dr. marcos rostagno - pre-harvest risk factors for salmonella in pork production - pip

Pre-Harvest Risk Factors for Pre-Harvest Risk Factors for SalmonellaSalmonella in Pork Production in Pork Production

Marcos H. RostagnoMarcos H. Rostagno, DVM, MPVM, PhD, DVM, MPVM, PhD

Research Animal Scientist / Adjunct FacultyResearch Animal Scientist / Adjunct Faculty

USDA-ARS / Purdue UniversityUSDA-ARS / Purdue University

BIVI – NC Swine Health – August/2013

How important is food safety???How important is food safety???

The world is changing…The world is changing…

……and so is “our world”!and so is “our world”!

Animal ProductionAnimal Production

Food ProductionFood Production

Priorities driving consumer food choicesPriorities driving consumer food choices(Center for Food Integrity, 2012)(Center for Food Integrity, 2012)

SafetySafetyAffordabilityAffordability

NutritionNutrition(56.87%)(56.87%)

ProductivityProductivityProfitabilityProfitability

(8.12%)(8.12%)

EnvironmentEnvironmentWelfareWelfare(35.01%)(35.01%)

Food Security + SafetyFood Security + Safety

Food Safety Issues:Food Safety Issues:

Chemical hazardsChemical hazards

Physical hazardsPhysical hazards

Biological hazardsBiological hazards

. Pathogens. Pathogens

. Antimicrobial Resistance. Antimicrobial Resistance

Quality assurance

Complex challengesComplex challengesOn-farm (pre-harvest) focusOn-farm (pre-harvest) focus

SalmonellaSalmonella

How important is How important is SalmonellaSalmonella??????

How important is How important is SalmonellaSalmonella in pork??? in pork???

??

Scallan et al. (2011)

According to USDA-ERSAccording to USDA-ERS$2.3 billion (in 1998 U$)$2.3 billion (in 1998 U$)

Medical costsMedical costs++

Productivity lossesProductivity losses

Frenzen et al.(1999)

Hoffmann et al.(2012)

Incidence of foodborne pathogens in the U.S.

Healthy People 2010Salmonella (6.8)

Campylobacter (12.3)E. coli O157 (1.0)

Source: www.cdc.gov/foodnet/data/reports.html

SalmonellaSalmonella: a food safety priority for the pork industry!: a food safety priority for the pork industry!

Attribution: Pork products Attribution: Pork products 5-30% Human salmonellosis5-30% Human salmonellosis

US (6-9%)US (6-9%)EU (15-25%)EU (15-25%)

Salmonella prevalence + levels in the GIT(Determinants of the pork safety risk)

Berends et al.(1996):Infected pig Slaughter line = 3 - 4x risk of Salmonella-contaminated carcass

Salmonella contamination of pork occurs within abattoirs(Slaughter and processing line)

Infected pigs (“carriers”)Infected pigs (“carriers”)

Positive Salmonella tests in the PR/HACCP verificationtesting program from 1998 to 2011

(Market hogs - All sizes)

www.fsis.usda.gov

www.fsis.usda.gov

From Pig to PorkFrom Pig to Pork

SalmonellaSalmonella Prevalence and Levels in the GI tract Prevalence and Levels in the GI tract

SalmonellaSalmonella contamination risk

contamination risk

FarmFarm TransportTransport LairageLairage Harvest &Harvest &ProcessingProcessing

??????

What do we know about What do we know about SalmonellaSalmonellainfection in swine???infection in swine???

Transmission: fecal-oral + aerosolsTransmission: fecal-oral + aerosols

Rapid dissemination throughout the gastrointestinal tract, withRapid dissemination throughout the gastrointestinal tract, withfecal shedding within only 2 hours post-infectionfecal shedding within only 2 hours post-infection

Disease is very difficult to reproduce experimentally; interaction Disease is very difficult to reproduce experimentally; interaction of dose x serovar x immune statusof dose x serovar x immune status

Contaminated environment with low numbers (10Contaminated environment with low numbers (1022-10-1033 cfu) of cfu) of SalmonellaSalmonella enough to infect exposed pigs enough to infect exposed pigs

Infected pigs can carry (with no clinical symptoms) Infected pigs can carry (with no clinical symptoms) SalmonellaSalmonella in the intestinal tract and associated lymph nodes, and excrete in the intestinal tract and associated lymph nodes, and excrete high numbers of high numbers of SalmonellaSalmonella in feces intermittently or in feces intermittently or continuously for several weeks (serovar x dose x immune status)continuously for several weeks (serovar x dose x immune status)

Hurd et al.(2001)

SalmonellaSalmonella rapid infection rapid infectionin market-age pigsin market-age pigs

Environmental exposure dose:4.2 x 102 – 2.2 x 104 cfu/g

Rostagno et al.(2011)

SalmonellaSalmonella infection in finishing pigs infection in finishing pigs

On-Farm Risk FactorsOn-Farm Risk Factors

A variety of potential risk factors have been investigatedA variety of potential risk factors have been investigated

Conflicting findings/reports are very commonConflicting findings/reports are very common

It’s more complicated than we think!It’s more complicated than we think!

