P3-37 Yersinia enterocolitica in Fresh Vegetables: Evaluation of the Persistence during the Storage and the Effectiveness of the Washing Treatment

Tuesday, July 28, 2015
Hall B (Oregon Convention Center)
Elisabetta Delibato
Federico Capuano , Istituto Zooprofilattico Sperimentale del Mezzogiorno , Portici , Italy
Eleonora Pucci
Dario De Medici , Istituto Superiore di Sanità , Rome , Italy
Introduction: Over the past few decades, leafy fresh vegetables have been increasingly recognized as significant reservoirs of foodborne pathogens. Contaminated Vegetables with Yersinia enterocolitica and cases of yersiniosis, epidemiologically correlated with the consumption ready to eat (RTE) vegetables, are recently well documented in Europe.

Purpose: The aim of this work is to evaluate (1) the survival of Y. enterocolitica along the entire shelf life of fresh leafy vegetables and “Ready-to-Eat” (RTE) vegetables, and (2) the effectiveness of different washing treatments to reduce contamination of Yersinia enterocolitica on the surface of leafy vegetables.

Methods: Leafy vegetables were spiked with different concentration of pathogenic Yersinia enterocolitica (bio-serotypes O:3/4), stored at refrigerator temperature for six days and daily analyzed. Other spiked leafy vegetables were submitted to different domestic washing treatments (water, sodium hypochlorite at 60 and 220 ppm). All the samples were analyzed using both ISO 10273 standard cultural method and real-time PCR method.

Results: The results demonstrated that the concentration of Yersinia enterocolitica, detected on the surface of vegetables, does not decrease even when they were stored at refrigerator temperature for a week. Only the washing with 220 ppm of sodium hypochlorite can guarantee the 1-logarithm reduction of the original contamination of Y. enterocolitica in the vegetables.

Significance: Yersinia enterocolitica could persist in the vegetables for the entire shelf life and its presence could not be completely eliminated using domestic or industrial washing practices. The application of good agricultural practices and HACCP system, also in primary production, are the only measures to reduce or eliminate biological contaminants and achieve the objective of food safety in RTE vegetables.

Acknowledgment: This work was supported by the National project “Ricerca Finalizzata 2009 (RF-2009-1538880)”