Spores of Bacillus cereus pose a threat to food safety due to their high resistance to the heat or acid treatments commonly used to make food microbially safe. As spores survive these treatments and later resume growth either on foodstuffs or, after ingestion, upon entering the gut they are capable of producing toxins which cause either vomiting or diarrhea respectively. The outer layers of the spore consist primarily of proteins which may serve as potential biomarkers for detection. In order to quantify proteins in the insoluble fraction of the spore coat, a proteomics approach using a QconCAT reference standard was employed which is the first time this is used in a heterogeneous system. This allowed us to determine the abundance of 21 proteins which spanned across three orders of magnitude and together covered 5.66% ±0.51 of the total spore weight. Classification by abundance resulted in functional characterisation of the protein BC_0987, renamed SasS. Furthermore, protein stoichiometry and determination of the abundance of, for instance, germination mediating enzymes provides useful information for model development. And finally, the four most abundant proteins, CotB1, CotB2, CotX and InhA, are presented to be biomarker candidates containing immunogenic epitopes as predicted by the SVMTriP algorithm and being conveniently located in the outermost layers of the spore.