Refined liquid smoke flavouring and Listeria bacteria on cold-smoked salmon
What it found
Coating cold-smoked salmon with refined liquid smoke flavouring cut Listeria-like bacteria by about 100-fold over two weeks in lab tests.
A taste test of 180 people found the coating did not noticeably change the fish's overall quality.
What they found
Studies in people
Taste and appearance unchanged
In a simple difference test, 180 untrained tasters could not reliably tell apart salmon treated with the AM-3 liquid smoke from untreated salmon. More than 80% of tasters thought samples were different even when given identical pieces, showing natural variation between fish strips mattered more than the treatment.
Animal and lab studies
Bacteria reduced in lab tests
In lab dishes, three of the four liquid smoke products strongly stopped the growth of Listeria-like bacteria. One product, called 1291, did not work well.
Bacteria on smoked salmon
When applied to cold-smoked salmon, two refined liquid smoke products cut bacteria counts by about 100-fold after 14 days at 4°C. The bacteria were not completely wiped out, but they did not grow back during 35 days of storage.
Other findings
Colour changes measured
Salmon coated with liquid smoke showed measurable colour differences compared to untreated fish. Because the values were above 3.0 on the scale used, the authors say a person would likely notice the colour shift.
What the authors conclude
- They conclude that refined liquid smoke derivatives effectively held back the growth of Listeria-like bacteria on vacuum-packed cold-smoked salmon for 35 days at 4°C.
- They recommend using the AM-3 or AM-10 products as antimicrobial additives to give the fish an extra margin of safety without causing unwanted taste changes.
How it was done
Cold-smoked salmon is eaten without cooking, so any Listeria bacteria present can survive and cause illness. The authors wanted to see if refined liquid smoke could control these bacteria without adding a strong smoky taste or dark colour.
They tested four liquid smoke products against Listeria bacteria in lab dishes. They then coated strips of cold-smoked salmon with two of those products at about 1% by weight, added bacteria, vacuum-sealed the fish, and stored it at 4°C for up to 35 days. Finally, 180 untrained tasters checked whether one product changed how the salmon tasted or looked.
What it can’t tell you
- These tests used a stand-in bacteria in lab dishes and on fish, so they cannot show exactly what happens with real Listeria in people who eat the salmon.
- The taste test only checked whether people noticed a difference, not whether they liked the treated fish more or less.
Who paid
- Authors work at
- University of Alaska Fairbanks, USA
The paper
- Title
- Refined liquid smoke: a potential antilisterial additive to cold-smoked sockeye salmon (Oncorhynchus nerka)
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Montazeri N, Himelbloom BH, Oliveira AC, Leigh MB, Crapo CA (2013). Refined liquid smoke: a potential antilisterial additive to cold-smoked sockeye salmon (Oncorhynchus nerka). Journal of food protection. doi:10.4315/0362-028X.JFP-12-368Free full textPubMed 23643122DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error