## 1 Introduction  
Ready-to-eat food (RTE) is a type of product that must not be cooked or reheated before serving. This includes salads, vegetables, fruits, cooked meats, smoked fish, desesters, sandwiches, cheese and food that are previously cooked in order to be later served cold. The trend towards consumption of minimally processed, ready-to-eat, refrigerated and frozen food products poses new problems to the identification and management of bacterial risks for consumers, mainly due to the inability to maintain a temperature-controlled environment. Even if properly stored, RTE foods can contain high risk ingredients that allow pathogens to grow and multiply. Recent modifications in food production and processing practices and the ever-changing eating habits of the consumers, who appreciate the readiness of RTE foods, have affected the incidence of pathogens that can multiply in such foods. This typology of foods presents more safety and quality complications, because of their susceptibility to bacterial contamination, for the absence of the adequate preservatives and storage temperature during the food chain. These products are usually characterized by a long shelf life at refrigerated temperature and they can be contaminated with spoilage bacteria and foodborne pathogens during all stages of the production process. Like many types of RTE food, sandwiches are tasty and easy to eat, especially for workers who are always in a hurry and eating meals away from home. Sandwiches are a popular RTE food typology that can contain some high-risk ingredients, such as raw vegetables, eggs and salad dressings, and whose preparation usually involves manual handling, which increases the number of potential contamination sources. Many pathogenic bacteria like _Listeria_,Staphylococcus, Shigella, Yersinia spp., ubiquitous bacteria found in many environments like soil or water, can come into contact with these raw or fresh ingredients [1]. Many human pathogens can also be transmitted through bare-hand handlings, like _S. aureus_, which can be found on human skin and hair, or other pathogens colonizing the intestinal tract. The multi-ingredients used for the production and the sandwich fillings like cheese, chicken, eggs, ham, salad, sauce, and various types of fresh produce contribute to the microbial contamination and have been associated with foodborne illness outbreaks, the last reported in the UK in 2019, where hospitalized patients died after the consumption of sandwic contaminated by _Listeria monocytogenes_[2]. The RTE foods preservation techniques are based on low temperatures, which do not prevent some psychrotrophic bacteria from multiplying at refrigeration temperatures, such as _L. monocytogenes_, a ubiquitous Gram-positive genus that can be isolated from a wide range of food products [3]. This psychrotrophic pathogen may be already present in raw materials, but the risks associated with the consumption of RTE foods [4] could also be due to their presence in processing plant equipment and cross-contamination during the food storage at refrigeration temperature [5]. _L. monocytogenes_ is the most important specie responsible for food-borne outbreaks and severe illness, listeriosis, mainly in elderly consumers, immunocompromised individuals and pregnant women [6], even if other species like _L. ivanovovii_ and _L. seeligeri_ have been found in sporadic cases. _L. ivanovovii_ has been isolated, although rarely, from infected humans, indicating a pathogenic potential for humans [7]. Although, _L. seeligeri_ carries a virulence gene cluster that is not expressed, it has been associated with rare cases of infections in humans [8; 9].  
The objective of the present investigation was to examine the microbiological quality of 24 ready-to-eat sandwic, to evaluate the risk for consumers due to the presence of pathogenic strains, and the presence in the isolates of antibiotic resistance and other virulence factors.