Quantitative proteomics of food pathogenic Bacilli - a quest for biomarkers

Food manufacturers have a variety of methods at their disposal to ensure foods are microbially safe. However, due to increasing demands from consumers for minimally processed foods the severity of these treatments is frequently mild. Frequently being able to survive such treatments, bacteria of the genus Bacillus present a pressing issue. Comprising spore-forming, Gram-positive, aerobic or facultative anaerobic bacteria the genus contains a group of pathogenic bacteria known as Bacillus cereus sensu lato. Spores are a metabolically dormant, extremely resistant cell type capable of surviving in extreme environments The mild treatments used in the food industry used to eliminate bacteria are then unable to kill or inactivate spores present.
To detect Bacillus cereus and ensure food safety, current ISO guidelines (ISO 7932, ISO 21871) are based around incubation on agar plates for 24 hours or even longer. Developing a platform for direct detection of spores would allow for better, faster and ultimately cheaper detection methods but this requires proper spore biomarkers. This biomarker needs to be robust and specific to the system, be abundant enough to have reliable interaction with the sensor, and be accessible to the receptor molecule of the sensor it is supposed to bind to.
The outermost layers of the spore, the inner coat, outer coat and exosporium, primarily consist of proteins. Therefore we set out to identify and quantify the proteome of spores of food pathogenic Bacilli, as well obtain information on protein localisation within in the spore.