Facts on Foodborne Pathogens 1
Foodborne disease is caused by consuming contaminated foods or beverages. Many different disease causing microbes, or pathogens, can contaminate foods, so there are many different foodborne infections. Use this resource as a reference on foodborne bacterial and non-bacterial agents that can potentially result in food contamination.
Manitoba Agriculture, Food and Rural Initiatives assumes no legal liability for results obtained from using this material.
ContaCt InformatIonFor information on the Food Safety Program visit: manitoba.ca/agriculture/foodsafety
For more technical information or to obtain a copy of this publication, call 204-795-7968 in Winnipeg, or e-mail [email protected].
2 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:aerobic• temperaturerangeforgrowth:5-55ºC•pHrangeforgrowth:4.3minimum,9.3maximum•wateractivityforgrowth:0.912-0.95•motile,spore-formingorganism•sporesresistheatanddryenvironmentconditions
foods at risk•boiledorfriedricestoredatroomtemperature•starchyfood(pasta,noodles,potatoproducts)•cookedvegetablesandsalads•cookedmeat(mincebeef,veal,lamb,pork,poultry)• ready-to-eatfoods•driedherbsandspices•driedproductssuchascerealsandflours•cream(‘sweetcurdling’or‘bittycream’spoilage)•puddings,saucesandsoups
Sources•distributedinsoil,dust,air,wateranddecaying
organic matter
Bacillus cereus
foodborne baCterIal agentS
Facts on Foodborne Pathogens 3
risk to consumers•diarrhea•vomiting
transmission• ingestionofcontaminatedfood
Prevention •vegetativecellsdestroyedbyheat(56ºC,5minutes)•sporesdestroyedbyheat(126ºC,90min)•sporesloseheatresistanceinacidicenvironments,
reducepHoffoodto<4.3•mostchemicalsanitizersdestroyB. cereus on surfaces •reducewateractivityto0.921•preservativeswhichhaveaneffectonB. cereus
include:benzoate,EDTAandsorbate
testing •PEMBAagarusedforidentification;thebacteria
coloniesretainaturquoise-bluecolorafter24hours ofincubationat37ºC
•commercialkitsalsoavailable
In general•cookfoodthoroughlyandcoolrapidlyto
prevent spore germination•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
4 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:micro-aerophilic(lowlevels
ofoxygen3-5%)• temperaturerangeforgrowth:25-45ºC•pHrangeforgrowth:4.9minimum,9.5maximum•wateractivityforgrowth:0.987-0.997•non-spore-formingorganism•motile
foods at risk•meatcarcassescontaminatedwithintestinal
contents during slaughter and evisceration •rawpoultry•shellfish•rawmilk•redmeat•salads•mushrooms
Sources•alimentarytractofwild,domesticatedanimals andbirds,sewage
Campylobacter jejuni
foodborne baCterIal agentS
campylobacter
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Facts on Foodborne Pathogens 5
risk to consumers•gastrointestinaldisease
transmissionFoodisavehiclefortransmission.Directtransmissionperson-to-personorfromcontactwithinfectedanimals.
Prevention • inactivatedbyheatingat55ºCandabove,cannot
survivecookingorpasteurizationtemperatures•sensitivetodrying•reducepHoffoodto<4.9,rapiddeathespecially
above refrigeration temperatures•survivespoorlyatatmosphericoxygenconcentrations
and room temperature•sensitivetoNaClconcentrationsabove1%•ascorbicacidinhibitsgrowthofseveralspecies•sensitivetosanitizers,ex:chlorine•sensitivetoultravioletradiation
testing • incubationmedia(FBP)containingblood,pyruvate,
ferroussalts,charcoalandmetabisulfite
In general•avoidcrosscontaminationfromrawfoods
tocookedfoods•reheatcookedfoodto74ºC
6 Facts on Foodborne Pathogens
Characteristics•Motileandspore-formingbacteria,extremelyheat-resistantspores.ToxinproducedatpH4.83-5.2.
