
erable developments are likely over the next few years.
(4)Risk characterization integrates the results from the previous
three stages to give an estimate, including attendant uncertain-
ties, of the probability and severity of illness in a given popula-
tion. The accuracy of the estimate can be assessed by comparison
with independent epidemiological data where available.Risk management (Figure 11.13) is the process of deciding, in collabo-
ration with risk assessors, which risk assessments should be undertaken
and then weighing policy alternatives to accept, minimize or reduce
assessed risks. Risk managers have to decide what level of risk is
acceptable (zero risk is an unachievable objective), assess the costs and
benefits of different control options and if required select and implement
appropriate controls, including regulatory measures. Management also
includes the subsequent evaluation of the effectiveness of the measures
taken and their review, if necessary.
The final component in risk analysis is risk communication – the
interactive exchange of information and opinions between risk assessors,
risk managers, consumers and other interested parties. This is an integral
part of risk analysis and has a number of goals including the promotion
of awareness, understanding, consistency and transparency.
Following an assessment of risk and its management options, it may
be possible to define a food safety objective – a statement of the
frequency or the maximum concentration of a microbiological hazard
in a food that is considered to give an acceptable level of consumer
protection. This can then be used by the food industry as a goal to
be delivered through the application of good hygienic practices and
HACCP. With this we reach something of a high point in the
438 Controlling the Microbiological Quality of Foods