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How did events actually unfold?

The chain of events that led to the initial identification of the outbreak and the eventual recall of contaminated meats produced by Maple Leaf Foods is not easily or succinctly explained.

A foodborne emergency is complex because of the multiple sectors involved and the way Canada's health and food safety systems work.

Three levels of government have different roles to play in such incidents. Within the federal government alone, there are three different organizations, each with unique mandates and functions.

In addition, both the health and food safety systems are science based and depend on sophisticated methodologies and technologies.

Taken together, the reasons why it took several weeks to confirm the source of the outbreak and to stop the distribution of contaminated food became clearer.

In hindsight, we recognize that the first person who developed listeriosis as part of this outbreak became ill in the first week of June. Therefore, contaminated Maple Leaf Foods products were on the market and being consumed before that time.

The problem was not picked up by the surveillance systems designed to identify foodborne outbreaks until later, due in part to the long incubation period. This chapter highlights the key milestones in the 2008 listeriosis outbreak, explaining the decisions and actions of government. A detailed chronology listing all of the events can be found in Appendix B.

What happened and how it happened
What happened	How it happened
July 2008
First 2 listeriosis cases (later identified as part of the outbreak through DNA fingerprinting)	We now know that the pivotal factors concerning this event began to unfold around Thursday July 10th, when the Public Health Agency of Canada's National Microbiology Lab¹- the national reference laboratory for human biological testing - received two Listeria specimens for DNA fingerprinting of the pathogen. These samples were taken from the first two Ontario patients diagnosed with listeriosis by their treating physicians; both would later be associated with the outbreak. We know these patients were from Ontario but the specimens did not have detailed information that would identify them when they reached the reference lab.
Two cases of listeriosis diagnosed in 2 residents of the same Toronto area long-term care home	A few days later, two residents of a Toronto area long-term care home became seriously ill. Based on lab results, the attending physicians diagnosed listeriosis. The original blood tests in these two cases were done by a private laboratory which didn't retain or forward the samples for further testing. This made it impossible later in the investigation to confirm the strain of Listeria that affected these two individuals. Nonetheless, their treating physician reported to Toronto Public Health, his concern that there were two cases of listeriosis involving residents living in the same home.
Wednesday, July 16th
Toronto Public Health inspectors began investigating two cases of listeriosis in the Toronto area long-term care home	With this information, Toronto Public Health investigated the Toronto area long-term care home where the two residents lived, to try to find the cause of their illness. Public health inspectors conducted their investigation considering a potential food handling problem in the kitchen, but also collected food samples to determine if a specific food could have caused the illness.
Friday, July 18th
Match confirmed on DNA fingerprinting from first two human samples	PHAC's National Microbiology Lab confirmed that the two human listeriosis samples received from Ontario on July 10th had matching DNA fingerprints, which meant the two cases were linked.
Monday, July 21st
Toronto Public Health inspectors picked up food samples from a Toronto area long-term care home.	Toronto Public Health went back to the Toronto area long-term care home to collect 11 food products (e.g. sandwiches and cheeses) from samples of meals previously prepared and served at the home (Institutions such as long- term care homes are not required to keep such samples under provincial regulations). When the samples were collected, the name of the food supplier and product identification information such as 'best before' dates were not available or recorded.
Tuesday, July 22nd
No cases appear on Ontario's surveillance system	The Ontario Ministry checked its surveillance system to see if an unusual number of listeriosis cases had been reported from long-term care homes. As not all of the data had been loaded into the surveillance system, the answer came back 'no'.
11 food samples received by Ontario Ministry	The Ontario Ministry received 11 food samples from Toronto Public Health from the investigation launched July 16th.
Wednesday, July 23rd
11 food samples now sent to Reference Laboratory in Ottawa as routine samples	The Ontario Ministry sent the 11 food samples to Health Canada's National Reference Lab in Ottawa, the national reference laboratory for food testing. These food samples were identified as 'routine' with the main symptom noted as 'fever' rather than indicating a death linked to a food safety investigation.
