{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,23]],"date-time":"2026-04-23T10:51:12Z","timestamp":1776941472187,"version":"3.51.4"},"reference-count":52,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2024,12,11]],"date-time":"2024-12-11T00:00:00Z","timestamp":1733875200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"French interministerial program for research and development in the fight against CBRN (Chemical, Biological, Radiological, and Nuclear) threats."}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Toxins"],"abstract":"<jats:p>Food poisoning outbreaks frequently involve staphylococcal enterotoxins (SEs). SEs include 33 distinct types and multiple sequence variants per SE type. Various mass spectrometry methods have been reported for the detection of SEs using a conventional bottom-up approach. However, the bottom-up approach cannot differentiate between all sequence variants due to partial sequence coverage, and it requires a long trypsin digestion time. While the alternative top-down approach can theoretically identify any sequence modifications, it generally provides lower sensitivity. In this study, we optimized top-down mass spectrometry conditions and incorporated a fully 15N-labeled SEA spiked early in the protocol to achieve sensitivity and repeatability comparable to bottom-up approaches. After robust immunoaffinity purification of the SEA, mass spectrometry signals were acquired on a Q-Orbitrap instrument operated in full-scan mode and targeted acquisition by parallel reaction monitoring (PRM), enabling the identification of sequence variants and precise quantification of SEA. The protocol was evaluated in liquid and solid dairy products and demonstrated detection limits of 0.5 ng\/mL or ng\/g in PRM and 1 ng\/mL or ng\/g in full-scan mode for milk and Roquefort cheese. The top-down method was successfully applied to various dairy products, allowing discrimination of contaminated versus non-contaminated food, quantification of SEA level and identification of the variant involved.<\/jats:p>","DOI":"10.3390\/toxins16120535","type":"journal-article","created":{"date-parts":[[2024,12,11]],"date-time":"2024-12-11T06:44:05Z","timestamp":1733899445000},"page":"535","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Quantification of Staphylococcal Enterotoxin A Variants at Low Level in Dairy Products by High-Resolution Top-Down Mass Spectrometry"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-6538-0264","authenticated-orcid":false,"given":"Nina","family":"Aveilla","sequence":"first","affiliation":[{"name":"CEA, INRAE, D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9 (DMTS), SPI, Universit\u00e9 Paris-Saclay, 91191 Gif-sur-Yvette, France"},{"name":"Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Universit\u00e9 Paris-Est, 94700 Maisons-Alfort, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9098-1767","authenticated-orcid":false,"given":"C\u00e9cile","family":"Feraudet-Tarisse","sequence":"additional","affiliation":[{"name":"CEA, INRAE, D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9 (DMTS), SPI, Universit\u00e9 Paris-Saclay, 91191 Gif-sur-Yvette, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dominique","family":"Marc\u00e9","sequence":"additional","affiliation":[{"name":"CEA, INRAE, D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9 (DMTS), SPI, Universit\u00e9 Paris-Saclay, 91191 Gif-sur-Yvette, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8216-6367","authenticated-orcid":false,"given":"Abdelhak","family":"Fatihi","sequence":"additional","affiliation":[{"name":"Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Universit\u00e9 Paris-Est, 94700 Maisons-Alfort, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6787-4149","authenticated-orcid":false,"given":"Fran\u00e7ois","family":"Fenaille","sequence":"additional","affiliation":[{"name":"CEA, INRAE, D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9 (DMTS), SPI, Universit\u00e9 Paris-Saclay, 91191 Gif-sur-Yvette, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jacques-Antoine","family":"Hennekinne","sequence":"additional","affiliation":[{"name":"Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Universit\u00e9 Paris-Est, 94700 Maisons-Alfort, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6071-8255","authenticated-orcid":false,"given":"St\u00e9phanie","family":"Simon","sequence":"additional","affiliation":[{"name":"CEA, INRAE, D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9 (DMTS), SPI, Universit\u00e9 Paris-Saclay, 91191 Gif-sur-Yvette, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7550-425X","authenticated-orcid":false,"given":"Yacine","family":"Nia","sequence":"additional","affiliation":[{"name":"Laboratory for Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Universit\u00e9 Paris-Est, 94700 Maisons-Alfort, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1075-9980","authenticated-orcid":false,"given":"Fran\u00e7ois","family":"Becher","sequence":"additional","affiliation":[{"name":"CEA, INRAE, D\u00e9partement M\u00e9dicaments et Technologies pour la Sant\u00e9 (DMTS), SPI, Universit\u00e9 Paris-Saclay, 91191 Gif-sur-Yvette, France"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,12,11]]},"reference":[{"key":"ref_1","unstructured":"(2024, July 25). 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