Introduction to Non-O157 Introduction to Non-O157 STECsSTECs

JamesJames Marsden Marsden Distinguished ProfessorDistinguished Professor

Food Safety and SecurityFood Safety and SecurityKansas State UniversityKansas State University

SteakExpert 2012 SteakExpert 2012

What we know about STECsWhat we know about STECs

Emerging STECs (Shiga Toxin Producing Emerging STECs (Shiga Toxin Producing strains of E. coli)strains of E. coli)

  Six strains of STECs have been associated Six strains of STECs have been associated with ¾ of the food safety illnesses in the with ¾ of the food safety illnesses in the United States  (O26, O45, 0103, O111, O121, United States  (O26, O45, 0103, O111, O121, and O145 -- termed the “Big Six).and O145 -- termed the “Big Six).

What we know about STECsWhat we know about STECs

Illnesses associated with STECs are Illnesses associated with STECs are identical to identical to E. coli E. coli O157:H7O157:H7

Symptoms include diarrhea, bloody Symptoms include diarrhea, bloody diarrhea, HUS and deathdiarrhea, HUS and death

Increased reports of illnesses may be due Increased reports of illnesses may be due to a higher prevalence of possibly improved to a higher prevalence of possibly improved surveillance surveillance

FoodNet reported 575 STECs between FoodNet reported 575 STECs between 2000 – 2006 (209 in 2006)2000 – 2006 (209 in 2006)

What we don’t know about What we don’t know about STECsSTECs

No one really knows how prevalent these No one really knows how prevalent these STECs are in nature or in the food supplySTECs are in nature or in the food supply

FSIS estimates that the incidence in dairy FSIS estimates that the incidence in dairy cattle may be between 0-19% and the cattle may be between 0-19% and the incidence in beef cattle feces and hides incidence in beef cattle feces and hides may be 19.4 – 56.3%; Pre-evisceration may be 19.4 – 56.3%; Pre-evisceration beef carcasses – >50%; Retail Ground beef carcasses – >50%; Retail Ground Beef – 2-3%Beef – 2-3%

What we don’t know about What we don’t know about STECsSTECs

  The beef industry has been successful in The beef industry has been successful in reducing the incidence of E. coli O157:H7reducing the incidence of E. coli O157:H7

We don’t know for certain whether the same We don’t know for certain whether the same interventions that are effective on interventions that are effective on E. coli E. coli O157:H7 will also inactivate STEC strains. O157:H7 will also inactivate STEC strains.

We don’t know enough about thermal We don’t know enough about thermal resistance, acid resistance, effect of Aresistance, acid resistance, effect of Aww and and HPPHPP

We don’t know to what extent STECs are We don’t know to what extent STECs are associated with beefassociated with beef

What we need to know about What we need to know about STECsSTECs

The ideal approach to the challenges posed by STECs The ideal approach to the challenges posed by STECs would first involve a national baseline study and risk would first involve a national baseline study and risk assessment assessment

Secondly, research is needed to identify and validate Secondly, research is needed to identify and validate effective interventions. effective interventions.

Thee beef industry has been focused on interventions for E. Thee beef industry has been focused on interventions for E. coli O157:H7 since the 1993 Jack-in-the-Box outbreakcoli O157:H7 since the 1993 Jack-in-the-Box outbreak

It’s possible that the food safety systems already in place for It’s possible that the food safety systems already in place for control of control of E. coliE. coli O157:H7 are effectively controlling nSTECs  O157:H7 are effectively controlling nSTECs as well. However, that needs to be proven.as well. However, that needs to be proven.

What we need to know about What we need to know about STECsSTECs

We need to better understand the biology We need to better understand the biology of STECs of STECs

We need to determine the thermal We need to determine the thermal resistance, acid resistance, effect of Aresistance, acid resistance, effect of Aww and HPPand HPP

We need to identify modes of We need to identify modes of contamination and whether they are contamination and whether they are similar to similar to E. coli E. coli O157:H7O157:H7

PathogenicityPathogenicity

Not all Not all E. coli E. coli strains are pathogenic.strains are pathogenic.To be pathogenic, a strain must have the To be pathogenic, a strain must have the

necessary properties to cause disease in necessary properties to cause disease in human.human.

