a b s t r a c t
Mathematical description of the behavior of bacterial foodborne pathogens and concepts of risk
assessment were first applied to spore-forming bacteria and specially to Clostridium botulinum with
numerous works dealing with spores heat destruction to ensure the safety of canned foods or with their
germination and growth probability in foods. This paper discusses two aspects which appear specific to
pathogenic sporeformers in comparison to vegetative microorganisms, that is, firstly, the extreme intraspecies
biodiversity of spore-forming bacteria and its consequences for risk assessment and, secondly,
the modeling of spore germination and outgrowth processes. The intra-species biodiversity of sporeforming
bacteria has a great impact on hazard identification, exposure assessment and hazard characterization
leading thus to an extremely variable individual poisoning risk for consumers. The germination
and outgrowth processes were shown independent at the single cell level and although numerous
studies were performed to study the effect of spores treatments and growth conditions on these two
events, the mathematical modeling and the prediction of these processes is still challenging today. The
difficulties to accurately assess the biodiversity and the germination and outgrowth processes of sporeforming
bacteria lead to a substantial uncertainty in risk estimates related to the exposure to these
microorganisms. Nevertheless, significant progress have been made these last years improving the
relevance of quantitative risk assessments for spore-forming bacteria and decreasing the risk uncertainty.
Despites these difficulties, risk assessment still constitutes a valuable tool to justify the implementation
of management options.