A new method for rapid and quantitative detection of the Bacillus cereus emetic toxin cereulide in food products by liquid chromatography-tandem mass spectrometry analysis.

The Bacillus cereus emetic toxin cereulide causes foodborne intoxication, which may occasionally result in severe disease, and even death. To differentially diagnose the emetic-type of foodborne disease caused by B. cereus and assess the safety of commercial food, we developed a rapid method to quantitate cereulide. This method was combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis for the extraction of cereulide from food using a normal-phase silica gel cartridge. The limits of detection and quantification were 0.1 and 0.5 ng of cereulide ml(-1), respectively. Spiked cereulide was reproducibly recovered with over 67% efficiency from nine diverse foods implicated in cereulide food poisoning. The recovery rate, reproducibility, and intermediate precision for this single laboratory validation using boiled rice were 87.1%, 4.4%, and 7.0%, respectively. Further, we detected a wide range of cereulide concentrations in leftover food and vomitus samples from two emetic foodborne outbreaks. LC-MS/MS analysis correlated closely with those acquired using the HEp-2 cell assay, and quantitated cereulide from 10 food samples at least five times faster than the bioassay. This new method will provide clinicians with an improved tool for more rapidly and quantitatively determining the presence of cereulide in food and diagnosing food poisoning caused by cereulide.