Application of LC-MS/MS MRM to Determine Staphylococcal Enterotoxins (SEB and SEA) in Milk.
Staphylococcus aureus is one of the important aetiological agents of food intoxications in Europe and can cause gastro-enteritis through the production of various staphylococcal enterotoxins (SEs) in foods. Due to their stability and ease of production and dissemination, some SEs have also been studied as potential agents for bioterrorism. Therefore, specific and accurate analytical tools are required to detect and quantify SEs. Online solid-phase extraction liquid chromatography electrospray ionization tandem mass spectrometry (online SPE-LC-ESI-MS/MS) based on multiple reaction monitoring (MRM) was used to detect and quantify two types of SE (A and B) spiked in milk and buffer solution. SE extraction and concentration was performed according to the European Screening Method developed by the European Reference Laboratory for Coagulase Positive Staphylococci. Trypsin digests were screened for the presence of SEs using selected proteotypic heavy-labeled peptides as internal standards. SEA and SEB were successfully detected in milk samples using LC-MS/MS in MRM mode. The selected SE peptides were proteotypic for each toxin, allowing the discrimination of SEA and SEB in a single run. The detection limit of SEA and SEB was approximately 8 and 4 ng/g, respectively.
Food, Medicine and Consumer Safety, Scientific Institute of Public Health (WIV-ISP), Juliette Wytsmanstraat 14, 1050 Brussels, Belgium. mirjana.andjelkovic@wiv-isp.be.
Mirjana
M
Andjelkovic
Food, Medicine and Consumer Safety, Scientific Institute of Public Health (WIV-ISP), Juliette Wytsmanstraat 14, 1050 Brussels, Belgium. varvara.tsilia@gmail.com.
Varvara
V
Tsilia
Laboratory of Food Microbiology and Food Preservation, Ghent University (UGent), Coupure Links 657, 9000 Ghent, Belgium. andreja.rajkovic@ugent.be.
Andreja
A
Rajkovic
Food, Medicine and Consumer Safety, Scientific Institute of Public Health (WIV-ISP), Juliette Wytsmanstraat 14, 1050 Brussels, Belgium. koen.decremer@wiv-isp.be.
Koen
K
De Cremer
Food, Medicine and Consumer Safety, Scientific Institute of Public Health (WIV-ISP), Juliette Wytsmanstraat 14, 1050 Brussels, Belgium. joris.vanloco@wiv-isp.be.
Joris
J
Van Loco
D000818:Animals; D002853:Chromatography, Liquid; D004768:Enterotoxins / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D008892:Milk / Q000737:chemistry*; D010455:Peptides / Q000032:analysis*; D052616:Solid Phase Extraction; D013211:Staphylococcus aureus; D053719:Tandem Mass Spectrometry
D004768:Enterotoxins; D010455:Peptides; C026066:enterotoxin A, Staphylococcal; C031818:enterotoxin B, staphylococcal
SEA; SEB; Staphylococcus aureus enterotoxins; UPLC-ESI-MS/MS; milk