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Salmonella enterica serotype I 4,[5],12:i:- Illness Outbreaks Associated with Pork

Products, 2015-2016

After-Action Review Report 2015-18/2016-13

October 26, 2017

Overview

During 2015-2016, the Washington State Department of Health (WADOH), the Centers for Disease Control and Prevention (CDC), and FSIS

investigated two outbreaks of Salmonella I 4,[5],12:i:- infections linked to pork products produced by Establishment A, a federally inspected

establishment. The first outbreak occurred during July through October 2015, resulting in a recall of whole hogs for barbeque and targeted

FSIS sampling at the establishment. FSIS isolated Salmonella from carcass and pre-operational food contact swabs and cecal contents, with

isolates characterized as the outbreak strain as defined by serotyping and pulsed-field gel electrophoresis (PFGE) analysis. As a result,

additional whole hogs and fabricated pork products were recalled and FSIS issued a Notice of Intended Enforcement (NOIE) to the

establishment. An NOIE informs an establishment that there is a basis for FSIS to withhold the marks of inspection or to suspend inspection

and it can present corrective actions and planned preventive measures to achieve compliance to FSIS within three business days. The

establishment voluntarily closed its operation in August 2015 in response to the outbreak investigation. The establishment resumed operations

in June 2016 after FSIS held the NOIE in deferral in response to the establishment’s proffered corrective actions and preventive measures to

reduce the risk of contamination and achieve compliance. Shortly after the establishment reopened in June 2016, a second outbreak

investigation linked illnesses among attendees at early July 2016 pig roast events to this establishment. In response to the second outbreak,

pork products were recalled, Establishment A voluntarily suspended operations, and FSIS rescinded its grant of inspection in response to the

establishment’s request. As a result of these outbreak investigations, FSIS is collaborating with public health partners, researchers, and

industry to enhance its understanding of this important pathogen. Additionally, FSIS and the Animal and Plant Health Inspection Service

(APHIS) are continuing discussions to improve processes and procedures specific to pre-harvest investigations.

2015 Outbreak

The 2015 outbreak included 192 case-patients from 5 states (AK, CA, ID, OR, WA) with 96% (184/192) of case-patients from the state of

Washington. Case-patient onset dates ranged from April 25, 2015 through October 6, 2015 (Figure 1); 49% (95/192) were male; the median

age was 35 years (range: <1–90 years); and 17% (30/180) were hospitalized. Case-patients were infected with Salmonella I 4,[5],12:i:- with one

of the following PFGE patterns: JPXX01.1314, JPXX01.2429, JPXX01.3161, JPXX01.2311, and JPXX01.3336; or Salmonella Infantis with PFGE

pattern JFXX01.0046. Whole genome sequencing (WGS) was conducted and showed that isolates of all 5 Salmonella I 4,[5],12:i:- PFGE

patterns were highly related to one another, and that all of the Salmonella Infantis isolates were highly related to one another. Antimicrobial

susceptibility testing was conducted on 21 clinical isolates; 95% (20/21) were resistant to ampicillin, streptomycin, sulfisoxazole, and

tetracycline (ASSuT resistance profile); 5% (1/20) had the ASSu resistance profile. 76% (94/123) of case-patients reported eating pork in the

week before becoming ill; case-patients were exposed to pork at one of several different events, including sub-clusters associated with

restaurants/caterers and at hog roasts (Table 1). CDC responded to a WADOH request for federal government assistance by joining state and

local public health officials in Washington for the investigation as part of an Epi-Aid; an FSIS staff was invited to be part of the Epi-Aid.

Traceback

Traceback by FSIS confirmed that 59% (55/94) of case-patients who consumed pork reported consuming pork produced by

Establishment A.

Many of these case-patients consumed pork from whole hogs that were purchased raw from Establishment A and cooked at hog

roasts.

Additional case-patients may have consumed pork from Establishment A, but this was not verified due to a lack of product

purchase information.

Multiple case-patients did not report consuming pork, but purchased other foods at locations that received pork products from

Establishment A.

Seattle & King County Public Health inspected these locations and identified cross-contamination and other food handling

violations, indicating that cross-contamination from pork to other products may have been the source of illness in these casepatients.

Sampling
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FSIS collected 16 environmental, 14 carcass swab, and 8 cecal samples from Establishment A.

100% (14/14) of carcass swabs were Salmonella positive and 43% (6/14) were identified as the outbreak strain of Salmonella I 4,

[5],12:i:- or Infantis.

100% (8/8) of the cecal samples were Salmonella positive and all of them were identified as the outbreak strain of Salmonella I 4,

[5],12:i:-.

50% (8/16) of the environmental samples (including pre-operational food contact surface) were Salmonella positive, and 75%

(6/8) were identified as the outbreak strain of Salmonella I 4,[5],12:i:- or Infantis.

93% (14/15) of the Salmonella I 4,[5], 12:i:- outbreak strains exhibited the ASSuT resistance profile.

Regulatory Actions

Following a Public Health Alert, the establishment initially recalled specific lots of whole hogs produced on various dates between April

18, 2015 and July 27, 2015 and later issued an expansion that included additional whole hogs and fabricated pork products produced on

various dates between April 18, 2015 and August 26, 2015.

FSIS issued an NOIE to Establishment A on August 11, 2015. The establishment remained under the NOIE until withdrawal from the grant

of inspection.

Establishment Actions

Establishment A voluntarily suspended operations on August 26, 2015 until June 13, 2016.

The establishment hired a consultant and worked with FSIS field inspectors to assess procedures, ensure compliance with FSIS

guidelines, and improve its slaughter processes. Actions taken by the establishment included:

Ensuring understanding of typical pre-evisceration and post-chill levels of Salmonella, based on the FSIS Market Hogs Survey.

