Closing the investigation: OICC deactivation
Once all information has been shared among partners, the national Outbreak Investigation Coordinating Committee (OICC) can be deactivated. This can be done by either notifying all investigative partners through a final OICC call, or email.
For this outbreak, it is decided that no final OICC call is needed. Instead, email updates will be sent to all OICC members notifying them that the OICC investigation is closed, the date the outbreak can be declared over, as well as any new information that becomes available (e.g., although two new cases have been reported since the products have been recalled by the CFIA, they both have illness onset dates before the recall). Furthermore, an updated Public Health Notice (PHN) will be posted to inform everyone that the OICC investigation is closed.
Although the OICC is deactivated, the investigation may still continue at a lower level [e.g., enhanced surveillance for new cases meeting the case definition (matching the outbreak cluster code)] for an unspecified time, and new data may still be obtained (e.g., new case interviews, laboratory results).
Following the deactivation of the OICC, results from the CFIA food and environmental samples were received:
Cases’ home samples:
- June 5: One closed and one open chia seed sample from two cases’ homes (in British Columbia and Alberta) were obtained and submitted for testing.
- June 11: Both tested positive for the presence of Salmonella.
- June 18: The samples are determined by WGS to be genetically related to the outbreak strain.
Facility and retail closed product samples:
- June 5: 40 samples were obtained from the facility and at the retail level: eight samples from the recalled lots, 20 samples from the lots packaged on previous and subsequent dates and 12 environmental samples from the facility.
- June 12: Four samples from the recalled lots (unopened product) tested positive for Salmonella. None of the samples from the previous and subsequent lots of chia seeds or from the environmental samples tested positive for Salmonella.
- June 19: All four samples are found to be genetically related by WGS to the outbreak strain.
In addition, the Public Health Agency of Canada (PHAC) re-interviewed BC-18 using the focused questionnaire and determined that the case consumed one of the recalled lots of “Smile” brand chia seeds.
It is important to still include this laboratory and epidemiologic information in final documentation of the outbreak (e.g., final investigation summary, chronology/timeline of events).
As part of the investigation wrap-up, it is important to discuss what caused the contamination, how that happened, and how can we make sure it doesn’t happen again. This information may be obtained during the food safety investigation or by other OICC partners during post-outbreak work and would be shared back with the OICC. In this investigation, the root cause of contamination was not determined, and how the chia seeds became contaminated was not identified.