Purpose: The aim of this study is to gain a more complete understanding of the differences in the environmental distribution and ecology of distinct Listeria spp. Data from this study will specifically provide insights on the usefulness of Listeria spp. as an indicator of L. monocytogenes contamination in the produce preharvest environment.
Methods: Geo-referenced environmental samples from natural areas and produce fields in New York State (NYS) were analyzed for the presence of L. monocytogenes and other Listeria spp. Classification trees were developed using remotely sensed data to determine spatial and temporal predictors of Listeria spp.
Results: In the produce preharvest environment, the prevalence of L. monocytogenes and other Listeria spp. (e.g., L. innocua, L. seeligeri, and L. welshimeri) were 15% (88/588) and 28% (165/588), respectively. Proximity to water, impervious surfaces, and pastures; soil moisture; and temperature were factors that predicted the prevalence of L. monocytogenes in the preharvest environment. Similar factors predicted L. innocua (water and pasture proximity; frost/thaw cycle) and L. seeligeri (urban, pasture, and water proximity; soil moisture). In natural areas, the prevalence of L. monocytogenes and other Listeria spp. (i.e., L. innocua, L. marthii, L. seeligeri, and L. welshimeri) were 8% (59/734) and 28% (206/734), respectively. Temperature, pasture proximity, and frost cycles predicted the prevalence of Listeria species in natural areas.
Significance: Our data demonstrate widespread presence of Listeria species in natural areas and the preharvest environment (approaching 30% prevalence) and identify ecological factors that affect the prevalence of different Listeria species.