group I, type a, b and f (proteolytic)•oxygenrequirements:anaerobe• temperaturerangeforgrowth:10-48ºC•pHrangeforgrowth:4.6minimum,9maximum•wateractivity:0.935minimum
group II, type b, e and f (non-proteolytic)•oxygenrequirements:anaerobe• temperaturerangeforgrowth:3.3-45ºC•pHrangeforgrowth:5minimum,9maximum•wateractivity:0.970
foods at risk•uncookedvegetables(typeA)thathaveclosecontactwiththeground(asparagus,potatoes,cabbage)andgrains
•smokedandsaltedfish,seafood(typeE)•sporesgerminateinlow-acidfrozenorcoldfood•cannedproducts:vegetables,meat,corn,peppers,greentomatoes,chicken,ham,sausage,lobster
•honey
Sources•distributedindust,mud,waterandanimalcarcasses
Clostridium botulinum
foodborne baCterIal agentS
Facts on Foodborne Pathogens 7
risk to consumers•botulismcausedbytoxin,neurologicalsymptoms
transmission• foodcontaminatedwithsporesorvegetativecells
Prevention •sporeinactivationinlow-acid(pH>4.3)foodsby
heatingto121ºCfor3minutes• toxininactivatedbyheatingto85ºCfor1minute,
80ºCfor6minutesor65ºCfor1.5hours•vegetativecelldestroyedbyfewminutesexposureto60ºC• thermaldeathincreaseatextremepH(<5&>9)•groupIinhibitionby10%NaClandgroupII
inhibitionby5%NaCl• toxininactivationbypH11•reducepHoffoodto≤4.6•useofpreservatives,ex:nitrite,sorbates,EDTA• lacticacidbacteriaaddedinstartercultures
inhibitgrowthinmeatproducts•sporesinactivatedbyozoneorchlorinedioxide
testing •horse-bloodoregg-yolkagarincubatedanaerobically
for3days,coloniesshowlipolyticactivity
In general•holdfoodsat≤3.3ºCor≥60ºC•coolcookedfoodsunderrefrigeration
8 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:anaerobe• temperaturerangeforgrowth:10-52ºC•pHrangeforgrowth:5minimum,9maximum•wateractivityforgrowth:0.93-0.95•spore-former,heatresistantspores(upto100ºC)•non-motile•producesenterotoxins
foods at risk•cookedmeat:stews,roastjoints•gravies,thicksoups,vegetablecurry(heatingdrives
air off and creates anaerobic conditions for spores togerminate)
•pies•poultrydishes,preparedinadvanceandallowed
tocoolslowly•rolledmeatsandstuffedpoultry
Sources•distributedinsoil,dust,water,vegetationandhuman
gastrointestinal tract
Clostridium perfringens
foodborne baCterIal agentS
Facts on Foodborne Pathogens 9
Clostridium perfringensrisk to consumers•gastroenteritis:diarrheaandabdominalpain•woundinfectionandgasgangrene
transmission• ingestionofcontaminatedfoods
Prevention •vegetativecellsaredestroyedbyheatingorby
freezing•enterotoxinsinactivatedbyheatingfor5minutesat60ºC•vegetativecellsgrowthispreventedat<12ºC•6-8%NaClinhibitsgrowth•curingsalts(ex:sodiumnitriteandchloride)can
inhibitgrowth•pHbelow5andabove8.3destroycells•highconcentrationofethanol(assanitizer)cause
spore death on food contact surfaces
testing •TSCandOPSPmediacontainingantibiotics,
incubatedanaerobicallyfor24hoursat37ºC•commercialkitsavailable
In general•cookfoodthoroughlyandcoolrapidlyto
prevent spores germination•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
10 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:facultativeanaerobe• temperaturerangeforgrowth:10-44.5ºC•pHrangeforgrowth:4.4minimum,9maximum•wateractivity:0.95minimum•non-spore-forming•non-motile• indicatoroffaecalcontaminationandthepossible
presence of enteric pathogens (ex: Salmonella typhi)•notheatresistant•survivesfrozenstorageforashortperiodoftime
foods at risk•rawmilk•rawmeat• rawpoultry•rawvegetables• foodsthatarehandledunderpoorhygienic