These properties are called “virulence These properties are called “virulence factors.”factors.”

Exactly what virulence factors are required Exactly what virulence factors are required is unknown.is unknown.

PathogenicityPathogenicity

• E. coli E. coli can cause human disease when they can cause human disease when they possess possess stx1stx1 or s or stx2tx2..

• Individuals infected with strains producing stx2 Individuals infected with strains producing stx2 are are more likely to develop severe disease than more likely to develop severe disease than those infected with strains carrying Shiga toxin 1.those infected with strains carrying Shiga toxin 1.

• It is commonly thought that It is commonly thought that E. coli E. coli must contain must contain stx1stx1 or or stx2stx2 and and eaeeae (intimin) (intimin) and its substitutes and its substitutes to to have the highest chance of causing disease in have the highest chance of causing disease in humans – of course there are always exceptions.humans – of course there are always exceptions.

CDC Reports on STECsCDC Reports on STECs

According to the US Centers for According to the US Centers for Disease Control and Prevention, non-Disease Control and Prevention, non-O157 E. coli STECs (like O26, O45, O157 E. coli STECs (like O26, O45, 0103, O111, O121, and O145) cause 0103, O111, O121, and O145) cause 36,700 illnesses, 1,100 hospitalizations 36,700 illnesses, 1,100 hospitalizations and 30 deaths in America each yearand 30 deaths in America each year

Top Non-O157 Serotypes Top Non-O157 Serotypes (CDC)(CDC)

O26O26 22% of non-O157 22% of non-O157 STECSTEC

O111O111 16% of non-O157 16% of non-O157 STECSTEC

O103O103 12% of non-O157 12% of non-O157 STECSTEC

O121 O121 9% of non-O157 STEC 9% of non-O157 STEC O45O45 7% of non-O157 7% of non-O157

STECSTEC O145O145 5% of non-O157 5% of non-O157

STECSTEC

Annual Submission of Non-O157 to Annual Submission of Non-O157 to PulseNet PulseNet

CDC

E. coli O157 vs. Non-O157 E. coli

Persons with non-O157 STEC Persons with non-O157 STEC USUALLY USUALLY have less severe illnesshave less severe illness

Non-O157 STEC include many Non-O157 STEC include many serogroups, with varying virulenceserogroups, with varying virulencesome typically cause only mild diarrheasome typically cause only mild diarrheaothers can cause HUS and deathothers can cause HUS and death

Non-O157 isolates predominantly have Non-O157 isolates predominantly have shiga toxin 1shiga toxin 1

Food commodities implicated Food commodities implicated outbreaks of non-O157 STEC outbreaks of non-O157 STEC

infections with known food commodity, infections with known food commodity, 1990-20071990-2007

Commodity Number outbreaks Food items

Fruit-nuts 3 Juice, apple cider, berries

Dairy 2 Cheese, margarine

Leafy vegetables 1 Lettuce

No outbreaks due to beef

But it all changed in 2010 with But it all changed in 2010 with the recall of ground beef the recall of ground beef because of human illness because of human illness

associated with O26 associated with O26 contaminationcontamination

Testing for STECTesting for STEC

E. coliE. coli O157 O157Unusual feature: does not ferment Unusual feature: does not ferment

sorbitolsorbitol

Non-O157 STECNon-O157 STECLack unusual featuresLack unusual featuresA group of organisms A group of organisms

USDA ApproachUSDA Approach

Top 6 serotypes Top 6 serotypes Responsible for about 70% of non-O157 Responsible for about 70% of non-O157

human illness.human illness. O26O26 22% of non-O157 STEC22% of non-O157 STEC O111O111 16% of non-O157 STEC16% of non-O157 STEC O103O103 12% of non-O157 STEC12% of non-O157 STEC O121 O121 9% of non-O157 STEC9% of non-O157 STEC O45O45 7% of non-O157 STEC 7% of non-O157 STEC O145O145 5% of non-O157 STEC 5% of non-O157 STEC

How Do Pathogens Find Their Way How Do Pathogens Find Their Way into Beef Supply?into Beef Supply?

