Anatomy of an Outbreak: An Outbreak of Salmonella Javiana

Associated with Food TrucksElizabeth Traphagen, MPH

EpidemiologistEpidemiology Program

MA Dept. of Public Health

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Overview• Foodborne illness surveillance:

– History and trends• National• Massachusetts

– Outbreaks• WGFIC, PulseNet

• The role of the laboratory– ELR, isolate submission

• Outbreak Investigations– Case study

Factors that Influence the Emergence of Foodborne Illness

• Microbial adaptation– Increased virulence– Antibiotic resistance – Example: Salmonella DT-104

• Global trade– Contact with unfamiliar

pathogens– Example: Raspberries from

Guatemala• International travel

– Dramatic increases in 20th century

– Infection by uncommon pathogens

– Examples: Typhoid fever and cholera

• Food industry demographics– Increased market size– Centralized food processing – Low dose, widely distributed

outbreaks– Example: Shigella in parsley,

salmonella in peanut butter, E. coli O157:H7 in raw cookie dough

• Immigration– Traditional practices– Customs, language, social

barriers– Example: salmonella from live

bird markets

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Additional Emergence Factors:

• What people eat– Changes in food preferences– Fresh fruits and vegetables – “Organic”– Undercooked foods– Example: E.coli in “grass fed

cattle”• Where people eat

– Fast foods and salad bars

• Social demographics– Increased life expectancy– Chronic disease survivors– Increased susceptibility to

enteric pathogens– Example: Listeria in the

elderly• Food preparation skills

– Few opportunities for home instruction

– No “Home-Ec” in schools– Foodborne illness in the

home

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Recent Multi-state Outbreaks

Bug Food Year

Salmonella heidelberg Foster Farms Chicken 2013

Vibrio parahaemolyticus Raw Shellfish 2013

Cyclospora Fresh Produce 2013

Listeria monocytogenes Commercially produced Caramel Apples

2014

Salmonella enteritidis Bean Sprouts 2014

Salmonella (Newport, et al)

Organic Sprouted Chia Powder 2014

Listeria monocytogenes Blue Bell Ice Cream 2015

Salmonella poona Cucumbers 2015

Salmonella enteritidis Raw, Frozen, Stuffed Chicken Entrees 2015

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Trends in Foodborne Outbreaks in Massachusetts

• We are still seeing “event” driven outbreaks– Weddings, birthday parties, potluck dinners– Why?

• But we are also seeing more and more nationwide outbreaks– Peanut butter, raw cookie dough, veggie booty, spinach,

parsley, orange juice, pet food, etc.– Why?

Enteric Diseases in MA:Confirmed Cases per Year

  2009 2010 2011 2012 2013

Amebiasis 44 39 33 25 27

Botulism 0 1 1 1 1

Calicivirus 104 93 86 279 217

Campylobacteriosis 1136 1085 1306 1350 1601

Clostridium perfringens 7 0 1 3 2

Cryptosporidiosis 182 172 166 156 123

Cyclosporiasis 7 15 2 1 5

Giardiasis 759 745 749 707 674

Hepatitis A 70 50 40 40 44

Listeriosis 34 27 32 27 26

Salmonellosis 1164 1246 1063 1051 1169

Shiga-toxin producing organism 82 63 68 78 109

Shigellosis 245 213 172 132 177

Vibrio species 60 53 51 72 105

Yersiniosis 31 33 32 35 22

* Data as of 20JUNE2014 and are subject to change.

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STEC, Salmonella and Campylobacter in MA

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Vibrio parahaemolyticus in MA

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Salmonella Seasonality in MA

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• Food Protection Program• MDPH Epidemiologists• Enteric lab• PFGE lab• Local Boards of Health (LBOHs)

Who are the players involved in surveillance and outbreak investigation in MA?