conditions
Sources• intestinaltractofhumanandwarm-bloodanimals, soilandwater
Escherichia coli
foodborne baCterIal agentS
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Facts on Foodborne Pathogens 11
foodborne baCterIal agentS
risk to consumers•gastroenteritis:diarrhea,vomiting,stomachpain•urinarytractinfections
transmission• faecalcontaminationofwatersuppliesandcontaminated
food due to poor hygiene practices of food handlers
Prevention •rapidlyinactivatedbyheating•destroyedatpHvaluesoutsidetherangeallowing
growth(pH4.4-9)•growthcanbeinhibitedbyaslightlyacidic
environment(ex:acetic,lacticacid)• followGoodManufacturingPractices(GMPs),ex:
goodpersonnelpracticesfollowedbyfoodhandlers• thoroughlywashingoffruitsandvegetables
testing •eosin/methyleneblueagar•ß-glucuronidaseactivity,testedbyaddinga
fluorogeniccompound(MUG)inthemedia• IMViC,groupofteststodifferentiateE. coli from othermembersoftheEnterobacteriaceaegroup
In general•cookfoodthoroughlyandcoolrapidly•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
12 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:facultativeanaerobe• temperaturerangeforgrowth:10-44.5ºC•pHrangeforgrowth:4minimum,9maximum•wateractivityforgrowth:0.950-0.995•non-spore-forming•surviveswellinchilledorfrozenfood•non-motile•producepotenttoxinsthatcauseseveredamage
to the lining of the intestine
foods at risk•undercookedgroundmeat:(ex:rawhamburgers)• rawmilk•alfalfasprouts•unpasteurizedfruitjuice(ex:applejuice)• lettuce•cheesecurds•dry-curedsalami,fermentedsausages
Sources•cattle,cows,sheepanddeer,watercontaminated
from faecal sources
Escherichia coli o157:H7
foodborne baCterIal agentS
Facts on Foodborne Pathogens 13
foodborne baCterIal agentS
risk to consumers•hemorrhagiccolitis(bloodydiarrhea)•hemolyticuremicsyndrome(acuterenal
failure,anemia)
transmission•contaminatedfoodorwater,person-to-person
transmission due to poor personal hygiene
Prevention •rapidlyinactivatedbyheating•cookbeefhamburgersuntilthecentrereaches
atemperatureof71.1ºC(160ºF)• thoroughlywashfruitsandvegetables•acidifyfoodstopH3.6orbelow•benzalkoniumchloride,ethanolorhotwater(70ºC)
areeffectivefoodcontactsurfacesanitizersiforganicmatter is not present
•sensitivetoultravioletradiation
testing • testsforE. coli are not sensitive to E. coliO157:H7• latexagglutinationkitscommerciallyavailable•serologicaltests
In general•cookfoodthoroughlyandcoolrapidly•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
14 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:facultativeanaerobe• temperaturerangeforgrowth:-0.4-50ºC•pHrangeforgrowth:4.4minimum,9.6maximum•wateractivity:0.92minimum•non-spore-forming•salttolerant,ex:cangrowin10%sodiumchloride•growsatrefrigerationconditions
foods at risk•rawmilk•cheeses(soft-ripenedvarieties)• icecream•rawvegetables•rawandfermentedmeatsausages•rawmeats(alltypes)• rawandsmokedfish•ready-to-eatfoodscontaminatedaftercooking
Sources•soil,water,sewage,domesticatedanimals,drains,
condensate,pooledwater,crackedorworntiles,ventilationsystemsandfilters
risk to consumers• listeriosis(influenza-likesymptoms,meningitis),affects
newborns,elderly,pregnantwomenandimmunecompromised individuals
Listeria monocytogenes
foodborne baCterIal agentS
Listeria
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Facts on Foodborne Pathogens 15
