## 1 Introduction  
Osmotic dehydration (OD) is a well-established food processing technique involving the immersion of food items in a hypertonic solution [1; 2; 3]. The selection of appropriate conditions (such as the type and concentration of the osmotic solute, solution/product mass ratio, temperature, time, pressure, shape and size of the vegetables, agitation level, etc.) depends on achieving effective dehydration within a reasonably short time while preserving the quality characteristics of the food product [3]. In addition, the combination of mild OD conditions and the selective enrichment of the osmosed tissue with solutes of the osmotic solution can produce modified food products with desired quality attributes [4; 5]. The osmotic dehydration process also ensures moisture removal with lower energy consumption compared to the conventional dehydration processes [6]. Its nonthermal nature offers the ability to prolong the shelf life of fruits and vegetables without sacrificing the fresh-like sensory attributes that are commonly associated with the consumption of fresh-cut salads. In most cases, the effect of osmotic dehydration on mass transfer kinetics (during OD)and/or quality characteristics of the dehydrated tissue (after OD and during storage) was studied. The potential use of osmotically dehydrated fruits and vegetables in ready-to-eat (RTE) mixed salad products has not been investigated. The marketing of osmo-dehydrated products (intermediate moisture, ready-to-eat) is limited to fruit products/ingredients used in dairy, candy and bakery industries, as well as utilized in the production of fruit and vegetable concentrates and jams [1]. Ready-to-eat (RTE) mixed salads are fresh cut leafy vegetables subjected to processing such as washing, cutting, mixing, and packaging [7; 8]. Due to rapid urbanization and an increasing demand for healthy, convenient, and diverse plant-based diets, the RTE salads market is growing [9]. In 2022, fresh-cut vegetables represented a global market of USD 346.05 billion [8]. According to a new research report by Global Market Insights, the market for processed fruits and vegetables, including RTE salads, will exceed USD 392 billion by 2025. This advance is attributed to several factors; among them are technological innovations in production that have enabled the development of products with greater nutritional value and longer shelf life (Global Market Insights Inc., Selbyville, DE, USA, 2019) [10]. In terms of composition and nutritional importance, RTE salads are low in calories, rich in fiber, vitamins, minerals, antioxidants, and other phytochemicals [11; 12; 13]. However, they are highly perishable with a storage life of about 7-10 days under refrigeration at temperatures \(\leq\) 5 \({}^{\circ}\)C [14; 15]. The shelf life of RTE salads is determined using microbial and chemical changes. The complex indigenous spoilage flora of RTE salads comprises _Pseudomonas_, lactic acid bacteria, _Enterobacteriaceae_, yeasts and molds. Other causes of quality degradation include browning and enzymatic softening, which may also partially be attributed to enzymes released by microorganisms [15]. A limited number of models that describe the effect of processing and storage conditions on the quality and the microbial risk in RTE fresh-cut vegetables has been reported [16; 17; 18; 19; 20]. A challenge for food scientists is to explore the potential of preserving the quality and extending the shelf life of RTE salads [8; 21; 22]. Spinach (_Spinacia oleracea_ L.) is one of the most common leafy vegetables present in RTE salads, well recognized as a functional food owing to its diverse nutritional composition, including lipophilic (such as carotenoids and chlorophylls) and hydrophilic bioactive compounds (such as flavonoids and phenolic acids) [23; 24]. It is consumed raw, minimally processed (in RTE salads), boiled, canned, frozen or in other food formulations.