Prof. Paula Teixeira and her postdoc Vania Borges Ferreira published a paper in the Journal of Food Protection that became, with 340 downloads, the most popular item of the year in this scientific journal. This visibility naturally reflects both the importance of the topic as the quality of work. Listeriosis is an infection whose origin ingestion of food contaminated with Listeria monocytogenes bacteria and is proving to be an important public health problem due to the severity of the disease and its significant economic impact. Although it is a rare disease with a relatively low incidence, listeriosis has the highest mortality rate of all foodborne diseases under surveillance in the European Union.

In countries with established surveillance programs for listeriosis has been registered an increase in its incidence and a change in the distribution of cases, with an increase in individuals aged over 60 years. In recent years several studies have suggested that the persistent strains of L. monocytogenes in food processing environments for several months or even years is an important factor, not only in food contamination and in the transmission of this pathogen to people. Typically, persistence is identified by re-isolation of a molecular subtype of samples taken at a particular location over time. Technical and environmental factors, such as equipment and hard to reach places and hygiene, have been identified as key elements for this persistence.

The specific mechanisms that caused it are still poorly understood. Although some studies indicate that persistent strains of L. monocytogenes have specific phenotypic characteristics that enhance the persistence (such as biofilm formation and better adaptation to unfavorable environmental conditions), other studies point to the absence of significant differences between persistent strains and isolates sporadically. This review article in the Journal of Food Protection analyzes and discusses the current scientific knowledge about the persistence of L. monocytogenes, with particular focus on (i) persistence in associated habitats and food processing, (ii) persistence in the environment in general, ( iii) phenotypic and genotypic characteristics of persistent strains, (iv) niches, and (v) the impact of persistence in the economic and public health. Those interested in reading the article should contact Vania Ferreira.