Long-term care home operator withdraws high risk food products	Toronto area long-term care operator stopped serving, at all of its facilities, all foods that could potentially pose a Listeria health risk to its residents, including cold cuts, cheeses and ice cream.
Friday, July 25th
Increased cases now detected on the provincial surveillance system	The Ontario Ministry began to detect an increase in the number of cases of listeriosis, which were now reported on the provincial surveillance system.
Federal monitoring of the event begins
Tuesday, July 29th
Ontario notifies Public Health Agency of Canada that clusters of cases are emerging in the province	The Ontario Ministry concluded that a cluster of illnesses was emerging, although it had limited information on the precise food product that was the source of the disease.
Alert posted on the federal surveillance system	With this pattern detected, the Ministry notified its federal counterpart, the Public Health Agency of Canada (PHAC), and posted an alert on the national surveillance system. This alert was accessible to all provinces and territories, Health Canada, and the CFIA.
Wednesday, July 30th
Conference call with Ontario and the Public Health Agency of Canada to discuss reporting and routing of lab samples Enhanced surveillance alert issued to all Ontario public health units by Ontario Ministry	Following the national surveillance system alert, a conference call was initiated by the Ontario Ministry that included 15 of Ontario's 36 public health units, PHAC, and Health Canada. It was decided that, for all existing cases or new cases identified, each local health unit would submit human samples to the PHAC's National Microbiology Lab and food samples to Health Canada's National Reference Lab via the Ontario Ministry public health laboratory. These samples would be collected by the Ontario Ministry and forwarded to the federal labs. It was also agreed that the Ministry would issue an Enhanced Surveillance Directive to all Ontario public health units, requesting additional and timely reporting of listeriosis cases through the provincial surveillance system as well as providing the information regarding where the human and food samples were to be sent.
Monday, August 4th
Three of 11 food samples from the Toronto area long-term care home test positive for Listeria monocytogenes	The results of the 11 food samples collected from the Toronto area long-term care home on July 21st and tested by Health Canada's National Reference Lab were emailed to the Ontario Ministry. Three of the 11 food samples were positive for Listeria monocytogenes. Since the samples came from a Toronto institution, the Ontario Ministry informed it of the results.>
Federal involvement in the event begins
Wednesday, August 6th
Toronto area long-term care home suspects Maple Leaf Foods products to be the source of listeriosis Help requested from CFIA	The Toronto area long-term care home management suspected that its two residents had contracted listeriosis from eating sandwiches made with deli meats produced at the Maple Leaf Foods Bartor Road plant. The staff shared this information with the Ontario Ministry of Health and Long-term Care. Toronto Public Health requested the Canadian Food Inspection Agency's assistance.
Thursday, August 7th
CFIA initiates a food safety investigation	The CFIA initiated a food safety investigation on the extent and source of the potential food hazard. It received confirmation from Toronto Public Health that Maple Leaf Foods deli meats used in sandwiches taken from the long-term care home tested positive for Listeria monocytogenes.
Friday, August 8th
CFIA conducts document review but no irregularities are reported	The CFIA conducted a document review at Maple Leaf Foods Bartor Road plant to determine if the facility was following its food safety plan. No anomalies were noted or reported.
CFIA requests deli meats distribution records	Late in the day, the CFIA requested distribution records for deli meats. Maple Leaf Foods' Sales Office, which keeps these records, was closed for the weekend.
Monday, August 11th
Distribution records received from Maple Leaf Foods	The CFIA received product distribution records from Maple Leaf Foods that included product codes and 'best before' dates for products that were used at the Toronto long term care home in July. These Sure Slice brand products were mainly sold to institutions, such as hospitals, long term care homes, prisons, restaurants and hotels.
Search begins for unopened food packages to verify the source	Maple Leaf Foods' three largest distributors were contacted, but they had no remaining products matching the specific codes and dates in their inventory. The CFIA broadened its search of suspected products to include other long-term care homes in an attempt to locate any unopened-packages² of the product in their inventory.
How governments responded
Tuesday, August 12th
DNA fingerprint matches cases from several provinces This was the first indication that a national outbreak might be developing	The PHAC's National Microbiology Lab confirmed that DNA fingerprinting patterns on human cases from Ontario matched cases from other provinces, including Newfoundland & Labrador and Quebec. Concurrently, Quebec was beginning to deal with another listeriosis outbreak (of a different DNA fingerprint), this time traced to cheese, which resulted in 38 illnesses and two deaths (plus 3 babies who died at birth or shortly after).
