tacklingthe breedinggrounds of the fliesthemselves.At muchthe sametime,
attention beganto focuson the presenceof pathogenic bacteriain the intestines
of animals,as a sourceof foodcontamination, and foodsof animalorigin,as
routes of transmissionto humans.
Savage(1909)observed thatfaecalcontaminationof foodmust be very
common.Milk,in particular,was suspected to be a vehicleof infection.Theodor
Escherich, a German paediatrician, who devotedhis efforts to improving
childcare, particularly in relationto infanthygieneand nutrition,was the first to
make a plea for heat-processingof milkto prevent infantdiarrhoea (Escherich,
1890).Afterthat time,the heatingprocesses usedfor foodbeganto improve. Real
progress wasmade when Estyand Meyer(1922)developedthe concept of
process-performance criteria for heat treatment of low-acid,canned food-
products to reducethe risk of botulism. Later,manyotherfoodssubjectedto heat
treatmentwerecontrolledin the samemanner.An outstandingexample is the
work of Enrightet al.(1956,1957),who established performance criteria for the
pasteurisation of raw milkthat providedan appropriatelevelof protection against
Coxiellaburnetii, the causative agentof Q fever.Studieson the agentresponsible
for tuberculosis had beencarried out earlier.Theseare earlyexamples of the use
of risk-assessmentprinciplesin deriving processcriteriafor control purposes.
The recognition of animalreservoirsofSalmonellaservedto reinforcethe
perceivedcomplexityof the foodpoisoningproblem.It was known that the key
to preventingtyphoid lay in blockingthe routes by whichthe causative bacteria
might passfromanimalsto humansand thenamongthe human population.
Fromthe publichealth viewpoint, it became clear thatthere wereseveral
elementsin the foodpoisoning situation: firstly, therewas the animal-health
aspect, withveterinary,slaughterhouseand culinary factors to consider;then,
therewasthe matterof personal hygiene, whichinvolvedtoiletand hand-
washing habits. The question of developing suitable legislation was also
apparent and,finally,therewas the bacteriologicalaspect,withthe needfor
more extensivelaboratoryprovisionto helpin unravellingevidencefromthe
field.Basedon the needto improve hygienein slaughterhouses, the USAwas
one of the firstcountriesto introducea MeatInspectionAct in 1906.This
brought the followingreformsto the processing of cattle,sheep, horses,swine
and goatsdestinedfor human consumption:
∑ all animals were required to pass an inspection by the US Drug
Administrationpriorto slaughter;
∑ all carcasses weresubject to a post-morteminspection;
∑ standardsof cleanlinesswereestablished for slaughterhousesand processing
plants.
In the UK,it wasrecognisedthat legislation alone wasnot sufficient to
protect consumers againstfoodborne diseases, and the healthauthorities became
aware of the needfor publiceducation to achievecleanerfoodsupplies. Food
handling practices were very poor. Someexamples from the 1920s were
describedby Porter (1924±1925)and included the following:
10 Handbookof hygiene controlin the foodindustry