According to the notice, "The recall was initiated because the product’s water phase salt (WPS) tested below 3.5%. This was discovered upon re-review of laboratory certificates, which were found to have incorrectly reported WPS levels. Labeling instructions state to keep refrigerated at or below 38ºF and that the product may be frozen. Because the WPS is under 3.5% the product must remain frozen until ready to consume. Product stored in the refrigerator after thawing has the potential to be contaminated with Clostridium botulinum."
As a cold smoked fish product, the hazard of concern is the non-proteolytic strains of Clostridium botulinum, specifically Type E, that have the ability to grow at refrigeration temperatures in vacuum packed product. (Proteolytic strains, those often associated with improperly processed home canned foods require higher temperatures). The salt content is a hurdle that prevents this growth, and if not at the right level, than growth can be an issue.
https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/mill-stream-corp-sullivan-harbor-farm-issues-voluntary-recall-cold-smoked-salmon-because-possible
Mill Stream Corp. (Sullivan Harbor Farm) Issues a Voluntary Recall of Cold Smoked Salmon Because of Possible Health Risk
Summary
Company Announcement Date: November 06, 2019
FDA Publish Date: November 06, 2019
Product Type: Food & Beverages
Reason for Announcement: Clostridium botulinum
Company Name: Mill Stream Corp.
Brand Name: Mill Stream Corp.
Product Description: Cold Smoked Salmon
https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/mill-stream-corp-sullivan-harbor-farm-issues-voluntary-recall-cold-smoked-salmon-because-possible
Mill Stream Corp. (Sullivan Harbor Farm) Issues a Voluntary Recall of Cold Smoked Salmon Because of Possible Health Risk
Summary
Company Announcement Date: November 06, 2019
FDA Publish Date: November 06, 2019
Product Type: Food & Beverages
Reason for Announcement: Clostridium botulinum
Company Name: Mill Stream Corp.
Brand Name: Mill Stream Corp.
Product Description: Cold Smoked Salmon