Jones & Richardson (2004)

Jones & Richardson (2004)

Mash Pellet P value

Enterobacteriaceae counts 4.01 log10 cfu/g 1.97 log10 cfu/g ND

Salmonella frequency 16/178 (9%) 21/451 (4.7%) 0.0375

4.8%4.8%

4.9%4.9%

3.5%3.5%

Torres et al.(2011)

Torres et al.(2011)

Rajic et al.(2007)

Additional On-Farm Risk Factors to Consider:Additional On-Farm Risk Factors to Consider:

Occurrence of clinical salmonellosisOccurrence of clinical salmonellosis

Occurrence of other infections/diseasesOccurrence of other infections/diseases-- PRRSv PRRSv-- Lawsonia intracellularisLawsonia intracellularis-- PCV2v PCV2v-- Parasites Parasites

Continuous flow x All-in/all-out systemsContinuous flow x All-in/all-out systems

Nose-to-nose contact between pensNose-to-nose contact between pens

Number of pig suppliers (or number of sources)Number of pig suppliers (or number of sources)-- Breeding herd & Growers Breeding herd & Growers

Biosecurity + Hygiene and disinfectionBiosecurity + Hygiene and disinfection-- Facilities & Employees Facilities & Employees

Gebreyes et al.(2008)

Alternative x Conventional Production SystemsAlternative x Conventional Production Systems

From the farm to the abattoir...From the farm to the abattoir...

““Peri-marketing” or “Peri-harvest”Peri-marketing” or “Peri-harvest”management practicesmanagement practices

On-farmOn-farm

TransportationTransportationAbattoirAbattoir

??


AbattoirAbattoirHolding Pens as a Holding Pens as a

Source of Source of SalmonellaSalmonella

Lots of potential stressors!Lots of potential stressors!

Lots of potential stressors!Lots of potential stressors!

Salmonella ???Salmonella ???

Does pre-slaughter stress affect pork safety risk?Does pre-slaughter stress affect pork safety risk?

Salmonella enterica Salmonella enterica prevalence:prevalence:First pull versus close out groups of market pigsFirst pull versus close out groups of market pigs

0

10

20

30

40

50

60

70

80

90

100

Bacteriology Serology

Pre

vale

nce (

%)

First Pull

Close Out

43/405 (10.6%, 95%C.I. 6.03–15.2%)vs.

80/405 (19.8%, 95%C.I. 11.3–28.2%)

85/450 (18.9%, 95%C.I. 12.7–25.1%)vs.

226/450 (50.2%, 95%C.I. 12.7–25.1%)

9.2%P<0.05

31.3%P<0.05

Rostagno et al. (2009)

Effect of transport and lairageEffect of transport and lairageon on SalmonellaSalmonella prevalence prevalence

(Field Study)(Field Study)P

reva

len

ce (

%)

a,b,c: P<0.05

Rostagno & Richert (2010)

Ctr: ControlFW: Feed Withdrawal (12 h)T: Transport (2 h)FWT: Feed Withdrawal + Transport

a

b

a

b

a aa

b

a a a a

IleumIleum CecumCecum RectumRectum

Lo

g10

CF

U/g

of

sa

mp

le

a,b: a,b: PP<0.05<0.05

SalmonellaSalmonella levels in market-weight pigs levels in market-weight pigssubjected to feed withdrawal and/or transportsubjected to feed withdrawal and/or transport

Rostagno et al. (2012)

Effect of stress on the susceptibilityEffect of stress on the susceptibilityof market-age pigs to of market-age pigs to SalmonellaSalmonella

(Transport and/or mixing)(Transport and/or mixing)

Rostagno & Lay (2012)

a

b b,c

c

aaa

b

a,b,c: a,b,c: PP<0.05<0.05 a,b: a,b: PP<0.05<0.05

C = ControlM = Mixing w/ unfamiliar pig (6 h)T = Transport (1 h)T+M = Transport + Mixing

The effect of stress on microbial populations in the intestinal tract of The effect of stress on microbial populations in the intestinal tract of swine is swine is specific to some bacteriaspecific to some bacteria, and dependent on its , and dependent on its intensity/typeintensity/type, , and on the portion of the GI tract and on the portion of the GI tract where the bacteria is locatedwhere the bacteria is located..

This is way too This is way too complicated!!!complicated!!!