Halton long-term care homes advised to discontinue serving deli meats to residents	Based on the available information, the Halton Region Health Department issued a precautionary advisory to long-term care homes in its region. It notified them that Maple Leaf Foods deli meat products were potentially contaminated and recommended they suspend serving these products to their residents.
Unopened package of suspected meat located and sent for testing to confirm source	Meanwhile, the CFIA located an unopened package of the suspected Maple Leaf Foods meat for testing. The package came from another long-term care home affiliated with the home where the early listeriosis cases were first observed. These unopened food packages were sent to the CFIA's Toronto lab for testing. The CFIA continued to look for samples in long-term care homes and among other clients.
Two cases appeared in a Burlington hospital but were not initially connected to Maple Leaf Food products (were later linked)	The CFIA was also notified by the Halton Region Health Department of two additional listeriosis cases at a hospital in Burlington. However, there was conflicting information initially about these cases. The CFIA was told that two samples of Maple Leaf Foods deli meats served at the hospital had tested positive for Listeria monocytogenes, but it was first reported that the two patients had not consumed the suspected deli meats. Later, it was confirmed that the two patients did, in fact, eat the contaminated meat while in the hospital. Testing confirmed that their illnesses were linked to the outbreak.
A possible link is found between cases at the Burlington hospital and the long-term care home	As was the case with the Toronto area long-term term home, food samples taken from the Burlington hospital did not include product code information. Since product test results from the two institutions could not be linked initially, a separate food safety investigation was initiated by the CFIA. In the course of this new investigation, the CFIA was informed by one of Maple Leaf Foods' distributors of a possible connection between the two institutions. The distributor had delivered deli meats to the Burlington hospital with the same suspected codes as those being investigated at the Toronto area long-term care home.
Wednesday, August 13th
Maple Leaf Foods advises its distributors to hold certain Sure Slice products	Maple Leaf Foods sent a letter to its distributors informing them that the Canadian Food Inspection Agency was investigating illnesses that could be related to its products. It advised distributors to place on hold any remaining inventory of Sure Slice Roast Beef, Corned Beef and Black Forest Ham.
The CFIA initiates a conference call to exchange information	The CFIA organized a teleconference involving the Public Health Agency of Canada, Health Canada, the Ontario Ministry of Health and Long-Term Care and Ontario public health units to update and exchange information. It was learned that listeriosis cases had now been identified in Simcoe, Peterborough and Etobicoke. It was also discussed that Maple Leaf Foods products could be the possible source of the outbreak.
Ontario public health units conduct a food sampling blitz	Ontario Public health units agreed to support the CFIA by undertaking a large scale sampling 'blitz' to cover all Sure Slice brand products with 'best before' dates from August 1 to September 30, 2008 of products that were likely to be still in the marketplace produced on two suspected production lines at Maple Leaf Foods Bartor Road plant.
Decision made that more information needed prior to recall	The conference call concluded that more precise information regarding human health hazard and exposure was needed before the CFIA, in collaboration with Health Canada, could initiate a food recall. It was believed that the Sure Slice deli meats had only been distributed to large institutions, so it was not necessary to notify the general public. These products were not thought to be sold to retailers.
The Public Health Agency of Canada notifies labs country-wide of cases in multiple provinces	At the same time, the PHAC's National Microbiology Lab notified labs across Canada that DNA fingerprinting showed a clustering of human cases of listeriosis with a similar strain in more than one province.
The CFIA identifies a possible link between Bartor Road plant and positive food samples	By now, the CFIA had identified a possible link among five positive food samples - three from the Toronto area long-term care home and two from the Burlington hospital. The CFIA's review of production and distribution records at Maple Leaf Foods Bartor Road plant indicated the suspected products might all have originated on production lines 8 and 9.
Thursday, August 14th
Confirmation that 1st listeriosis death in mid-June linked to consumption of deli meats	The first death linked to the consumption of contaminated Maple Leaf Foods deli meat products was confirmed as having occurred on June 17, 2008.
