Posted:
2025-01-27
The Practice-based Evidence in Nutrition: PEN® team was recently asked to consider adding information about liquid smoke into the PEN System as dietitians have been asked questions about it by their clients. An example of a question was, “Are food products with liquid smoke flavour (e.g. smoked almonds, smoked tofu) associated with health risks?”
Liquid smoke (also called smoke flavouring) has historically been considered a safer alternative to conventionally smoking foods (1,2). It is produced from smoke passed through a tube from a combustion chamber filled with select wood chips (e.g. mesquite, hickory, applewood, and pecan) to a condenser where the smoke cools and forms a liquid helped by the addition of water (3). Liquid smoke can be used for flavouring and in food preservation (3).
In 2024, member countries of the European Union (EU) endorsed a recommendation by the European Food Safety Authority (EFSA) to deny the renewal of the safety authorization for liquid smoke formulations available in the EU and to begin phasing them out of production in EU member countries (1,2). This decision was based on the presence of genotoxic substances in six formulations of smoke flavourings and a lack of data ruling out the presence of genotoxic substances in two formulations (4). Although the EFSA did not directly investigate the effect of consuming certain quantities of foods flavoured with liquid smoke on human health, they applied a cautionary principle to avoid any possible risk (4).
The UK has approved the same eight smoke flavourings that were previously available in the EU, although these approvals will need to be renewed in summer 2025 (5,6). Canada and the US allow liquid smoke flavourings below a certain threshold and have not recently changed their regulations or safety assessments (2).
Liquid smoke is a complex mixture of components. According to new rules set by the EFSA in 2021, a complex mixture is considered genotoxic if any one of its components is genotoxic, regardless of the amount or proportion (4).
Liquid smoke has historically been considered safer than conventional smoking processes because of the distillation process used to create it (7). Most of the compounds in smoke that have long been known to be toxic, such as Polycyclic Aromatic Hydrocarbons (PAH), settle out of solution and are largely filtered out during the distillation process (7). Although the toxic compounds are not entirely removed, the amount of these compounds left in the smoke flavouring after distillation has historically been considered low enough so as not to negatively affect health risk if consumed below a certain level (7). The amount of PAH allowed in conventionally smoked foods is higher than the amount of PAH that would be found in liquid smoke flavourings (7,8).
Additional genotoxic compounds identified in the EFSA’s most recent scientific opinion publications included furan‐2(5H)‐one, styrene, benzofuran and benzene‐1,2‐diol (9-16). Some unidentified compounds also raised concerns for genotoxicity (9-16). In each case, the authors estimated dietary exposure for each smoke flavouring (using DietEx software) and subsequently estimated dietary exposure for each genotoxic compound. They determined that the estimated dietary exposure to DNA‐reactive mutagens and/or carcinogens from liquid smoke flavourings would either be above the EFSA’s established threshold of toxicological concern (0.0025 μg/kg bw per day) or it could not be adequately proven that it wouldn’t be (9-16). Data came primarily from in vitro and murine studies (9-16), which is common for toxicology studies (17).
At this time, Canada, the US and the UK have not followed the EU’s ban. When clients ask about liquid smoke flavourings, dietitians can recommend that consuming items containing liquid smoke is probably fine in moderation.
In addition, dietitians can educate their clients about the difference between smoked foods and smoke flavourings. Smoked foods are not an acceptable substitute for smoke flavourings, as they contain toxic compounds in higher amounts than smoke flavourings. Smoked foods are still available in EU countries, providing that they do not exceed maximum acceptable levels of contaminants (8). Ultimately, however, it is unlikely that EU consumers will have to choose between eating conventionally smoked foods or forgoing smoke flavours entirely. Flavour companies are already beginning to reformulate their smoke flavourings to taste smoky without containing smoke condensates (18,19).