Applying recommended sanitation best practices to scalding and singeing steps.

Antimicrobial intervention and verification sampling procedures to address Salmonella.

Chilling carcasses to a specific temperature within a defined time period and maintaining refrigeration throughout commerce

Establishment A began producing roaster hogs again in June 2016.

2016 Outbreak

The 2016 outbreak included 15 case-patients from Washington. Case-patient onset dates ranged from June 1, 2016 to August 10, 2016; 67%

(10/15) were male; the median age was 26 years (range: 8-72); and none were hospitalized. Case-patients were infected with Salmonella I 4,

[5],12:i:- with PFGE pattern JPXX01.1314. Antimicrobial susceptibility testing was conducted on 3 clinical isolates and all had the ASSuT
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resistance profile. Among the case-patients with available information, 93% (13/14) reported pork exposure, with most case-patients (90%,

9/10) reported eating pork at hog roasts held on July 2, 2016 or July 3, 2016.

Traceback

Traceback conducted by WADOH and FSIS identified Establishment A as the supplier for two hog roasts where case-patients were

exposed to contaminated product.

Sampling

(Note: All samples were collected 7-10 days after the establishment had ceased operations)

FSIS collected 40 environmental and 20 carcass swab samples from Establishment A.

20% (4/20) of the carcass samples were Salmonella positive and 75% (3/4) were identified as the outbreak strain of Salmonella I

4,[5], 12:i:-, which exhibited the ASSuT resistance profile.

3% (1/40) environmental sample was found to be positive, and it was also identified as an outbreak strain of Salmonella I 4,

[5],12:i:-, which exhibited the ASSuT resistance profile (Note: Environmental samples were held longer than typical for that type of

sample prior to analysis, which may have affected recovery of Salmonella).

WGS analyses performed by FSIS demonstrated that isolates from Establishment A were highly related to Washington casepatients from both 2015 and 2016 outbreaks.

Regulatory Actions

Following a Public Health Alert, the establishment recalled approximately 11,658 pounds of pork products.

Establishment Actions

Establishment A voluntarily suspended operations and consulted with FSIS regarding additional improvements to their processes and

decreasing contamination of their product.

The last day the establishment operated was on August 11, 2016.

Table 1: Summary of 2015 and 2016 Outbreak Investigations

2015 2016

States AK, CA, ID, OR, WA WA

Case Counts 192 15

Illness Onset Dates 4/25/15 to 10/6/15 6/1/16 to 8/10/16

Hospitalization 17% 0%

Gender 49% male 67% male

Age Range (Median) <1–90 (35) 8-72 (26)

PFGE Pattern(s) JPXX01.1314, JPXX01.2429, JPXX01.3161,

JPXX01.2311, JPXX01.3336; JFXX01.0046

(Salmonella Infantis)

JPXX01.1314

Antimicrobial Susceptibility ASSuT ASSuT

Pork Exposure 76% 93%

Lessons Learned
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CDC and Washington included FSIS in an Epi-Aid which promoted collaboration and data sharing, which alleviated some of the

communication challenges encountered early on during the 2015 investigation; CDC plans to consider inviting FSIS participation for

future Epi-Aids.

Early notification of outbreak from Washington in addition to availability of specific purchase and product information enabled FSIS to

conduct timely traceback that shortened the time from outbreak notification to recall action in 2016.

Timely and frequent communications among FSIS program areas and with federal and state partners are essential for decision-making

with clear understanding of roles and responsibilities to facilitate root cause analysis and eliminate the source of contamination.

Policy-Related and Follow-up

In December 2016 , FSIS published guidelines on safe transport, preparation, cooking, and packing leftovers regarding pig roasts.

During 2015, and prior to the outbreak investigation, FSIS began national exploratory sampling, which is intended to estimate the

national prevalence of Salmonella in pork products that may be used to establish performance standards and provide industry

guidance: Includes sampling of intact and non-intact whole muscle and comminuted pork products;

Results were used to inform the development of a baseline study for these products to:

Determine prevalence of Salmonella and other bacterial organisms in pork products

Inform policy decisions which could include establishing a performance standard or other guidance for industry

Phase 1 of this exploratory sampling project was completed in November 2015; phase II began on June 1, 2017. The agency has

been conducting interim analyses for Salmonella between Phase 1 and the start of the baseline study (January 2016 through

April 2017).

In FY2016, 12% (97/694) intact cuts of pork products tested positive for Salmonella; samples were collected from 188

establishments.

In 2014, a Memorandum of Understanding (MOU) was signed between FSIS and APHIS to assess the root cause of foodborne outbreaks

related to FSIS-regulated products.

FSIS and APHIS are continuing discussions to improve processes and procedures specific to pre-harvests investigations.

Since January 2017, APHIS has been participating in FSIS’ weekly meeting that discusses ongoing foodborne illness investigations.

Available Guidance for Industry

Compliance Guideline for Controlling Salmonella in Market Hogs

Notice 30-17, Raw Pork Products Sampling Program Phase II

The Nationwide Microbiological Baseline Data Collection Program: Market Hogs Survey August 2010 – August 2011

Additional Information for Consumers

Public Health Alert, July 31, 2015

Public Health Alert, July 20, 2016

Recall and Expansion

Recall 110-2015, August 13, 2015

Recall 110-2015 expansion, August 27, 2015

Recall 062-2016, July 21, 2016

CDC final web posting for Multistate Outbreak of Multidrug-Resistant Salmonella I 4,[5],12:i:- and Salmonella Infantis Infections Linked to

Pork, December 2, 2015

Pig Roasting and Food Safety, December 21, 2016

Last Modified May 20, 2020