foodborne baCterIal agentS
transmission•contaminatedfood,ready-to-eatfoodswithlongshelf
live(ex:hotdogsanddelimeats—contaminationmayoccuraftercookingbutbeforepackaging),
•person-to-personspread
Prevention •growthisinhibitedatpHvaluesbelow4.4• inactivatedattemperaturesabove70ºC• inactivatedinvegetablesbylysozyme•sanitizers(aldehydes,alcohols,quaternary
ammoniumcompounds)areeffectiveineliminatingcontamination of food contact surfaces
•sensitivetoultravioletradiation•holdfoodsat<5ºCupto7days•holdfoodsat<7.2ºCupto4days
testing •selectiveagarscontaininglithiumchloride,
phenylethanol, glycine anhydride and antibiotics•CAMPtest(productionofacharacteristiczoneof
hemolysiswhengrowninproximitytoS. aureus)
In general•reheatcookedfoodto74ºC•avoidpost-cookingcontaminationof
ready-to-eatfoodswithlongshelflives
16 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:facultativeanaerobe• temperaturerangeforgrowth:5-47ºC•pHrangeforgrowth:3.7minimum,9.6maximum•wateractivityforgrowth:0.93-0.95•non-spore-forming•motile•heatsensitive•survivesinrefrigerated,frozenordehydratedfoods
for long periods
foods at risk•undercookedmeatandpoultry•unpasteurizedmilk•eggsandeggsproducts(eggshellcontaminatedwith
faecalmaterialinthehen’scloaca,eggwhiteandyolkcontaminatedwhenbreakingtheegg)
•mayonnaisepreparedwithraweggs
Sources•gastrointestinaltractofanimals,hogs,rodents,pets,
birds, reptiles, insects
Salmonella
foodborne baCterIal agentS
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Facts on Foodborne Pathogens 17
foodborne baCterIal agentS
risk to consumers•Salmonellosis:gastrointestinalinfection•Typhoidfever(causedbyS. typhi):fever,
headache, constipation, chills
transmission• ingestionofcontaminatedfood.•disseminatedviaanimalandhumanfaeces tosoilandwater
Prevention •avoiddirecthandlingoffoodbyinfectedemployees•acidifyfoodsatpH3.8orbelow• thoroughlywashfruitsandvegetables•heatsensitive,thermaldestruction•growthinhibitedby0.1%aceticacid•notresistanttosanitizersusedinthefoodindustry•pasteurizationofraweggs,milk
testing • impedance-conductancetechniquesusing
TMAOculturemedium•ELISAkitscommerciallyavailable
In general•cookfoodthoroughlyandcoolrapidly•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
18 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:facultativeanaerobe• temperaturerangeforgrowth:6.1-47ºC•pHrangeforgrowth:4.8minimum,9.3maximum•wateractivity:0.96minimum•non-spore-forming•non-motile•survivesbetteratlowtemperatures
foods at risk•uncookedprawn•salads:tuna,shrimp,chicken•rawvegetables•slicedfruitsatroomtemperature
Sources•gastrointestinaltractofhumansandother
primates,water
risk to consumers•Shigellosis(bacillarydysentery:abdominal
discomfort, cramps, diarrhea, fever, vomiting, blood,pusormucusinstools)
Shigella
foodborne baCterIal agentS
Facts on Foodborne Pathogens 19
foodborne baCterIal agentS
transmission• ingestionofcontaminatedfoodsthroughfecal-oral
route,faecallycontaminatedwater,unsanitaryfoodhandlingandfliescarryingsewagecontamination
Prevention •rapidlyinactivatedattemperaturesabove65ºC• inactivatedatpHvalues<4• thoroughlywashfruitsandvegetables•avoidcontaminationofready-to-eatfoodsfromflies
testing •Gram-negativebrothandselenitebroth•rapidtechniquesbasedonimmunoassays•polymerasechainreaction(PCR)
In general•cookfoodthoroughlyandcoolrapidly•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
