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Identification of quantitative and qualitative patterns of environmental contamination by Listeria spp. and L. monocytogenes in fresh produce processing facilities and evaluation of practical control measures able to eliminate transient and persistent co


Environmental contamination sources have been widely studied but most of the research has not been focused on fresh produce. Well-establish routine Environmental Monitoring (EM) programs should be designed on a risk-based approach, considering the nature and size of the food operation and reflecting aspects related to the raw materials, the production processes and the final product but they also need to be regularly revised based on trend analysis. Current approach to designing environmental monitoring includes zoning and sanitary design but it has been demonstrated that it should also consider location connectivity and ranking with respect to the expected length and level of contamination of a surface. The current proposal aims to contribute generating practical knowledge and solutions for the implementation of EM programs in fresh produce processing facilities as different industrial practices and processing environments may account for different contamination patterns. Three objectives have been identified. The first objective will improve understanding on how different factors interact and affect the probability of contamination in different fresh produce processing facilities by means of a systematic sampling through an EM plan including zoning, sanitary design, location connectivity, and ranking with respect to the length and level of contamination of Listeria spp. In the second objective, the application of whole genome sequencing (WGS) in food processing environments (FPEs) will be used as a tool to enhance the understanding of the origin, cross-contamination, reservoir, and possible persistence of specific Listeria spp./L. monocytogenes isolates. Establishment of the genetic correlations of the Listeria spp./L. monocytogenes isolates will be necessary to understand the distribution patterns across different compartments within the same processing plant and among different industrial practices. Data will be obtained on the distribution of identical or similar Listeria spp./L. monocytogenes WGS sequence types in different locations and times for each processing plant and among facilities. The third objective will focus on the evaluation of control measures currently implemented in the produce processing facilities of the industry collaborators. Observational studies in different processing lines will help to determine the efficacy of different sanitizing procedures against different types of contamination scenarios (transient and persistent). These results will allow the identification of potential strain adaptation to common sanitizers and its impact on the tolerance to different environmental stresses. The current project aims to impact the fresh produce processing industry in several ways including:
i) Development of an improved set of guidance based on empirical data for the industry,
ii) A reduction on the L. monocytogenes contamination in fresh produce processing facilities,
iii) Establishment of common contamination patters within one processing plant and among different processing plants, and
iv) Recommendations on the most efficient sanitizing treatments to eliminate L. monocytogenes from the processing environment.

Allende, Ana; Gill, Maria
CEBAS-CSIC Campus de Espinardo, Spain
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