A rapid and sensitive method has been developed for determination and quantification of
cereulide in cream, rice and pasta. Samples are homogenised after addition of
amylase to cooked rice and pasta, and
cereulide is extracted with
methanol. After the removal of water with
methyl-tert butyl ether/
hexane and evaporation until dryness, no further purification was required before analysis with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Recently, both
cereulide and (13)C6-cereulide has become commercially available at high purities; hence, this method offers a more reliable quantification of positive samples than previous methods using
valinomycin or in-house produced and purified
cereulide as calibration standard. The introduction of
amylase in the sample preparation improves both the extraction yield of
cereulide from positive samples of
starch-rich matrices such as pasta and rice, and the within-laboratory reproducibility of the analytical method. The LoQ of the method is 1.1 ng/g
cereulide with RSDs ranging from 2.6% to 10%. The method is fully validated based on Commission Decision 2002/657/EC, suitable for routine analysis, and has been used to analyse samples from a
cereulide food poisoning outbreak in a kindergarten in Norway.
Cereulide production in different rice and pasta samples was investigated, showing that
cereulide was unexpectedly produced by
emetic Bacillus cereus in all eight pasta and rice samples.