20 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:facultativeanaerobe• temperaturerangeforgrowth:7-50ºC•pHrangeforgrowth:4minimum,10maximum•wateractivity:0.83minimum•enterotoxinproduction•heatresistant•salttolerant(cangrowinup20%sodiumchloride)•producetoxins,especiallyinthepresenceofoxygen
and high numbers
foods at risk•rawpoultry,poultryproducts,coldcookedmeats•rawmilk,hardcheeses•saltedmeats(ex:ham,cornedbeef)•coldsweets,custardsandcream-filledbakery
products• foodrequiringconsiderablehandlingduring
preparationandkeptatslightlyelevated temperatures after preparation
Sources•skin,skinglandsandmucousmembranesofwarm
blooded animals, humans nasal tract, soil, marine andfreshwater,plantsurfaces,dustandair
Staphylococcus aureus
foodborne baCterIal agentS
Facts on Foodborne Pathogens 21
risk to consumers•nausea,vomiting,stomachcramps,diarrhea
transmission• foodcontaminatedbyfoodhandlersfromskin
lesions,bycoughingandsneezingoverfoods
Prevention •duringfoodfermentation,lacticacidbacteria
produce substances that are inhibitory to S. aureus, including:lacticacid,sorbateandbenzoate
•chemicalsanitizerssuchaschlorine,halogens andquaternaryammoniumcompoundseliminate S. aureus on food contact surfaces
•reducepHoffoodto≤4.2•reducewateractivityto0.83•avoiddirecthandlingofcookedready-to-eat
foods or cured/salted foods
testing •Baird-Parkeragargivescharacteristicshiny, jet-blackcoloniessurroundedbyaclearingzone
•enterotoxinidentificationfromcontaminated foodidentifiedbyELISAorreversepassive latexagglutinationtest
In general•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
22 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:facultativeanaerobe• temperaturerangeforgrowth:10-45ºC•pHrangeforgrowth:5minimum,10maximum•wateractivity:0.94minimum•non-spore-forming•produceapotenttoxin• toleranttoalkalineconditions
foods at risk• fruitsorvegetableswashedwithcontaminatedwater
andconsumedwithoutcooking• foodscomingfromacontaminatedenvironment:seafoodandfrog’slegs
•uncookedfishmarinadeinlime•fishandshellfish(raworpartiallycooked)•rawoysters
Sources•marineenvironment:temperate,tropicaland
sub-tropicalwaters•contaminatedwatersuppliesduetopoorsanitation
Vibrio cholerae
foodborne baCterIal agentS
Facts on Foodborne Pathogens 23
risk to consumers•profusewaterydiarrhea,vomiting,legcramps•rapidlossofbodyfluidsthatleadstodehydration
andshock
transmission•waterborneinfection,ingestionoffoodthatwas
incontactwithcontaminatedwater
Prevention •rapidlyinactivatedatpHvalues<4.5•sensitivetodrying• thoroughlywashallfruitandvegetables•avoidcrosscontaminationfromrawtocookedfoods•avoiddirectfoodhandlingbyinfectedemployees•peraceticacidandhypochloriteareeffectivefood
contactsurfacesanitizersintheabsenceofprotein
testing •TCBSagarincubatedfor18-24hoursat35°C
aerobicallyproducesyellowcolonies
In general•keephotfoodsabove60ºCandcoldfoods
below4ºC
24 Facts on Foodborne Pathogens
Characteristics•oxygenrequirements:facultativeanaerobe• temperaturerangeforgrowth:-1-40ºC•pHrangeforgrowth:4.2minimum,10maximum•wateractivity:0.945minimum•non-sporeforming•motile• tolerate6%salt• resistenvironmentalstress:highpH,dehydration,
freezing
foods at risk•meats(beef,lamb)•raworundercookedporkproducts•oysters•rawmilk•shellfish•dairyproducts• fruitandvegetables
Sources•soil,freshwater,intestinaltractofmanyanimals.
