Prevention of Listeriosis
Outbreaks in a High-Risk
Food Service Setting
How can an RD help?
Presented by Anne Smith
What is Listeriosis?
 A foodborne illness caused by ingesting the bacteria Listeria
monocytogenes
 Gram-positive bacillus
 Found in water and soil, non-pasteurized milk and milk products,
and on contaminated vegetation
 Can also be found in infected animals who ingested the bacteria
 Cold-tolerant; can survive and replicate in temperatures below
40oF
 Can colonize on environmental surfaces
 Can easily be killed by heat
L. monocytogenes
Gram-positive bacillus
Who is at Risk?
 Pregnant women and the fetus
 Highest risk in third trimester
 Can cause spontaneous abortion
 Immunocompromised persons
 Malignancies
 Solid organ and bone marrow transplantations
 Immunosuppressive therapy- HIV infection and AIDS
 Neonates
 Older adults
 Kidney or liver disease
 Alcoholism
 Diabetic patients
Symptoms
 Febrile gastroenteritis
 Most common in healthy adults
 Mild, flu-like symptoms
 Fever, intense headaches, nausea, and vomiting
 Bacteremia and meningitis
 Most common in Immunocompromised
 Miscarriage, stillbirth, premature delivery, or lifethreatening infections in a newborn
 9%-30% can be fatal
What foods can be affected?
 Cold ready-to-eat foods not heated before consumption
 Delicatessen-style meats, hotdogs
 Cold-prepared salads such as tuna salad or egg salad
 Soft cheeses- feta, Brie, Camembert, blue-veined
cheeses, or Mexican-style cheeses such as queso
blanco, queso fresco and Panela
 Contaminated vegetables and animal products
 Risk increases for durations of refrigeration
CDC Reported Outbreaks
 2011- Listeriosis Linked to Whole Cantaloupes from
Jensen Farms, Colorado
 2012- Listeriosis Linked to Imported Ricotta Cheese
 2013- Listeriosis Linked to Crave Brother Farmstead
Cheese
 http://www.cdc.gov/listeria/outbreaks/index.html
Global Reported Outbreaks
 US- 175 cases reported in 3 years
 About 58/yr
 Globally in 2006
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France- 290
Germany- 508
UK- 208
Spain- 78
Czech Republic- 78
Netherlands- 64
Occurrences of Listeriosis in
Healthcare
 Fall 2003, UK
 5 pregnant women
 2 separate facilites
 Contaminated sandwiches
 February 2010, Texas
 10 cases in 7 months
 5 separate facilities
 Contaminated diced celery
 September 22, 2008, New York
 3 listeriosis cases at hospital X
 2 other cases identified later
 Contaminated tuna salad
How is it identified?
 Pulsed-field gel electrophoresis (PFGE) patterns
Our study
Serving High-Risk Foods in a
High-Risk Setting:
Survey of Hospital Food Service Practices after
an Outbreak of Listeriosis in a Hospital
Carolyn Cokes, MPH, Anne Marie France, PhD, Vasudha Reddy, MPH,
Heather Hanson, MPH, Lillian Lee, MS, Laura Kornstein, PhD, Faina
Stavinsky, MS, Sharon Balter, MD
Purpose
“This report summarizes the outbreak
investigation for Listeriosis in a NYC hospital as
well as the results of a telephone survey of
NYC hospitals that explored risk management
practices for foodborne illnesses in hospital
settings.”
5 cases of Listeriosis were reported from Hospital
X in New York
Subjects
 4 male, 1 female
 Median age was 62 years (range 52-92 yo)
 All had medical conditions that put them at high-risk of
Listeriosis
 Complications from transplanted liver
 Chiari syndrome
 Chronic heart failure
 Mitral valve disorder
Methods
 5 Methods of Investigation
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Epidemiologic Investigation
Environmental Investigation
Laboratory Investigation
Hospital Survey
Statistical Methods
Epidemiologic Investigation
 Medical record abstractions
 Patient interviews
 Onset dates
 Clinical illness
 Food history
 Menus from hospital cafeteria
 Reports posted to identify other related Listeriosis cases
 CDC’s Epi-X communication site
 PulseNet CDC Team electronic bulletin board
Environmental Investigation
 9/23/08-Full sanitary inspection- NYC OEI
 Swabs of food-contact surfaces
 9/25/08- HACCP analysis based on prep reviews
 Tuna salad and turkey sandwiches
 9/29/08- Samples collected
 Environmental surface samples for Listerosis analysis
 9/30/08 and 10/3/08- More samples
 25 samples from cooking/storage surfaces, kitchen equipment,
vents, drains, and floors
 20 food samples- tuna, chicken, and egg salad
Laboratory Investigation
 Clinical isolates from NYC cases submitted to PHL for
analysis
 All samples were analyzed for PFGE patterns
 L. monocytogenes DNA was restricted using 2
enzymes
 Ascl and Apal
 Gels were uploaded to PulseNet for identification of
related cases
Hospital Survey
61 acute care hospitals in NYC were asked to participate in
a telephone survey, 54 responded
January-April 2009
Section 1
Section 2
Director of Infection Control
Food Service Director
 Prevalence of high-risk
patients in comparison to
total patients
 Units available for high risk
patients
 Focus on foods served
 Food service practices and
policies
 Policies restricting service of
items that present high risk
Statistical Methods
 SAS software, version 9.1
 SAS Institute
 P values
 2-sided
 Calculated by Fisher exact test, x2 analysis or t test
Epidemiologic Results
 Food histories
 Pts 1-3 obtained by direct interview
 Pt 4- no history, patient died
 Pt 5- partial history from next of kin
 Common foods- Tuna salad and sliced turkey
 Pts 1-3- reported having both
 Pt 5- most likely consumed both
 Hospital did not keep copies of food orders
 None of the 5 patients have been in rooms on the same
floor at the same time
Laboratory Results
 Contaminated samples
 4 samples of tuna salad
 1 can-opener sample
 1 floor drain sample
 All 5 human isolates contained L. monocytogenes
 No similar PFGE patterns were in PulseNet
PFGE
Environmental Results
 Inspections showed no violations of NYC health codes
 HACCP investigation showed tuna was held at 41oF for
4 days before being served
 2 environmental samples contained L. monocytogenes
 Can opener base- opened the cans
 Floor drain- located near 100 qt mixer
 October 2009- all negative samples
Survey Results
 9 were public hospitals, 45 were private hospitals
 23 reported maintaining patient food orders
 8 kept records with patient charts
 29 reported outside food vendor contracts
Food Safety Practices
"Despite the potential for severe outcomes of Listeria
infection among hospitalized patients, the majority of
NYC hospitals that participated in the food practice
survey had no food preparation policies or practices to
minimize risk for L. monocytogenes contamination."
Foodborne Illness Risk
Management Guidelines
Reported Raw fruits and vegetable use
•62% of Large hospitals reported not using raw F&V
•Facilities with transplant pts less likely to report use of raw F&V
•75% with bone marrow transplant units
•100% with organ transplant units
Helpful Policies
From the study:
 Steam deli meats before serving
 Do not serve soft cheeses
 Use only cooked (irradiated) F&V components
Other Suggestions:
 Severely limit storage time of high-risk foods
 Keep better food records for healthcare providers
 Routine and thorough cleaning of food surfaces
 Keep records of patient food orders and diet history
 Test strips?
 Contract out food service?
Role of the RD
 Menu planning
 Food purchasing planning, budgeting, and source
approval
 Education of food service workers on food safety
 Daily/weekly dietary assessments of high-risk patients
 Eurosurveillance- improve procedures
 Computer system to track orders
Global Food Safety
 Global Food Safety Initiative
 Manufacturers
 ServSafe certifications
 Costly?
 Australia’s Food Safety Guidelines
 Safer food alternatives
 Food Standards Agency –UK
 Video learning
Comments
 Stacy- “Do you think it is the role of the RD or DTR to
monitor patient charts to prevent them from receiving
potentially dangerous foods? Listeria outbreaks are
preventable with proper food safety practices, so do
you believe better training of kitchen staff is more
important than monitoring food ordered?”
 Liz- “A computer based diet record and food ordering
system should have flags that prevent at-risk persons
of ordering risky items off the menu. I know its possible
to flag for such things as a "heart healthy diet" or
"diabetic diet", why not create another category for "atrisk".
Other Comments?
References

