{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,22]],"date-time":"2026-02-22T19:45:55Z","timestamp":1771789555738,"version":"3.50.1"},"reference-count":43,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2024,12,28]],"date-time":"2024-12-28T00:00:00Z","timestamp":1735344000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FCT","award":["2021.06413.BD"],"award-info":[{"award-number":["2021.06413.BD"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Plant-derived essential oils (EOs) possess significant antimicrobial potential against spoilage and pathogenic microorganisms. However, their efficacy can vary depending on the test method, making it difficult to standardise results. This study aimed to investigate the effect of polysorbate 80, a common surfactant used to emulsify EOs, on antimicrobial activity and minimum inhibitory concentration (MIC) determinations. The antimicrobial activity of oregano and thyme EOs was tested against 40 microorganisms with and without the presence of polysorbate 80. Antimicrobial activity was qualitatively assessed using the disc diffusion assay (DDA) and quantitatively via broth microdilution to determine MIC values. Both oregano and thyme EOs exhibited antimicrobial activity against all tested microorganisms in the DDA, regardless of the surfactant\u2019s presence. However, MIC determinations revealed that higher EO concentrations were required to inhibit microbial growth when polysorbate 80 was included in the emulsification process. These findings indicate that polysorbate 80 influences antimicrobial test results by reducing EO efficacy while enhancing solution homogeneity and handling in aqueous media. The study highlights the critical role of emulsifiers in antimicrobial testing, as their use can significantly impact the interpretation of results and the perceived effectiveness of EOs in food preservation, pharmaceuticals, and other applications.<\/jats:p>","DOI":"10.3390\/molecules30010081","type":"journal-article","created":{"date-parts":[[2025,1,1]],"date-time":"2025-01-01T14:35:42Z","timestamp":1735742142000},"page":"81","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Impact of Polysorbate 80 on the Antimicrobial Activity of Oregano and Thyme"],"prefix":"10.3390","volume":"30","author":[{"given":"Marta","family":"Carvalho","sequence":"first","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF-Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua de Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5879-9458","authenticated-orcid":false,"given":"Joana","family":"Barbosa","sequence":"additional","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF-Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua de Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8371-2139","authenticated-orcid":false,"given":"Marcelo Belchior Rosendo","family":"da Silva","sequence":"additional","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF-Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua de Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2798-1924","authenticated-orcid":false,"given":"Helena","family":"Albano","sequence":"additional","affiliation":[{"name":"Escola Superior de Enfermagem de Coimbra, 3004-011 Coimbra, Portugal"},{"name":"CISAS\u2014Center for Research and Development in Agrifood Systems and Sustainability, Instituto Polit\u00e9cnico de Viana do Castelo, Rua Escola Industrial e Comercial de Nun\u2019\u00c1lvares, 4900-347 Viana do Castelo, Portugal"},{"name":"Escola Superior Agr\u00e1ria, Instituto Polit\u00e9cnico de Viana do Castelo, R. D. Mendo Afonso 147, Ref\u00f3ios, 4990-706 Ponte de Lima, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6296-5137","authenticated-orcid":false,"given":"Paula","family":"Teixeira","sequence":"additional","affiliation":[{"name":"Universidade Cat\u00f3lica Portuguesa, CBQF-Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Rua de Diogo Botelho 1327, 4169-005 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,12,28]]},"reference":[{"key":"ref_1","first-page":"23289","article-title":"Antimicrobial activity of essential oils of cultivated oregano (Origanum vulgare), sage (Salvia officinalis), and thyme (Thymus vulgaris) against clinical isolates of Escherichia coli, Klebsiella oxytoca, and Klebsiella pneumoniae","volume":"26","author":"Fournomiti","year":"2015","journal-title":"Microb. Ecol. 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