Investigation of a Salmonella Thompson Outbreak at a Local London Restaurant

Overview• Background Information• The investigation process:

Information gathering: Case interviews, premise follow-up/ investigation, team meetings and food samples.

• Collaboration with partner agencies

• Risk Assessment: decisions made• Lessons Learned

Background Information• MLHU Outbreak response team: PHN (Joanne Dow),

Outbreak lead PHI (Carrie Warring) and District PHI (Randy Walker); managers David Pavletic and Tristan Squire-Smith.

IDC

Outbreak Lead

District PHI

Other PHI’s

Managers Directors/MOH

Background Information• S. Thompson common sources: beef, bread,

chicken, cilantro, eggs, lettuce, peanuts, pet treats, potato salad, roast beef, salmon, tomatoes (PHO, 2014).

• Middlesex-London investigated a sub-cluster of 19 outbreak confirmed cases

• 15 cases reported eating at the same restaurant in London

• Two cases from Oxford also ate at same restaurant

National and Provincial• Public Health Agency of

Canada (PHAC) created the OICC on July 2nd 2014

• National cases (75, expect 14)

• Public Health Ontario ON-OICC initiated on August 12, 2014

• Ontario cases (51, expect 9)• As of August 16th, 2014• OICC- Outbreak

investigation coordinating committee

Timeline

Case Interviews• Joanne Dow• Single interviewer• Provides “memo” regarding suspect

exposures• Collaborates with Outbreak Lead• Information sharing with Public Health Ontario

(PHO)

Local Restaurant• Located downtown

London, Ontario• No special events

during incubation (Victoria Park)

• Very popular: high volume of customers

• Mediterranean food items: Shawarma, Falafel, Salads etc

Investigation • 2 Cases reported on July 16th 2014• Then, 7 Cases reported on Friday July

25th (5 pending). • Only 2 cases report the Shawarma

food premise• PHO/PHAC shift focus to grocery store

food items (national/provincial outbreak)

• Recalls: paprika and pepper for Salmonella

Investigation• 5 suspect food premises (2 cases for the

Shawarma restaurant)• PHI’s asked to complete investigations at all

implicated premises • In addition: document ingredients used

(spices), product source (name, supplier, lot codes etc)

• Changes to recipes, ingredients or suppliers• HACCP audits• Staff illness / other complaints

Food Samples• July 31st 2014• Red Cabbage• Oregano• Parsley S. Thompson• ½ Shawarma• ½ Mala Salad• Aug. 1 (7 exposures)

Parsley?• CFIA follow up: • Perishable food item

(fresh product)• Typically not cooked• Common ingredient • High turnover• Difficult to trace• Distribution

(national/ provincial ?)

• Increase in cases?

Outbreak Team Meeting• Management• Outbreak Lead• IDC PHN• District PHI/ PHI’s• Food Chart created

to distinguish ingredients

• Chicken most common

• Submit 2 chicken samples

Food Samples• Obtained food samples (raw chicken and

marinated raw chicken)• Then 2 chicken suppliers discovered (CFIA,

OMAFRA)• Determined frequency of delivery• Information provided to PHO, OMAFRA and

CFIA (also investigating parsley)• Raw chicken samples submitted: one from

each supplier• Results?

Salmonella Detected

Update• Salmonella detected in:• chopped parsley, oregano, raw chicken and

marinated raw chicken. • E.coli found in Hummus• Not detected in raw chicken samples

submitted from each supplier• Parsley S. Thompson only• Investigation focused on parsley, cross

contamination, hand washing, product discarded (put on hold), and cleaning/ sanitizing

Partner Agencies• Public Health Agency of Canada• Public Health Ontario• The Canadian Food Inspection

Agency• Ontario Ministry of Agriculture,

Food and Rural Affairs• Public Health Lab

Risk Assessments• Premise closure?• Media disclosure?• Food premise cooperation,

frequency of district inspector visiting premise, lag in time, ill food handlers(?)

Lessons Learned• Team work: Sharing ideas and

open discussion• Collaboration of IDC PHN and

Outbreak Lead• Information sharing with partner

agencies• Document EVERYTHING

Thank You!

References• Public Health Agency of Canada (2014). National

Enteric Surveillance Program: Weekly report. Week 2014-33. Aug. 10-16, 2014.

• Public Health Ontario (2014). Ontario Investigation Summary: Salmonella Thompson. Updated Oct. 1, 2015

• Public Health Ontario (2014). Ontario Salmonellosis Investigation Tool: Appendix 2 Source attribution of the common Salmonella serovars. Aug. 2014

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