The study evaluated the potential of Thymus mastichina, Lavandula luisiery, and Origanum virens hydrolates—essential oil-rich species found in the Dehesa ecosystem—as natural agents for pork preservation through marination. Hydrolates, the main by-products of essential oil distillation, were characterized by their volatile composition, total phenolic content, antioxidant capacity, and antimicrobial activity against Escherichia coli and Listeria innocua. Pork fillets were marinated (24 h) with increasing hydrolate concentrations (1:1, 1:1.5, 1:2 w/w) and then stored for eight days under refrigeration to assess microbial growth, oxidation, and color changes. All hydrolates exhibited similar antimicrobial effects, though Origanum showed the highest phenolic content and antioxidant activity. Marination had limited antimicrobial impact. Marination with Origanum and Thymus provided significant protection against lipid oxidation during storage, while Lavandula displayed limited or even pro-oxidative behavior at certain doses. Marination did not affect carbonyl formation although it caused slight changes in instrumental color. Overall, the study highlights the potential of Lavandula, Thymus, and Origanum hydrolates as sustainable alternatives to synthetic antioxidants in meat products, emphasizing their antioxidant—rather than antimicrobial—effect.

High hydrostatic pressure (HHP) can extend the shelf life and ensure safety of meat products such as lamb burgers. Lupinus albus variety Orden Dorado (a low alkaloid content variety) flour, rich in protein and phenolic compounds, offers the potential to enhance the preservation of meat products during storage. Lamb burgers were formulated with Lupinus albus flours (1%, w/w; weight/weight), either conventional or obtained by compression milling, and processed by HHP treatments (untreated, two consecutive cycles at 600 MPa for 1 s; or a single cycle at 600 MPa for 4 min), with the total processing time using the HHP unit being the same for both. Then, they were subsequently stored for 14 days under refrigerated conditions. Proximate composition, microbiological changes, color, and oxidation of burgers during storage were evaluated. Flour obtained by compression milling presented higher phenolic compound content, while its antioxidant activity is similar to that obtained by conventional methods. In lamb burgers, the incorporation of both lupine flours maintained the proximate composition and fatty acids profile. Lipid oxidation after 14 days was significantly lower in burgers with lupine flour obtained by compression milling, whereas protein oxidation responses depended on treatment–formulation interactions. HHP drastically reduced microbial counts, with sustained inactivation of coliforms and Escherichia coli (E. coli) although instrumental color was significantly altered in fresh burgers after processing. However, sensory scores of grilled burgers remained unaffected by either flour type or HHP treatment. Incorporation of Lupinus albus flour into lamb burgers processed by HHP preserved sensory quality while enhancing the microbial and lipid oxidation stability of burgers. Finally, the application of two short (1 s) cycles at 600 MPa was more beneficial than a single 4 min cycle, offering similar microbial inactivation with less impact on the quality changes in burgers. Finally, applying two short (1 s) HHP cycles at 600 MPa was more beneficial than a single 4 min cycle, as it achieved similar microbial inactivation while better preserving the color and oxidative stability of the burgers.