Toronto Public Health advises all institutions to stop serving Sure Slice products	Toronto Public Health inspectors started contacting all institutions within their jurisdiction to advise them not to use Maple Leaf Foods Sure Slice brand products (as per Maple Leaf Foods' advisory to its distributors the previous day).
Friday, August 15th
The Public Health Agency of Canada assumes coordinating role in the epidemiological investigation	The PHAC assumed the coordinating role for the epidemiological investigation of the outbreak since cases of listeriosis were now being identified nationally. This was done according to the Foodborne Illness Outbreak Response Protocol (FIORP).
Public Health Agency of Canada issues alert to all public health authorities in Canada	The PHAC issued an alert to all public health authorities across Canada about the Ontario outbreak and requested they collect information on the consumption of deli meats for cases matching the DNA fingerprint associated with the outbreak.
Ontario institutions advised to stop serving Sure Slice products	In turn, the Ontario Ministry instructed all public health units to contact all hospitals, nursing homes, long-term care homes and seniors' residences in the province and recommend they stop using Maple Leaf Foods Sure Slice brand products (as per Maple Leaf Foods' advisory of August 13th ).
Saturday, August 16th
The CFIA confirms Listeria monocytogenes in unopened Sure Slice package	The CFIA confirmed a positive test result for Listeria monocytogenes from an unopened Sure Slice package, collected on August 12th, which had been produced at Maple Leaf Foods Bartor Road plant. The CFIA's assessment determined that Sure Slice Roast Beef and Corned Beef met the criteria for the highest level of risk for health which requires recalling the product to protect the public. The CFIA contacted Maple Leaf Foods to inform the company of this result and to advise it that the Agency was preparing to issue a "Health Hazard Alert" for the two specific product codes of Sure Slice products.
Sunday, August 17th
Public warned not to eat 2 Sure Slice products	At 2 a.m., the CFIA issued a 'Health Hazard Alert' warning the public not to consume or serve Sure Slice Roast Beef and Corned Beef. The Alert also stated that the CFIA had not yet been able to link the DNA fingerprints between the human listeriosis cases and the recalled Maple Leaf Foods products.
1st recall of Maple Leaf Foods brand products	At 3:30 a.m., Maple Leaf Foods announced it was voluntarily recalling two Sure Slice brand products sold in 1 kilogram packages.
Tuesday, August 19th
2nd recall of Maple Leaf Foods brand products	The CFIA issued a second 'Health Hazard Alert' warning the public not to consume or serve 23 additional deli meat products from lines 8 and 9 of Maple Leaf Foods Bartor Road plant. This new 'Health Hazard Alert' was based on the first results from the sampling blitz conducted in Ontario. The CFIA initiated another teleconference with the Public Health Agency of Canada, Health Canada, the Ontario Ministry and Ontario public health units, during which the PHAC continued to coordinate the epidemiological portion of the discussion.
Toronto Public Health alerts physicians and institutions	Toronto Public Health sent a surveillance alert to physicians and institutions about the outbreak.
Wednesday, August 20th
Maple Leaf Foods suspends all production at its Bartor Road plant	Maple Leaf Foods suspended all production at its Bartor Road plant and announced that it was voluntarily recalling the 23 other deli meat products originating from the plant.
Verification to ensure removal of contaminated products	The CFIA also initiated verification checks, with the assistance of various public health teams across the country, to ensure recalled products had been removed from the market with special emphasis on institutions (hospitals, long-term care homes and day cares).
Products from Bartor Road held until Listeria test results are negative	The CFIA ordered Maple Leaf Foods to implement a hold and test protocol. This meant that no meat product produced at Maple Leaf Foods Bartor Road would be made available to consumers before test results for Listeria monocytogenes were found to be negative.
Thursday, August 21st
18 products test positive - already on recall lists	The CFIA Labs confirmed the 18 Sure Slice products tested following the Ontario sampling blitz were positive and already on the recall lists.
Friday, August 22nd
Public Health Agency of Canada activates its Emergency Operations Center	The PHAC partially activated its Emergency Operations Center to "Increased Vigilance' (Level 2)
1st federal press conference	Senior executives from the PHAC, the CFIA, and Health Canada held a joint press conference to inform the public of the food safety investigation.
1st of 21 secondary food recalls	The day also marked the first of a series of secondary recalls - 21 in total. Secondary recalls were required since a variety of foods (e.g. sandwiches, meat and cheese platters, and pizza) were prepared using Maple Leaf Foods deli meats that had been recalled. The new products were sold by different companies under various brand names.
Saturday, August 23rd
LINK CONFIRMED BETWEEN HUMAN ILLNESS AND CONTAMINATED DELI MEATS	The test results from the unopened package confirmed the link between the listeriosis outbreak and contaminated products from Maple Leaf Foods Bartor Road plant
