A review of the published quantitative risk assessment (QRA) models of L. monocytogenes
in dairy products was undertaken in order to identify and appraise the relative effectiveness of
control measures and intervention strategies implemented at primary production, processing, retail,
and consumer practices. A systematic literature search retrieved 18 QRA models, most of them
(9) investigated raw and pasteurized milk cheeses, with the majority covering long supply chains
(4 farm-to-table and 3 processing-to-table scopes). On-farm contamination sources, either from
shedding animals or from the broad environment, have been demonstrated by different QRA models
to impact the risk of listeriosis, in particular for raw milk cheeses. Through scenarios and sensitivity
analysis, QRA models demonstrated the importance of the modeled growth rate and lag phase
duration and showed that the risk contribution of consumers’ practices is greater than in retail
conditions. Storage temperature was proven to be more determinant of the final risk than storage
time. Despite the pathogen’s known ability to reside in damp spots or niches, re-contamination
and/or cross-contamination were modeled in only two QRA studies. Future QRA models in dairy
products should entail the full farm-to-table scope, should represent cross-contamination and the
use of novel technologies, and should estimate L. monocytogenes growth more accurately by means of
better-informed kinetic parameters and realistic time–temperature trajectories.