Yersinia enterocolitica
foodborne baCterIal agentS
Facts on Foodborne Pathogens 25
foodborne baCterIal agentS
risk to consumers•gastroenteritis:abdominalpain,diarrhea,mildfever
transmission•person-to-persontransmission,byingestionof
contaminatedfoodandwaterbornetransmission
Prevention •pasteurization•5-7%sodiumchlorideinhibitsgrowth• inactivatedbyapHvaluelowerthan4.2•growthisretardedbypotassiumsorbateupto
500ppmatpH6.5•sensitivetoultravioletradiation•avoiddirecthandlingoffoodbyinfected
food handlers•avoidpost-processingcontaminationofready-to-eat
foodswithalongshelflife
testing •CINagarincubatedat28ºCfor24hoursproduces
dark-redcentresurroundedbyatransparentbordercolonies
In general•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
26 Facts on Foodborne Pathogens
Characteristics•protozoa,intracellularparasite•mostlikelytobepresentasanoocyst(restingstage
equivalenttoabacterialspore)•oocystsurvivesonstainlesssteelifkeptwet•oocystsurvivesheatingat60ºCfor1minute•resistanttochlorine
foods at risk•rawmilk•rawsausages(non-fermented)•anyfoodtouchedbyacontaminatedfoodhandler•saladvegetablesfertilizedwithmanure
Sources• livestock,calves,domesticanimalsandwaterfaecally
contaminated
risk to consumers•diarrhea•seriousinfectioninimmunocompromisedpersons•abdominalpain•nausea•vomiting
Cryptosporidium parvum
foodborne non-baCterIal agentS
Facts on Foodborne Pathogens 27
foodborne non-baCterIal agentS
transmission•person-to-persontransmission,byingestionof
contaminatedfoodandwaterbornetransmission
Prevention •pasteurization• temperatureabove73ºCrendertheoocyst
non-infectious• inactivatedbyfreezingat–15ºC•acidconditions(pH4)resultsinlossofoocystviability•sensitivetodrying•sensitivetoultravioletlight•0.35%peraceticacidinactivatesoocysts•avoidcrosscontaminationfromrawtoready-to-
eat foods• thoroughlywashfruitsandvegetables
testing •EnzymeImmunoAssay(EIA)andImmunoFluorescent
Antibody(IFA)(bothdirectandindirectmethods)candetect Cryptosporidium
In general•keephotfoodsabove60ºCandcoldfoods
below4ºC•reheatcookedfoodto74ºC
28 Facts on Foodborne Pathogens
CharacteristicsRotavirus,astrovirus,hepatitisE,adenovirus,calicivirus:
•donotreplicateinfood,requirehumancellstomultiply
•passthroughthegastrointestinaltract
• resistanttoenvironmentalstresssuchasheatand acid conditions
•stableatpH3
•resistfreezinganddrying
foods at risk• foodsmaybecomecontaminatedduring:handling,
preparation, serving or processing •salads•shellfishgrowninshallow,coastalwaters
Sources•contaminatedwaterandcontaminationbyinfected
food handlers
risk to consumers•diarrheaandvomiting•severechildhoodgastroenteritis
Enteric Viruses
foodborne non-baCterIal agentS
(otherthanhepatitisAandnoroviruses)
Facts on Foodborne Pathogens 29
foodborne non-baCterIal agentS
transmission•allfoodbornevirusesaretransmittedbyfecal-
oral route •canalsobetransmittedbyingestingcontaminated
foodsthatundergoextensivehandlingintheir preparationandareconsumedwithoutreheating
Prevention •heatingfor30minutesat50ºC•reducepHlevelsto<3orincreasetopH>10• thoroughlywashfruitsandvegetables• thoroughcleaninganddisinfectionmustfollow
after vomiting on food premises• foodhandlerstrainedineffectivehandwashingtechniques
testing •rapidantigendetectionofentericvirusinstool
samples •strainsfurthercharacterizedbyenzymeimmunoassay
In general•reheatcookedfoodto74ºC•boil,filterortreatnon-potablewaterbefore
drinking
30 Facts on Foodborne Pathogens