European Commission. Member states endorse withdrawal of smoke flavourings from EU market. April 24, 2024. Newsroom. Available from: https://ec.europa.eu/newsroom/sante/items/827828/en
Schwarcz J. Concerns about smoked foods heat up. McGill Office for Science and Society: Separating Sense from Nonsense. July 12, 2024. Available from: https://www.mcgill.ca/oss/article/health-and-nutrition/concerns-about-smoked-foods-heat
Government of Canada. Food Quality Specifications - Food purchased by Federal Government Departments - Miscellaneous grocery. 2018 Apr. Available from: https://publications.gc.ca/collections/collection_2019/mdn-dnd/D2-531-20-2018-eng.pdf
European Food Safety Authority. Smoke flavourings: Q&A with Wim Mennes, EFSA’s working group chair on flavourings. Newsroom. November 16, 2023. Available from: https://www.efsa.europa.eu/en/news/smoke-flavourings-qa-wim-mennes-efsas-working-group-chair-flavourings
Food Standards Agency. Smoke flavourings authorisation guidance. December 29, 2020; Updated November 20, 2024. Available from: https://www.food.gov.uk/business-guidance/regulated-products/smoke-flavourings-guidance
Food Standards Agency, Food Standards Scotland. Smoke flavouring authorisations. Regulated Food and Feed Products for Great Britain. December 29, 2020; Updated November 20, 2024. Available from: https://data.food.gov.uk/regulated-products/smoke_authorisations
Mcdonald S. Comparison of health risks of smoked foods as compared to smoke flavorings: are smoke flavors “healthier”? Adv Food Tech Nutr Sci. 2015 Dec 16;1(6):130-134. doi: 10.17140/AFTNSOJ-1-122. Available from: https://www.researchgate.net/publication/289555803_Comparison_of_Health_Risks_of_Smoked_Foods_as_Compared_to_Smoke_Flavorings_Are_Smoke_Flavors_Healthier
European Union. Commission Regulation (EU) 2023/915 of 25 April 2023 on maximum levels for certain contaminants in food and repealing Regulation (EC) No 1881/2006 (Text with EEA relevance). EUR-Lex: Access to European Union Law. April 25, 2023; Updated January 1, 2025. Available from: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32023R0915&qid=1736530510704
EFSA Panel name on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Degen G, Engel KH, et al. Scientific opinion on the renewal of the authorisation of Fumokomp (SF-009) as a smoke flavouring Primary Product. EFSA J. 2023 Nov 16;21(11):e08370. doi: 10.2903/j.efsa.2023.8370. PMID: 38027436; PMCID: PMC10652694. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38027436/
EFSA Panel name on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Degen G, Engel KH, et al. Scientific opinion on the renewal of the authorisation of proFagus Smoke R709 (SF-008) as a smoke flavouring Primary Product. EFSA J. 2023 Nov 16;21(11):e08369. doi: 10.2903/j.efsa.2023.8369. PMID: 38027454; PMCID: PMC10652699. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38027454/
EFSA Panel name on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Degen G, Engel KH, et al. Scientific opinion on the renewal of the authorisation of proFagus Smoke R714 (SF-001) as a smoke flavouring Primary Product. EFSA J. 2023 Nov 16;21(11):e08363. doi: 10.2903/j.efsa.2023.8363. PMID: 38027451; PMCID: PMC10652307. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38027451/
EFSA Panel name on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Degen G, Engel KH, et al. Scientific opinion on the renewal of the authorisation of Scansmoke SEF7525 (SF-004) as a smoke flavouring Primary Product. EFSA J. 2023 Nov 16;21(11):e08366. doi: 10.2903/j.efsa.2023.8366. PMID: 38027432; PMCID: PMC10652693. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38027432/
EFSA Panel name on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Degen G, Engel KH, et al. Scientific opinion on the renewal of the authorisation of Smoke Concentrate 809045 (SF-003) as a smoke flavouring Primary Product. EFSA J. 2023 Nov 16;21(11):e08365. doi: 10.2903/j.efsa.2023.8365. PMID: 38027427; PMCID: PMC10652702. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38027427/
EFSA Panel name on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Degen G, Engel KH, et al. Scientific opinion on the renewal of the authorisation of SmokEz C-10 (SF-005) as a smoke flavouring Primary Product. EFSA J. 2023 Nov 16;21(11):e08367. doi: 10.2903/j.efsa.2023.8367. PMID: 38027441; PMCID: PMC10652705. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38027441/
EFSA Panel name on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Degen G, Engel KH, et al. Scientific opinion on the renewal of the authorisation of SmokEz Enviro-23 (SF-006) as a smoke flavouring Primary Product. EFSA J. 2023 Nov 16;21(11):e08368. doi: 10.2903/j.efsa.2023.8368. PMID: 38027452; PMCID: PMC10652696. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38027452/
EFSA Panel name on Food Additives and Flavourings (FAF); Younes M, Aquilina G, Castle L, Degen G, Engel KH, et al. Scientific opinion on the renewal of the authorisation of Zesti Smoke Code 10 (SF-002) as a smoke flavouring Primary Product. EFSA J. 2023 Nov 16;21(11):e08364. doi: 10.2903/j.efsa.2023.8364. PMID: 38027431; PMCID: PMC10652701. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/38027431/
FDA. Toxicology research. January 26, 2024. Available from: https://www.fda.gov/food/science-research-food/toxicology-research
Grylls B. Flavour companies find loophole in EU smoky flavour ban. Food Manufacture. June 14, 2024. Available from: https://www.foodmanufacture.co.uk/Article/2024/06/14/flavour-companies-introduce-smoke-free-smoke-ranges/#:~:text=The%20EU%20ban%20will%20see,is%20shorter%2C%20at%202%20years
Sensient Flavors & Extracts launches SmokeLess Smoke™, a natural, clean-label solution. Sensient. March 19, 2024. Available from: https://sensientflavorsandextracts.com/insights/sensient-flavors-extracts-launches-smokeless-smoke-a-natural-clean-label-solution/