Commission(see below),uses a scheme verysimilarto this general four-step
model.
Because part of a risk assessmentis the estimationof probabilities,it relies
heavily on statistics. Quantitativerisk assessment in almosteveryfieldneeds
largeamountsof dataand/orstatistical modelcalculations.The development
in the past decadesof powerful computers that analysestatisticaldataand
perform modelcalculationshas boosted the use of risk assessmentstudiesin
all fields.
20.1.1 Historical evolution of riskassessment in foodhygiene
Althoughriskassessment has beenused in variousareassincethe earliest
history, its applicationto ensurehygienic foodproduction is relativelynew.This
is mainlybecause knowledgeon foodhygienewas verylimiteduntilthe first
half of the 20thcentury(Notermanset al., 2002).
Evenlongbeforethe underlyingcausesof foodbornediseases were known,
therewererational approachesto the controlof foodsafety.Experience and trial
and errorresultedin rulesfor foodhygiene that wereoftenexpressed as religious
taboos. A well-knownexample is the ban on eatingporkin the Jewish and
Muslim religions(Tannahill, 1973).In the absence of knowledgeaboutthe
causes of foodborne diseases, legislatorsusedan approach similarto religious
taboos. This approach is also known as the prohibitionprinciple: it was
prohibitedto produce or consume certaintypes of foodafterit was realisedthat
a specific foodcould causeillnessor death.As an example, in the MiddleAges,
in the Swisscities of Zurichand Basel,it was forbiddento sell fish that had been
left overfromthe day before(Notermanset al., 2002).Evennowadays,although
knowledgeon foodsafety has increased dramatically,legislatorssometimes use
an approach comparable to the prohibition principle, now called the
precautionary principle.Thisapproach impliesthat policyshoulderr on the
side of caution when scientificevidenceon the foodsafetyof new technologies
is incomplete, so that the risk to the consumeris minimised.The precautionary
principlewasfor example invoked in the CartagenaProtocolon Biosafety
(Anon,2000).The documentstatesthat evenwhen thereis a lackof scientific
evidencethat products produced throughbiotechnologyare likelyto causeharm,
a countrycan ban the import of thoseproducts.
The first half of the 20thcentury saw a vast increasein knowledgeon how
heattreatmentscan be usedto destroy microorganisms in food.Withthis
increase in understanding a new, moresophisticated,way emerged to guarantee
foodsafety.Thisrelied on the use of certainprocessconditions(minimum time
and temperature of heating)that wouldguarantee the destructionof a target
microorganism in the foodunderconsideration.A well-knownexample is the
developmentof processconditionsfor the sterilisation of low-acid canned foods
by Estyand Meyer(1922).Theyderivedminimumtime±temperaturevaluesfor
the destruction of sporesofClostridium botulinum, in orderto minimisethe risk
of botulism.
310 Handbookof hygiene controlin the foodindustry