T8-06 Geographical Factors Influence the Spatio-temporal Distribution of Listeria monocytogenes in Natural Environments of New York State

Tuesday, July 24, 2012: 2:45 PM
Ballroom E (Rhode Island Convention Center)
Travis Chapin, Cornell University, Ithaca, NY
Martin Wiedmann, Cornell University, Ithaca, NY
Peter Bergholz, Cornell University, Ithaca, NY
Introduction:   Agricultural lands in New York State (NYS) and other agricultural producing regions are widely interspersed with areas of natural land cover (e.g., forests, wetlands), which may serve as environmental reservoirs of foodborne pathogens such as Listeria monocytogenes.  However, there is limited data regarding the geographical factors that influence the spatial and temporal distribution of L. monocytogenesin natural environments; hence, the risk these areas pose to agriculture remains poorly understood.

Purpose:   The purpose of this study was to utilize meteorological and landscape data to identify potential reservoirs of L. monocytogenes.

Methods:   Samples from natural environments (e.g., wildlife management areas and national forests) in NYS were analysed for the presence of L. monocytogenes.  Classification trees were constructed using meteorological, topological, and soil properties as predictors.

Results:   L. monocytogenes was detected in 8.8% (65/735) of samples.  Classification trees provided clear rules for dividing sites according to presence or absence of L. monocytogenes.  Meteorological variables served as global predictors of L. monocytogenes presence.  L. monocytogenes presence was more likely during the summer and fall seasons when minimum temperatures did not exceed 13 °C, and when there were less than three freeze-thaw cycles in the eight days prior to sampling.  When the above conditions were met, L. monocytogenes was more likely found in eastern NYS than central NYS.  Alternatively, a surrogate to this rule showed that samples less than 169 m from open water sources were more likely positive for L. monocytogenes.

Significance:   These data contribute to understanding the influence of geographical factors on the spatial and temporal distribution of L. monocytogenes.  The high prevalence of L. monocytogenes suggests that this pathogen can be introduced from natural environments to food-associated environments, and these data will be used to gain further insight into the environmental transmission of L. monocytogenes.