Outbreak Investigations of Foodborne Illness

Sherri A. McGarryU.S. Food and Drug Administration

Center for Food Safety & Applied NutritionOffice of Food Defense, Communication &

Emergency Response

FDA & USDA:Which agency regulates these products?

Vegetables Seafood Chicken Dietary supplements Infant formula Frozen pizza with extra

pepperoni

USDA FDA √ √

√ √ √

√

FDA regulates foods (except meat, poultry, and some egg products), food and color additives, cosmetics, dietary supplements, infant formula

Outbreaks– FDA regulated products

1996 – 2008: Dairy 21 Eggs 207 Proc Foods 37 Produce 77 Seafood 114 Sprouts 27

Illnesses – FDA regulated foods

1996-2008: Dairy 349 Eggs 6609 Proc Foods 3684 Produce >9000 Seafood 2819 Sprouts 1633

Fresh Produce Outbreaks

Tomatoes Salmonella Leafy Greens E. coli O157 Cantaloupe Salmonella Hot peppers Salmonella Herbs Cyclospora, E. coli O157, Shigella

Raspberries Cyclospora Green Onions Hepatitis A Mango Salmonella

FDA’s Role inOutbreak Investigations

Investigation and coordination in multi-state outbreaks Review epidemiological, laboratory, and environmental

data Tracebacks of implicated foods Farm investigations Removal of implicated products from commerce Alert consumers Lab assistance Evaluate data to identify trends and develop policy,

guidance, and/or regulations to prevent future outbreaks

Requires teamwork!

Teamwork among scientists

Types of scientists needed: Microbiologists Laboratory scientists Epidemiologists Environmental sanitarians Veterinarians Food technologists Toxicologists Others – physicians, biologists, agriculturists, etc.

Anatomy of an Outbreak investigation

Disease Surveillance

Epidemiological investigation

Laboratory Analysis

Environmental investigation

Traceback / traceforward

Farm / Processor investigation

1. Disease Surveillance Why do we conduct surveillance of disease and

investigate outbreaks? Identify illnesses and potential outbreaks Prevent additional illnesses Identify causes to prevent future illnesses and outbreaks

Who is involved in surveillance? Federal agencies – CDC, FDA, USDA, EPA Laboratories Local and state public health departments

Science at work → Epidemiologists, Physicians, Public Health Officials, Veterinarians, Lab scientists

Surveillance and Reporting

Illness exposures in the general population

Person becomes ill

Person seeks medical care/reports illness to HD

Specimen obtained

Lab tests for pathogen

Culture confirmed case

Illness reported to

HD and CDC

How are multi-state foodborne outbreaks recognized?

Electronic Foodborne Outbreak

Reporting System(eFORS)

Database of reports of foodborne disease

outbreaks submitted through the internet by local or state health departments

PulseNet

Database of molecular subtyping

(or “fingerprinting”) of bacteria by

pulsed-field gel electrophoresis (PFGE) submitted by a national network of laboratories

Why does it take so long?

2. Epidemiological investigation

State and local public health officials – collect case information and evaluating data

Determine epidemiologic associations Case interview information Attack rates of illness by food type Test hypothesis → case control study

Interpreting statistical significance Implicate the food causing illness

3. Laboratory Analysis

Lab testing Clinical samples Food samples Environmental samples

Match clinical results to food product and/or environmental results

Science at work → Microbiologists, Chemists, Toxicologists, Lab scientists

Detecting outbreaks

Lab tools Standard methods to detect pathogens National database and historical patterns

PFGE PHLIS – Public Health Laboratory Information

System Electronic reporting system for Salmonella and Shigella

human isolates statistical algorithm designed to detect unusual clusters of

isolates of Salmonella infection

Detecting outbreaks - Lab

Lab associations Clustering in time of cases Same genus and species Same DNA fingerprint

Between cases and between cases and food Unusual spikes in illness

4. Environmental investigation

Best case scenario: The epidemiologic investigation helps guide the

environmental investigation including areas to focus collection and testing of environmental/product samples

However…. Product samples may no longer be available Changes likely have occurred in environment

Science at work → Environmental Sanitarians, Epidemiologists, Food technologists, Microbiologists

