## 1 Introduction  
Dry-cured sausages are well-appreciated meat products usually produced by mixing ground meat with seasonings, stuffing, and ripening. It is a common industrial practice to also include some synthetic additives, such as nitrites, to improve microbial stability and safety, color, and flavor [1]. However, new trends in consumers' preferences are leading to an increased demand for additive-free meat products. In recent years, several attempts have been made to substitute synthetic additives with natural products, such as parsley, celery, card, and red wine, although, at the moment, no alternatives for nitrites that fulfil simultaneously all of nitrite's functions (for example in color and flavor development, the oxidative status, and the antimicrobial effect) have been found [2]. Among the natural products that could improve the quality of meat products, as well as enrich them in healthy compounds, such as phenols [3], several by-products are receiving increased attention in the food industry. Grape by-products, produced in large quantities in the winery industry, have been extensively researched [4; 5; 6]. They have been assayed in food systems as a source of dietary fiber, colorings, and antioxidants [4; 5; 6; 7]. Theseby-products are rich in phenols, which have a beneficial effect on human health [8] and, when added to food systems, have relevant antioxidant and antimicrobial activities [6; 9; 10]. These activities might be useful to reduce the use of synthetic additives in meat products, which has been the topic of recent research [11]. The addition of both white grape by-products (usually before fermentation) and especially red grape by-products (usually after fermentation) has recently been researched in some meat products. In burgers, red grape pomace provided burgers enriched in phenols but a loss in the overall acceptability [12], and it was proposed as an alternative in burgers to ascorbate to successfully preserve \(a^{\ast}\) and prevent lipid and protein oxidation [13], to salt to control microbial spoilage [14], to sulfites against radical formation and myosin heavy chain crosslinking but not against thiol loss [15], and to erythorbate to increase the oxidative stability and preserve \(a^{\ast}\)[16]. In beef sausages, red grape pomace was suitable to partially substitute nitrites in terms of lipid oxidation, without causing a loss in acceptability [11]. In dry-cured sausages, grape-pomace-based extracts have been essayed to substitute nitrites, resulting in a similar prokaryotic community [17] and without differences in lipid oxidation but a loss in color but not in the aroma profile [18], as well as to enrich the sausages in health-beneficial phenols [3] and to replace fat [19]. However, some of these studies have not researched the effect on the microorganisms present in the product. Grape pomace, the main by-product from the winery industry, is composed of skins, seeds, stems, and the remaining pulp. It contains large quantities of water and microorganisms that reach high counts quickly [20; 21], as well as active enzymes, which lead to rapid spoilage. To overcome these issues, grape pomace is usually processed prior to its use in the food industry. This usually involves seed separation and solvent extraction, with the corresponding waste generation, or drying. Drying is the simplest and traditional process for rendering pomace into a safe and stable product. However, it can cause the loss of thermolabile bioactive compounds [22; 23]. Contrarily, the application of non-thermal technologies, such as high hydrostatic pressure (HHP), is an alternative to stabilize the by-products with minimal losses [24]. Recently, HHP combined with blanching has been proposed to stabilize red [25] and white grape pomace [20], facilitating its integral use without extraction, drying, or irradiation. HHP, a non-thermal treatment, decreases the microbial counts without causing losses in the phenol content, and thermal blanching inactivates enzymes, such as polyphenoxidase [20; 21].