Cokes, Carolyn, MPH, Anne Marie France, PhD, Vasudha Reddy, MPH, Heather Hanson, MPH, Lillian Lee,
MS, Laura Kornstein, PhD, Faina Stavinsky, MS, Sharon Balter, MD. “Serving High-Risk Foods in a High-Risk
Setting: Survey of Hospital Food Service Practices after an Outbreak of Listeriosis in a Hospital.” Infection
Control and Hospital Epidemiology. April 2011. Vol 32 No 4

Denny, Justin, Jim McLauchlin. “Human Listeria monocytogenes infections in Europe - an opportunity for
improved European surveillance.” EUROSURVEILLANCE Vol. 13 · Issues 1–3 · Jan–Mar 2008.

http://www.health.ny.gov/diseases/communicable/listeriosis/fact_sheet.htm. Accessed online September 5,
2013.

http://www.cdc.gov/listeria/index.html. Accessed online September 5, 2013.

Dawson, SJ, MR Evans, D Willby, J Bardwell, N Chamberlain, DA Lewis. “Listeria outbreak associated with
sandwich consumption from a hospital retail shop, United Kingdom.” Eurosurveillance, Volume 11, Issue 6, 01
June 2006.

Gaul, Linda Knudson, Noha Farag, Trudi Shim, Monica Kingsley, Benjamin Silk, Eija Hyytia-Trees. “HospitalAcquired Listeriosis Outbreak Caused by Contaminated Diced Celery—Texas, 2010”. Clin Infect Dis. (2013) 56
(1): 20-26

http://www.food.gov.uk/. Accessed online September 9, 2013.

http://www.health.sa.gov.au/pehs/food-index.htm. Accessed online September 9, 2013.