Environmental investigation

• State and local response:– Food preparation

review– Interview food workers– Determine if time,

temperature abuse or cross-contamination occurred

– Collect samples– Collect records

• Federal response:– Traceback (records)

– Source investigations along the distribution chain

• Determine if contamination occurred at that point

• Collect samples• Identify common source

5. Traceback

Epi and/or lab evidence implicates a food

Track food item back through the distribution chain to a common source

Investigate

Date Invoice #

5/5/08 89000SECTION QTY PACK SIZE DESCRIPTION

615444 6 50 50# Yellow Onion Med 050#602588 6 50 50# White Onion Med 050#645879 2 16 3# Bag White Onion 016@648055 1 10 10# Oragne Hbanero 010#648044 10 25 25# Tomato Bulk 6X6 LG692000 1 12 32OZ Mini Bag Red Potato 012@

Date: Invoice #:

5/5/2008 38947

Section QTY. Pack Size Description Code

454681 100 25 25# Tomato Bulk 6x6 LG 501785

DATE

CUSTOMER ID

SHIP TO BILL TO

Pallet No Size

2200 4X5

2289 4X5

2226 4X5

4452 4X5

2233 4X5

2698 4X5

2896 4X5

88 / 2144 / Beefsteak Tomato

88 / 2144 / Beefsteak Tomato

ORDER NUMBER

345115/ 3/ 08

Cartons / Manifest / Product

88 / 2144 / Beefsteak Tomato

88 / 6144 / Beefsteak Tomato

SHIP DATE

5/ 3/ 2008

88 / 2186 / Beefsteak Tomato

88 / 2144 / Beefsteak Tomato

88 / 2144 / Beefsteak Tomato

ORDER DATE

The Restaurant

May, 4 2008

[ABC12345]

22 Loveapple Way

Toma, TO 00001

The Restaurant

Foodtown, USA

301-555-5923

8 Gourmet Lane 8 Gourmet Lane

Foodtown, USA

301-555-5923

Shipping Report

Tomato Distribution Company

Please contact Customer Service at [Phone] with any questions or comments.

THANK YOU FOR YOUR BUSINESS!

Invoice

No. 92601985 Fruitplant Avenue To:

Pick, EM 00005 Tomato Distribution Co.22 Loveapple Way

Date: April 20, 2008 Toma, TO 00001

Quantity Description

500 Box, Greenhouse Tomatoes, Size '35'

Order # 4421

Pallet No

3300 100 Beefsteak Tomato3374 100 Beefsteak Tomato3380 100 Beefsteak Tomato3467 100 Beefsteak Tomato

Cases / Product

Pallets Boxes Size

1 88 (88) 5*5,3

2 88 (88) 5*5,3

3 88 (88) 5*5,3

4 72 (72) 5*5,3

5 88 (88) 5*5,3

6 88 (88) 5*5,3

7 88 (88) 5*5,3

. 8506

ORDER NUMBER

Whole Tomato

Whole Tomato

Whole Tomato

Whole Tomato

Product

Whole Tomato

Whole Tomato

Whole Tomato

Shipper: Fruit Haulers R UsConsignee: Fruit Growers, Co. 1985 Fruitplant Ave. Pick, EM 00005

Shipment Date 04/25/2008DestinationEst. Arrival 04/25/2008Pallet count 7

6. Farm investigation

Zoonotic Salmonella E. coli O157:H7 Campylobacter

Human Shigella Hepatitis A virus Norovirus Cyclospora

Know your pathogen!

Sources of Contamination

Multiple modes: Soil Water Workers Animals

Science at work → Water Specialists, Agriculturists, Wildlife Experts, Microbiologists

Everything is

connected!

FARM INVESTIGATIONS

Potential Sources of Contamination:

Ponds

Worker HygieneEquipment

Animals

Reality Check

Seldom do we find the “smoking gun”

Why not?A. Delay between when the outbreak was

detected and when consumers ate the contaminated food

B. Conditions at the source are not the same as when contamination occurred

C. Finding the pathogen is difficult

D. All of the above

Case Study…

Be the Detective!