Hide is the principal sources of these Hide is the principal sources of these pathogens. pathogens.

Inadequate dressing practices is Inadequate dressing practices is responsible for transferring generic and responsible for transferring generic and pathogenic bacteria from hides onto the pathogenic bacteria from hides onto the carcass.carcass.

Once on the carcass it is impossible to be Once on the carcass it is impossible to be 100% sure that you have eliminated them.100% sure that you have eliminated them.

The Ability to Detect PathogensThe Ability to Detect Pathogens

HidesHides

Carcass (right after hide is removed)Carcass (right after hide is removed)

Carcass (after all interventions)Carcass (after all interventions)

Trim Trim

Ground BeefGround Beef

Message: If it is on the carcasses after hide is removed, sooner or later it will be on the subprimals, trim and ground beef.

ControlControl

Hide is the principal source of mostHide is the principal source of most

pathogens. An effective control in order ofpathogens. An effective control in order of

significance is:significance is:11stst - Dressing practices - Dressing practices

22ndnd - Effective interventions - Effective interventionsEffective – scientific supportEffective – scientific supportWorks in your hands – validation Works in your hands – validation Must make contact the potential pathogensMust make contact the potential pathogens

33rdrd - Effective test and hold - Effective test and hold

Control of STECs Control of STECs

STEC are a natural part of the animal microflora.STEC are a natural part of the animal microflora.

Some Non-O157 STEC can cause severe disease in Some Non-O157 STEC can cause severe disease in humans.humans.

Non-O157 STEC is found at high frequency in pre-Non-O157 STEC is found at high frequency in pre-harvest samples (feces and hides).harvest samples (feces and hides).

Non-O157 STEC is probably just as prevalent, maybe Non-O157 STEC is probably just as prevalent, maybe more, than O157 STEC in pre-harvest samples.more, than O157 STEC in pre-harvest samples.

Interventions used at the processing plants affect Interventions used at the processing plants affect STECs similarly.STECs similarly.

HACCP Reassessment IssuesHACCP Reassessment Issues

Lack of information in incidence of Big 6 STECs Lack of information in incidence of Big 6 STECs in beefin beef

Lack of scientific documentation regarding Lack of scientific documentation regarding validation of interventions and their effect on Big validation of interventions and their effect on Big 6 STECs6 STECs

Questions about availability and relevancy of Questions about availability and relevancy of supplier COAssupplier COAs

Questions about trim testing and finished Questions about trim testing and finished product testingproduct testing

Test and Hold policy?Test and Hold policy?

HACCP Reassessment IssuesHACCP Reassessment Issues

According to the Federal Register Notice, According to the Federal Register Notice, USDA FSIS is assuming that the slaughter USDA FSIS is assuming that the slaughter and processing interventions, testing and processing interventions, testing programs and COAs in effect to address programs and COAs in effect to address E. coli E. coli O157:H7 will apply directly to the O157:H7 will apply directly to the Big 6 STECsBig 6 STECs

There are potential problems with COAs There are potential problems with COAs as they relate to non-E. coli O157:H7 as they relate to non-E. coli O157:H7 STECsSTECs

Problems in Conducting Problems in Conducting ReassessmentReassessment

Without extensive testing for the Without extensive testing for the Big 6 STECS – will the packers Big 6 STECS – will the packers be willing to issue COAs and if be willing to issue COAs and if they, will they be meaningful?they, will they be meaningful?