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• Passive surveillance (state and local)– Over 15 enteric diseases are reportable to the state and local health

departments in Massachusetts and every other state

• FoodNet (national)– Surveillance for E. coli O157:H7, Campy, Listeria, Salmonella, Shigella,

Yersinia, Vibrio, Cryptosporidium and Cyclospora

• PulseNet (national)– Database with DNA "fingerprints"

• NARMS (national)– National antimicrobial resistance monitoring system

• NORS (national)– National outbreak reporting system

Foodborne Disease Surveillance in MA

Population exposed

Person becomes ill

Person seeks care

Specimen obtained

Lab tests for pathogen

Pathogen isolated

Reported to health departmentPyramid of surveillance

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Limitations to surveillance and investigation…

• Illnesses are not reported - by consumers or healthcare• Healthcare doesn't test • When tests are done, isolates are not sent to public health

laboratories for further testing• The process of illness to testing to reporting to

investigation is too long• People don't remember what they ate

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Delays in Recognition

• Day 1: undercooked hamburger consumed• Day 5: bloody diarrhea begins and a decision is made that it must

have been what was eaten the night before (on day 4)• Day 6-8: still sick• Day 9: seen by HCP, stool sent to lab• Day 10:

– positive for E. coli O157:H7– reported to public health & specimen sent to public health laboratory

• Day 11: patient contacted and asked for food history; patient reports what they ate on day 4

• Day 13: PFGE results available & posted to PulseNet

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Typical incubation periodsTypical incubation periods

• Salmonella 12-36 hours

• Shiga Toxin + 10 hrs-10 days

• Norovirus 1-2 days• Shigella 1-3 days• Campylobacter 2-5 days

• E. coli O157:H7 3-4 days• Yersinia 3-7 days

• Cryptosporidium 7days• Cyclospora 7 days• Amebiasis 1-4

weeks• Giardia 7-10 days• Listeria > 14 days

• Trichinella > 14 days

• Hepatitis A and E > 14 days• Brucella > 30 days

Outbreaks

• Definition: occurrence of disease greater than what would be expected at a particular place and time

• Notification:– Surveillance– Foodborne illness complaints– Lab-based surveillance– Phone calls

17MA PHIT- Food Certificate Program, Day 4, Session 3

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CSI: The Public Health Laboratory

• The past– Genus– Species– Serotyping/serogrouping

• The present– DNA testing

• PFGE testing, PCR, MLVA

• The future (?)– Culture Independent Diagnostic Testing (CIDT)– Next Generation Sequencing (NGS)

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PFGE Patterns

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PulseNet

• Is an electronic database of "DNA fingerprints" identified at local, state or federal laboratories

• Was created as a result of the E. coli outbreak• Plays a vital role in surveillance and the investigation of foodborne

outbreaks• Is instrumental in the identification and resolution of outbreaks

where the cases are geographically dispersed• Allows for outbreaks to be identified in hours rather than days or

even weeks• Next Generation-CIDT

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July Sun Mon Tue Wed Thu Fri Sat

1 2 3 4 5 6

7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23 24 25 26 27

28 29 30 31

Phases of the moon: 8: 15: 22: 29: Holidays and Observances: 4: Independence Day

PFGE lab reported 10 matching isolates of Salmonella Javiana.

A Case Study: Summer of 2013

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• Causes over one million illnesses in the US– 19,000 hospitalizations– 400 deaths

• Incubation period is 6 to 72 hours

• Symptoms include diarrhea, fever, abdominal cramps and vomiting

• Duration of illness is 4 to 7 days

Salmonella

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• 4 MA counties• 20-65 years old• Specimen dates 7/2-7/6

– Onset dates end of June• Pattern last seen in MA in 2011• No national matches

The First Cases:

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• MDPH Epidemiologists and LBOHs began interviewing initial cases– First 4 interviewed all reported eating at a food

truck or restaurant owned by Company A

Initial investigation

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Food Trucks

• From Roach Coach to Cultural Phenomena• Low marketing and operational costs• Chefs laud as more rewarding and financially

feasible than brick and mortar

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Problems common to most food trucks

• Cold holding is a major issue– Small fridges cannot maintain proper temps– Re-supply vans have similar issues

• Cross contamination– Processing in a small area

• Adequate water supply– Handwashing, cleaning

• Location of bathrooms• Leftover food disposition

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Company A

4 restaurants:CambridgeBrookline*Burlington*

*Opened week of 6/23/13

8-9 food truck locations:CambridgeBostonBrookline

Commissary:Food preparation

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• Food trucks loaded at commissary every morning

• Re-stocking vans deliver food to restaurants and food trucks throughout the day

• Leftover food returned to commissary and re-used

Daily operations

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Initial investigation continuedJuly

Sun Mon Tue Wed Thu Fri Sat 1 2 3 4 5 6

7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23 24 25 26 27

28 29 30 31

Phases of the moon: 8: 15: 22: 29: Holidays and Observances: 4: Independence Day

By 7/12/13, 12 cases had been identified.

