Identification of enterotoxin-producing Bacillus cereus strains by MALDI-TOF MS
A research project in cooperation with the Chair of Food Safety at the Faculty of Veterinary Medicine of the LMU Munich
Bacillus spp. are ubiquitous in the environment. They comprise gram-positive, motile and spore-forming rods. The spores are very resistant, i.e. destruction by pasteurisation or processing of raw materials is not sufficient. Some strains are able to form highly toxic enterotoxins.
Image study sheds light on the formation of cereulide
Purely cultural detection of toxinogenic bacteria is not a sufficient measure to assess the risk of food intoxication with enterotoxins. Until now, however, lengthy and complex cell culture tests have been necessary for this. Cereulide is cytotoxic, extremely heat-stable and has a strong emetic effect even after a short incubation period of about 1.5 hours. So far, the enterotoxin has been detected qualitatively and quantitatively by LC-MS/MS. Alternatively, cell culture tests and the capillary migration test are available for indirect toxin detection.
The aim of this study was to verify whether cereulide-forming and non-forming Bacillus cereus strains can be distinguished using MALDI-TOF MS technology. For this purpose, 112 selected B. cereus isolates were measured for cereulide formation in an image study using MALDI-TOF MS.