Characteristics•survivesinfoodandwaterascysts(infectiveform)
•watersurvivalatlowtemperatures(~8ºC)
•coolmoistconditionsfavorsurvival
•cystsresistanttoultravioletradiationandchlorination
foods at risk•salads•vegetablessuchaslettuce• fruitssuchasstrawberries• foodswashedwithcontaminatedwaterorhandled
by infected employees•herbs• rootcrops(beet,carrot)
Sources•environmentalwaterswhichhavebeenfaecally
polluted• foundinanimals,birds,reptilesandamphibians
risk to consumers•Giardiasis:diarrhea,abdominalcramps,nausea,weightlossanddehydration
Giardia lamblia
foodborne non-baCterIal agentS
Facts on Foodborne Pathogens 31
foodborne non-baCterIal agentS
transmission•person-to-personduetopoorhygiene•contaminatedwater,foodcontaminatedbywater
or by a food handler
Prevention •cystseliminatedbynormalcookingprocedures
in food preparation•heatingfoodto60-70ºCfor10min•boilingfor3minutes•pasteurization•cystsinactivatedbyfreezing•waterfiltration(8μmporesizefilter)•avoidcrosscontaminationfromrawto
ready-to-eat foods• thoroughlywashfruitsandvegetables•avoidfoodhandlingbyinfectedemployees
testing •detectioninstoolsamplesbymicroscopicexamination•ELISAtest
In general•reheatcookedfoodto74ºC•boil,filterortreatnon-potablewaterbefore
drinking
32 Facts on Foodborne Pathogens
Characteristics•highresistancetochemicalandphysicalagents,
including: heat, acid and solvents
•underfreezingandrefrigerationconditions the virus remains infective
•stableatpH1
foods at risk•milk• fruits(strawberries,raspberries)•saladvegetables(lettuce)•shellfish•manuallypreparedfoodproducts•cream-filledcookies•coldcuts(precookedorcuredmeat,sausages
or meat loaves, that are sliced and served on sandwichesoronpartytrays)
Sources•humanfaeces,contaminatedwater(freshand
seawater,wastewater,marinesediments)andsoil
Hepatitis a Virus (HaV)
foodborne non-baCterIal agentS
Facts on Foodborne Pathogens 33
foodborne non-baCterIal agentS
risk to consumers•hepatitisA:fever,nausea,vomiting,liverdamage,malaise,anorexia,jaundice
transmission•Transmissionoccursbythefecal-oralroute,eitherby
directcontactwithaHepatitisAvirusinfectedpersonorbyingestionofHepatitisAviruscontaminatedfoodorwater.
Prevention •cookshellfishat90ºCfor1.5min• thoroughlywashallfruitandvegetables•avoidhandlingoffoodbyinfectedemployees•ensuretrainingoffoodhandlersineffectivehand
washing(asymptomaticfoodhandlerscanspread theinfection)
• infectivityisdecreasedbyexposureto70%alcohol• inactivatedbyultravioletradiation
testing • foodisrarelyanalyzedbecauseofthelongincubationperiod(2-6weeks)
In general•boil,filterortreatnon-potablewaterbefore
drinking
34 Facts on Foodborne Pathogens
Characteristics•mostwidelyrecognizedviralagentassociated
withfoodandwaterborneoutbreaks
•stableandresistanttoheatandacidicconditions
•underrefrigerationandfreezingconditionsthe virus remains intact
•resistgastricacidsatpH3-4
•resistanttodrying
foods at risk•shellfish,raworinsufficientlysteamedclams
andoystersposesahighrisk•salads•waterandice•manuallypreparedfoodproducts•bakeryproducts
Sources•environmentalsurfaces(ex:carpets),fecesfrom
infectedhumansmaycontaminatesoilorwater• fecalpollutionfromsewagedischarges
norovirus
foodborne non-baCterIal agentS
Facts on Foodborne Pathogens 35
foodborne non-baCterIal agentS
risk to consumers•projectilevomiting•stomachcramps•diarrheaandabdominalpain
transmission• ingestionofcontaminatedfoodduetopoorhygiene