7 interviewed: all had eaten at a restaurant or food truck owned by Company A

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Common foods among cases

• Chickpea fritters• Egg and eggplant sandwiches• Hummus• Various side dishes• No one food item in common

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Commissary inspection 7/12/13

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• LBOH performed unannounced inspection of commissary on July 12, 2013

• All operations ceased

Inspection

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– Environmental swabs– Collected raw food for testing– Performed inspections of food trucks with LBOH– Tried to obtain Standard Operating Procedures– Initiated licensing for commissary

Next steps: Food Protection Program

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Next steps: Epidemiologists

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– Coordinated specimen testing for employees• Two negative stool tests > 24 hours apart• Enteric lab performed testing

– Obtained employee log and illness policy– Cleared employees – Analyzed data

Next steps: Epidemiologists

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– Continued interviewing cases– Assisted with specimen collection– Followed up with positive foodhandlers in their

towns– Inspected Company A’s stores and food trucks

Next steps: LBOHs

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Next steps: Company A

• The day they were notified of their connection to the outbreak, the company owner starting blogging on their website.

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The “posts”• The daily blogs started on 7/13• The owner talked about every step of the

investigation, over and over again and even discussed employee test results

• Went through every hypothesis and discounted them– “We think it UNLIKELY it was introduced by our food

handlers as they follow safe practices. They wash their hands after breaks/ eating/ bathroom/ between tasks/ when changing gloves.”

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… the "responses"• “With these posts, you’re a model of grace under pressure. I

look forward to my next meal after you guys are back up and running”

• “You continue to amaze me with your standard of doing the right thing.”

• “You guys are amazing. Thank you so much for being so transparent and honest with all of this.”

• “I’m a loyal customer and so sad to hear about what you’re going through.”

• “Fate has called your bluff here, but you’re walking the walk.”

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• Food trucks– Ran out of water– Food out of temperature and reused

• Heat wave at end of June

– Re-supply van not chilled to proper temperature– Inadequate recording of temperatures – A general lack of appropriate SOPs

Results: Food truck inspections

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• No environmental swabs tested positive for Salmonella Javiana

• No food specimens tested positive for Salmonella Javiana

Results: Testing

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• 11 employees tested positive for Salmonella Javiana– Matched to cases by PFGE– 1 employee also tested positive for Salmonella

Newport– Only 3 positive foodhandlers reported symptoms

Results: Testing

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• Poorly defined illness policy• Sick log showed workers with bloody diarrhea

and vomiting returning to work too soon• A lot of new hires in June

Illness policy and employee log

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Final case tally

• 18 consumers – 17 linked to Company A

• 3 restaurants, 3 trucks– 1 consumer ate at a restaurant next door to one

of the implicated restaurants

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Case Distribution Among Stores and Trucks

Store AStore B

Store CStore D

KitchenTruck 1

Truck 2Truck 3

Other

0

2

4

6

8

10

12

14

FoodworkersConsumers

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Epi Curve/Onset Dates

N=21

0

1

2

3

4

5

6

7

8

6/25/20

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6/26/20

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6/27/20

13

6/28/20

13

6/30/20

13

7/4/201

3

7/7/201

3

7/8/201

3

After 7/8

/2013

Foodhandlers

Cases

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• Breakdown in processes contributed to outbreak– Possibly due to opening of 2 new stores in one

week– A lot of new hires– Ill employees not kept out long enough, or tested– Inadequate cooling mechanisms– Improper sanitation/hygiene– Heat wave

Conclusions

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What was different about this investigation?

• Food trucks are very popular both with consumers and politicians

• The owner went public from the day of closing until they re-opened– Was this good or bad, did it help or hurt?– How did it affect the investigation?

• The outbreak involved the state and 4 different local jurisdictions

• The outbreak highlighted gaps in permitting. When does a retail operation turn into a food processing facility and who keeps watch?

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• Reopened after ~2 weeks• Hired a food safety consultant• Improved illness policy• Created SOPs• Obtained wholesale license• Purchased better supplies to keep food at

proper temperature

Final remarks

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A big thank you to:

• Working Group on Foodborne Illness Control• Local Boards of Health

– Boston– Brookline– Burlington– Cambridge

Thanks

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Questions?

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