Problems in Conducting Problems in Conducting ReassessmentReassessment

Another problem will be how to provide Another problem will be how to provide scientific support for slaughter and processing scientific support for slaughter and processing interventionsinterventions

Many NAMP members use ambient Many NAMP members use ambient temperature control as a CCP for temperature control as a CCP for E. coli E. coli O157:H7 – There is a need for scientific O157:H7 – There is a need for scientific documentation specifically to address the Big documentation specifically to address the Big 6 STECs6 STECs

Problems in Conducting Problems in Conducting ReassessmentReassessment

US Beef Processors use processing US Beef Processors use processing interventions, including Sanova, organic interventions, including Sanova, organic acids and UV – USDA FSIS in the Federal acids and UV – USDA FSIS in the Federal Register assumes that interventions for Register assumes that interventions for controlling controlling E. coli E. coli O157:H7 will be effective O157:H7 will be effective for the Big 6 STECs – In order for HACCP for the Big 6 STECs – In order for HACCP plans to be valid, there should be real plans to be valid, there should be real scientific support for that assumption scientific support for that assumption

Interim Reassessment StepsInterim Reassessment Steps

1.1. Request updated COAs from suppliers to Request updated COAs from suppliers to address the Big 6 STECsaddress the Big 6 STECs

2. Assume all slaughter and processing 2. Assume all slaughter and processing interventions in place to address interventions in place to address E. coli E. coli O157:H7 O157:H7 are effective at controlling other STECsare effective at controlling other STECs

3. Conduct some level of testing for STECs in raw 3. Conduct some level of testing for STECs in raw materials and finished product to verify the materials and finished product to verify the effectiveness of HACCP planseffectiveness of HACCP plans

4. Continue to reassess and provide scientific 4. Continue to reassess and provide scientific documentation as it becomes availabledocumentation as it becomes available

USDA Testing of Trimmings USDA Testing of Trimmings for STECsfor STECs

USDA Testing for non-E. coli O157:H7 USDA Testing for non-E. coli O157:H7 STECs began earlier this monthSTECs began earlier this month

Expect about 4-10% of the sample to be Expect about 4-10% of the sample to be “potential positive” that is the enrichment is “potential positive” that is the enrichment is eae + stxeae + stx

Expect to have about 10 times the Expect to have about 10 times the prevalence of that of prevalence of that of E. coli E. coli O157:H7O157:H7

Effect on trim prices (tested negative and Effect on trim prices (tested negative and positive)positive)

Industry Initiative on nSTECsIndustry Initiative on nSTECs

Regardless of potential FSIS actions Regardless of potential FSIS actions on nSTECs, it is in the interest of the on nSTECs, it is in the interest of the beef industry to address the issue of beef industry to address the issue of nSTECs before it explodes into a nSTECs before it explodes into a major public health crisis. major public health crisis.

Scientific IssuesScientific Issues

Testing methods for the BIG 6 STECs are Testing methods for the BIG 6 STECs are available and will improve over timeavailable and will improve over time

USDA has funded research to answer USDA has funded research to answer many of the outstanding questions about many of the outstanding questions about the validity of slaughter and processing the validity of slaughter and processing interventionsinterventions

These studies will eventually provide the These studies will eventually provide the necessary scientific documentation to necessary scientific documentation to support HACCP planssupport HACCP plans

Long Term SolutionLong Term Solution

Interventions designed to virtually Interventions designed to virtually eliminate surface contamination on eliminate surface contamination on beef carcass - Carcass Pasteurizationbeef carcass - Carcass Pasteurization

Post-Chill UV/PhotohydroionizationPost-Chill UV/PhotohydroionizationStaged Antimicrobial TreatmentsStaged Antimicrobial TreatmentsThermal – Steam or Hot WaterThermal – Steam or Hot Water

The best outcome (sliver The best outcome (sliver lining) lining)

Renewed focus on dressing practices Renewed focus on dressing practices and process control.and process control.

Current E. coli O145 OutbreakCurrent E. coli O145 Outbreak

14 Confirmed cases in Southeastern US14 Confirmed cases in Southeastern US1 Death1 DeathAppear to be a sporadic outbreakAppear to be a sporadic outbreakSo far, the CDC has been unable to So far, the CDC has been unable to

identify the source of the outbreakidentify the source of the outbreakThis outbreak underscores the need to This outbreak underscores the need to

address Non-E. coli O157:H7 STECsaddress Non-E. coli O157:H7 STECs

Questions?Questions?