1. Introduction

Microbal foodborne diseases are a constant concern to human health, as shown by annual statistics published by official institutions (http://​www.​cdc.​gov/​foodborneburden/​; http://​www.​efsa.​europa.​eu/​en/​efsajournal/​pub/​3129.​htm). The globalization of the food market and the large-scale distribution and processing of raw materials and food products create new ecological niches to which microorganisms from different regions of the world may adapt, raising new problems that the food industry must solve. This trend increases as the food chain tends to be more complex in several ways, including transportation distance, processing steps, distribution of raw materials, and shelf life extension of the finished products. The increase of the more susceptible populations (e.g., the young, elderly, and immunocompromised individuals), the migration of populations from rural to urban areas, the overexploitation of natural resources (such as soil and water) and the climatic changes, are also factors to be taken into consideration. The food industry also has to satisfy the newer consumer habits. In the past years, there has been a growing demand of consumers for foods that are fresh-tasting, lightly preserved, ready-to-eat, and (possibly) with health-promoting effects. Consumer organizations are also more and more concerned about the quality of foods and the ways in which they are produced.