practices •person-to-personspreadfollowingprojectilevomiting• transmissionviacontaminatedsurfaces(carpetsand
toiletseats)
Prevention •cookshellfishat90ºCfor1.5min• thoroughlywashallfruitandvegetables•avoidhandlingoffoodbyinfectedfoodhandlers•ensuretrainingoffoodhandlersineffectivehand
washing(asymptomaticfoodhandlerscanspread theinfection)
testing •molecularmethods,includingDNAsequencing;the
virusisnon-culturableanddoesnotgrowinfood
In general•boil,filterortreatnon-potablewaterbefore
drinking
36 Facts on Foodborne Pathogens
Characteristics•bacteriaactasanindirectagentoffoodpoisoning
byconvertingafoodcomponent(histidine)intoaharmfulcompound(histamine)
•histamineisproducedduringtemperatureabuse and spoilage
•cookingorheatingdoesnotdestroyhistamine
•vacuumpackagingisnoteffectiveinretardinghistamine production
foods at risk•scombroidfish:tuna,bonito,mackerel(temperatureabusedrawfishallowsbacterialgrowthandtoxinproduction)
•fish:sardines,pilchards,herrings•cannedfish•cheese,speciallySwisscheese(ripenedat
warmtemperatures)• fermentedmeatproducts,ex:salami• fermentedvegetables,ex:sauerkraut
Sources• foodscontaminatedwithhistamine,mainlyfish
scombroid (Histamine) Poisoning
foodborne non-baCterIal agentS
Facts on Foodborne Pathogens 37
foodborne non-baCterIal agentS
risk to consumers•chemicalintoxication:diarrhea,facialandneck
rashes,inflammation,dizziness,itching,vomiting
transmission• ingestionofcontaminatedfoodwithhistamine
Prevention • incheeseproductiontheuseofstartercultures
withlowdecarboxylaseactivitypreventhistamineformation
•shortfermentationtimeformeatproducts,useappropriate starter culture and rapidly decrease thepH
• transportandstorefishunderrefrigeration•chillfishrapidlyto<10ºC•holdfishat0ºCupto14days,4.4ºCupto7days• rawfishshouldbepurchasedfromknownand
reputable suppliers
testing •FDAchemicalmethod:alcoholextractionfollowed byfluorescencespectroscopy
•Commercialkitsforhistaminedetectionavailable
In general•fishshouldberapidlyretrievedfromthewater,
cooledasquicklyaspossibleandhandledusing good hygienic procedures
38 Facts on Foodborne Pathogens
glossaryaerobe:requiresoxygen
anaerobe:requirestheabsenceofoxygen
baird-Parker agar:lithiumchloride,tellurite,eggyolkand pyruvate
CamP test: named for the initials of the 4 discovers, Christie,Atkins,MunchandPetersen
CIn agar: cefsulodin, irgasan and novobiocin
elISa:enzyme-linkedimmunosorbentassay
enterotoxin:toxinreleasedbyamicro-organisminthelowerintestine.Italtersthepermeabilityoftheintestinalwallcausingwaterandelectrolytestoleakintotheintestinal tract.
facultative anaerobe: growseitherwithorwithoutoxygen
fbP agar:ferroussulfate,sodiumbisulfiteandsodiumpyruvate
Hemolysis:breakdownofredbloodcells
ImViC test: indoletest,methylredandVoges-Proskauertest and citrate test
micro-aerophilic:requireslimitedlevelsofoxygen
mUg:fluorogen4-methylum-belliferyl-ß-D-glucuronide
naCl: sodium chloride
oPSP agar:oleandomycin,polymyxin,sulfadiazineand perfringens
Facts on Foodborne Pathogens 39
Pemba agar:polymyxin,pyruvate,eggyolk,mannitoland bromothymol blue agar
ppm:partspermillion,ex:oneparticleofagivensubstance for every 999,999 other particles
tCbS agar: thiosulfate, citrate, bile salt and sucrose
tmao: selenite-cysteine broth containing dulcitol andtrimethylamineoxide
tSC agar:tryptose,sulfiteandcycloserine
40 Facts on Foodborne Pathogens
manitoba agriculture, food and rural Initiativesmanitoba.ca/agriculture/foodsafety
ESR-004724