Contamination at the Farm:

Salmonella SaintpaulSpring/Summer 2008

Early Sequence of Events

Late May - CDC gave FDA an early alert of Salmonella Saintpaul illnesses in NM & TX tomatoes a likely vehicle

CDC notifies FDA that tomatoes implicated FDA initiates traceback investigation June 3 – Consumer advisory for NM & TX –

raw red round and roma/plum tomatoes

What to Trace?

Select geographically diverse to triangulate Prefer cluster vs sporadic case traceback No clusters so select cases with the best:

Exposure info, receipts to document dates, good food historians, etc

FDA and CDC collaborate to identify best cases to trace

Traceability Challenges Lack of rapid connectivity Lack of unique identifier Repacking Co-mingling Addresses, ship and reciept dates Packaging (ie. cases) gone Produce no longer available Producing states importing as well

Sequence of Events - distribution

Intelligence gathering: Early outreach to industry on distribution patterns Industry provides general harvest info USDA, academic, FDA imports data

Epi suggests consumers nationwide at risk Early traceback info support

June 7 - Consumer advisory expanded from NM and TX to nationwide not to eat raw red

round and roma/plum tomatoes

Findings…

Tomatoes shipped from FL to Idaho Transportation costs may not be as much of a

factor as originally thought Transition time for harvest Key production areas - FL and MX Tomatoes in high demand, quick turnaround,

unusual market and distribution patterns

Responding to an Evolving Picture

No single common convergence on tomato traceback – Florida and Mexico Several firms appear more than once Are the problems with traceability making it impossible to

find the convergence?

Indications, but no statistical association of other ingredients causing illness

Comparing ingredients of suspect menu items among clusters Tough to trace guacamole and salsa

Stepped Up FDA Actions

Tomato farm investigations – FL & MX

Increased border sampling of multiple produce items

Cilantro, tomatoes, peppers, basil

Sampling assignment covering all points in the chain

Activation of FERN, state assistance for testing

Is it tomatoes?More than on vehicle?

MN finds statistical association with jalapeno pepper

FDA initiates pepper & Serrano tracebacks FDA & CDC face-to-face collaboration at

Emergency Operations Centers FDA outreach to industry for pepper harvest info,

geographic, distribution info, production and packing practices

FDA Pepper Product Investigations

Initiate hot pepper traceback

Initial traceback lead only to Mexico

FDA investigation team sent to MX

More pieces of the puzzle

Investigations find issues at multiple points in distribution chain in MX

June 21 - Positive jalapeno sample of outbreak strain collected at distribution center in McAllen, TX

IMPORT ALERT #99-23, "DETENTION WITHOUT PHYSICAL EXAMINATION OF RAW FRESH FRUITS AND VEGETABLES FROM LISTED MANUFACTURERS, SHIPPERS, AND/OR GROWERS DUE TO THE PRESENCE OF PATHOGENIC CONTAMINATION", ATTACHMENT - 7/30/08

• Posted on FDA’s website

FDA IMPORT ALERTSFDA IMPORT ALERTS

Due to the presence of Due to the presence of SalmonellaSalmonella

Some Figures…

• 447 Investigations by FDA and State Partners

• 244 Firms visited for traceback investigations

• Over 30 FDA field assignments Samples – Product and environmental Distributors, repackers, packing, farms

FDA teams in MX: 11 investigations

FDA: 482 total samples (sample = multiple subs not one)

34 Salmonella positive3 Salmonella Saintpaul matches

FERN: 199 total samples13 Salmonella positive 1 Salmonella Saintpaul not match

SAMPLE RESULTS AS OF 8/5/08

Stayed tuned for Peppers...

Lessons Learned

Lessons learned in all areas: Communication Response Investigations epi Intactions among state and feds Value of increased environmental sampling

Implemented in recent outbreaks

Conclusions

Science plays a major role in detecting outbreaks and investigating the source of contamination in foodborne outbreaks

Understanding how contamination occurred is critical in developing measures to minimize ongoing outbreaks and prevent future ones

Consumers, government, academia, and industry all play a vital role in protecting public health

Resources

www.fda.gov Bad bug book, food safety, press releases on

outbreaks, education, and more

www.cdc.gov PulseNet, surveillance, pathogens, education,

and more

www.foodsafety.gov