3rd recall of Maple Leaf Foods brand products 2nd Federal press conference confirming the link between listeriosis and Maple Leaf Food products	The Minister of Agriculture and Agri-Foods, assisted by senior executives of the PHAC, the CFIA, and Health Canada, held a press conference to announce that the DNA fingerprints of the strain of Listeria monocytogenes found in humans and in the Maple Leaf Foods products were linked. This would be the first in a series of fifteen consecutive daily federal media briefings by a Minister. A press release was also issued with the same information.
Maple Leaf Foods CEO takes responsibility for the outbreak Voluntary recall of all products from Bartor Road	The Maple Leaf Foods' CEO broadcast a national network television message taking responsibility for the outbreak following the determination that Maple Leaf Foods' Bartor Road plant was the source of the contaminated food that caused listeriosis. Maple Leaf Foods also indicated that, as a precaution, it was voluntarily expanding its product recall to include all 191 items produced at the Bartor Road plant. They took a zero risk approach by recalling all products from the marketplace, as they had no means to assure that the contamination at the plant could not have been more dispersed, including products which best before dates had expired but that could have been stored in freezers. The CFIA requested a health risk assessment from Health Canada on all products from the Bartor Road plant and notified Maple Leaf Foods that the assessment had been initiated.
Sunday, August 24th
'Health Hazard Alert' for all products	The CFIA issued an expanded 'Health Hazard Alert' to cover all products produced at Maple Leaf Foods at Bartor Road. Maple Leaf Foods issued a press release confirming its previous day's TV announcement that "[Maple Leaf Foods] voluntarily expanded its recall of products manufactured at its Bartor Road plant in Toronto, as a precautionary measure."
Federal Minister of Health holds press conference	The federal Minister of Health held a news conference, assisted by senior executives of the PHAC, the CFIA and Health Canada to respond to questions regarding the listeriosis outbreak and food recall.
Monday, August 25th
News conference led by Minister of Agriculture and Agri-food; continued daily for 13 days	The Minister of Agriculture and Agri-food Canada resumed the federal lead on the file, holding a news conference assisted by senior executives of the PHAC, the CFIA and Health Canada to respond to media questions. From this point forward until the federal election call on September 8th, the federal government held a 4 p.m. daily news conference, led by the Minister of Agriculture and Agri-food Canada, assisted by senior executives from the PHAC, the CFIA and Health Canada, as work continued to identify all illness cases linked to the outbreak as well as all the necessary secondary food recalls.
Friday, September 5th
All federally-regulate. ready-to-eat meat plants advised of new rules on slicer sanitation	The CFIA issued an advisory on slicers to all federally registered establishments processing ready-to-eat meats. Companies were directed to ensure that meat slicers were completely dismantled and cleaned, that they collected environmental samples to test for Listeria, and to review cleaning and disinfecting procedures with their CFIA inspector to ensure proper sanitation of the slicers. This change led to further Listeria contamination investigations and some product recalls from various food processors later in the fall.
Maple Leaf Foods announces results of its panel of International Food Safety Experts review Slicing machines most likely source of food contamination	The Maple Leaf Foods' CEO updated the public on the results of the Bartor Road plant investigation by its panel of International Food Safety Experts, indicating that the most likely source of Listeria monocytogenes was contamination in the slicing machines.
Saturday, September 6th
Last federal news conference before election call	The Minister of Agriculture and Agri-food Canada held the last of fifteen news conferences, assisted by senior executives from the PHAC, the CFIA and Health Canada.
Monday, September 8th
The PHAC back to 'Normal Readiness'	The PHAC's Emergency Operations Centre was de-activated to 'Normal Readiness' (Level 1).
Wednesday, September 17th
Bartor Road operations resumed	Maple Leaf Foods received the CFIA's approval to restart its operations at the Maple Leaf Foods Bartor Road plant. The company's operations had been suspended on August 20th. The conditions set by the CFIA to resume production required that all products be tested for Listeria monocytogenes prior to being distributed to market.

Next chapter

"The previous chapter outlined the chain of events that culminated in the 2008 outbreak. As illustrated in our descriptive chronology, investigating a foodborne illness outbreak is highly complex..."

¹ National Microbiology Laboratory in Winnipeg

² Meat from unopened packages was sought to provide conclusive evidence that these products were the source of the listeriosis outbreak, which is standard recall procedure.