title: Quantitative Analysis of Staphylococcal Enterotoxins A and B in Food Matrices Using Ultra High-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS).
abstract: A method that uses mass spectrometry (MS) for identification and quantification of protein toxins, staphylococcal enterotoxins A and B (SEA and SEB), in milk and shrimp is described. The analysis was performed using a tryptic peptide, from each of the toxins, as the target analyte together with the corresponding (13)C-labeled synthetic internal standard peptide. The performance of the method was evaluated by analyzing spiked samples in the quantification range 2.5-30 ng/g (R² = 0.92-0.99). The limit of quantification (LOQ) in milk and the limit of detection (LOD) in shrimp was 2.5 ng/g, for both SEA and SEB toxins. The in-house reproducibility (RSD) was 8%-30% and 5%-41% at different concentrations for milk and shrimp, respectively. The method was compared to the ELISA method, used at the EU-RL (France), for milk samples spiked with SEA at low levels, in the quantification range of 2.5 to 5 ng/g. The comparison showed good coherence for the two methods: 2.9 (MS)/1.8 (ELISA) and 3.6 (MS)/3.8 (ELISA) ng/g. The major advantage of the developed method is that it allows direct confirmation of the molecular identity and quantitative analysis of SEA and SEB at low nanogram levels using a label and antibody free approach. Therefore, this method is an important step in the development of alternatives to the immune-assay tests currently used for staphylococcal enterotoxin analysis.
authors.affiliation: Science Department, National Food Agency, Box 622, Uppsala SE-751 26, Sweden. aida.zuberovic.muratovic@slv.se.
authors.forename: Aida Zuberovic
authors.initials: AZ
authors.lastname: Muratovic
authors.affiliation: Science Department, National Food Agency, Box 622, Uppsala SE-751 26, Sweden. thomas.hagstrom2@gmail.com.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hagström
authors.affiliation: Science Department, National Food Agency, Box 622, Uppsala SE-751 26, Sweden. johan.rosen@slv.se.
authors.forename: Johan
authors.initials: J
authors.lastname: Rosén
authors.affiliation: Science Department, National Food Agency, Box 622, Uppsala SE-751 26, Sweden. kristina.granelli@slv.se.
authors.forename: Kristina
authors.initials: K
authors.lastname: Granelli
authors.affiliation: Science Department, National Food Agency, Box 622, Uppsala SE-751 26, Sweden. karl-erik.hellenas@slv.se.
authors.forename: Karl-Erik
authors.initials: KE
authors.lastname: Hellenäs
mesh_terms: D000818:Animals; D001156:Artemia / Q000382:microbiology; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D004768:Enterotoxins / Q000032:analysis* / Q000633:toxicity; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D057230:Limit of Detection; D016014:Linear Models; D008892:Milk / Q000382:microbiology; D015203:Reproducibility of Results; D017747:Seafood / Q000382:microbiology; D013211:Staphylococcus aureus / Q000254:growth & development / Q000302:isolation & purification; D053719:Tandem Mass Spectrometry
chemical_list: D004768:Enterotoxins; C026066:enterotoxin A, Staphylococcal
keywords: UPLC-ESI-MS/MS; foods; quantification; staphylococcal enterotoxins