Pre-slaughter stress increases shedding prevalence Pre-slaughter stress increases shedding prevalence and levels of and levels of Salmonella entericaSalmonella enterica in market-pigs in market-pigs

Increased risk of carcass contaminationIncreased risk of carcass contamination

Increased pork safety risk !Increased pork safety risk !

Cumulative Cumulative SalmonellaSalmonella fecal shedding frequency fecal shedding frequencyat 6 h post-challengeat 6 h post-challenge

41.7%b

25%a,b

0%a

a,b: P<0.05

DDGS x DDGS x SalmonellaSalmonella

Rostagno et al. (unpublished)

Cumulative Cumulative SalmonellaSalmonella fecal shedding frequency fecal shedding frequencyat 21 d (3 wks) and 35 d (5 wks) post-challengeat 21 d (3 wks) and 35 d (5 wks) post-challenge

a,b: P<0.05

40%a

25%b

a,b: P<0.05

DDGS x DDGS x SalmonellaSalmonella

80%a

50%b

Rostagno et al. (unpublished)

SalmonellaSalmonella ecology and epidemiology ecology and epidemiologyin swine populations is very dynamic!!!in swine populations is very dynamic!!!

It changes over time and between cohortsIt changes over time and between cohorts

Longitudinal sampling and testing is required for proper monitoring!Longitudinal sampling and testing is required for proper monitoring!


Variable PrevalenceVariable Prevalence

Bacteriology x SerologyBacteriology x Serology


Correlation (Spearman's rho)

between fecal bacteriologic culture

and serology prevalence estimates was moderate (0.59).

Investigation of On-Farm Investigation of On-Farm SalmonellaSalmonella Risk Factors: Risk Factors:Some Critical Issues to ConsiderSome Critical Issues to Consider

Differences and Inconsistencies Observed…Differences and Inconsistencies Observed…

-- Sampling Source (farm x abattoir) Sampling Source (farm x abattoir)

-- Sampling Design (size, selection, type) Sampling Design (size, selection, type)

-- Diagnostic Approach (bacteriology x serology) Diagnostic Approach (bacteriology x serology)

-- Diagnostic Method (sensitivity and specificity) Diagnostic Method (sensitivity and specificity)

Differences Between Production Systems…Differences Between Production Systems…

What can we do about it???What can we do about it???

SalmonellaSalmonella Control Strategy: Control Strategy:Pre-harvest x Post-harvestPre-harvest x Post-harvest

Post-harvest interventions seem to be more efficient.Post-harvest interventions seem to be more efficient.

However…However…

Pre-harvest interventions contribute to the effectiveness of Pre-harvest interventions contribute to the effectiveness of post-harvest interventions!post-harvest interventions!

Pre-harvest interventions:Pre-harvest interventions:Strict Biosecurity and Hygiene/Disinfection ProgramStrict Biosecurity and Hygiene/Disinfection Program

Risk of exposure to infection sourcesRisk of exposure to infection sources

Persistence of the pathogen in the environmentPersistence of the pathogen in the environment++

Peri-harvest transportation and lairage measuresPeri-harvest transportation and lairage measures

From breeding herd to finishers!From breeding herd to finishers!

Targeted InterventionsTargeted Interventions

In-feed or water:In-feed or water:

ProbioticsProbiotics

PrebioticsPrebiotics

Organic acidsOrganic acids

Essential oilsEssential oils

Etc, etc, etc...Etc, etc, etc...

Which one?Which one?When?When?

ManipulationManipulationof the of the

gastrointestinal gastrointestinal microbial microbial

ecosystemecosystem

There is no “silver bullet” to control There is no “silver bullet” to control SalmonellaSalmonella!!!!!!It must be done with a program!!!It must be done with a program!!!

Concluding Thought...Concluding Thought...

““The Salmonella challenge”The Salmonella challenge”

Everyone has a critical role...Everyone has a critical role...Producers, processors, retailers, and consumers!Producers, processors, retailers, and consumers!

Everyone must be committed,Everyone must be committed,or we won’t make progress!!!or we won’t make progress!!!

USDA-ARS-LBRUUSDA-ARS-LBRU. Scientists. Scientists

Dr. Donald LayDr. Donald LayDr. Susan EicherDr. Susan Eicher

. Gary Nowling. Gary Nowling

. Rita Lockeridge. Rita Lockeridge

. Kim McMunn. Kim McMunn

Purdue UniversityPurdue University. Dr. Brian Richert. Dr. Brian Richert. Dr. Paul Ebner. Dr. Paul Ebner

Iowa State UniversityIowa State University. Dr. Scott Hurd. Dr. Scott Hurd. Dr. James McKean. Dr. James McKean

Undergraduate & Graduate StudentsUndergraduate & Graduate Students

AcknowledgementsAcknowledgements

dr. marcos rostagno - pre-harvest risk factors for salmonella in pork production - pip

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