Alheira is a traditional sausage that is linked to the culture and customs of the people of the Trás-os-Montes Portuguese region, whose manufacturing records date back to the 15th century. Currently, the production of alheiras plays an important role in the regional and national economy, so it is very important to study and characterize the physicochemical and microbiological properties to ensure the quality of traditional alheiras. Thus, this work had two main objectives: (i) to study the physicochemical and microbiological characteristics of alheiras throughout the manufacturing process of sausages elaborated by two artisanal producers, one in BRAGANÇA and the other in VINHAIS; and (ii) to construct a quality map, taking into account the physicochemical and microbiological characteristics of artisanally produced alheiras. In order to achieve objective 1 (Study 1), samples were taken, consisting of five sausages from three sampling points, three batches from the VINHAIS producer and two batches from the BRAGANÇA producer. The three sampling points were made on the day of stuffing, in the middle of the maturation process and at the end of the maturation process. For objective 2 (Study 2), a sampling scheme of artisanal sausages produced and marketed in the region of Trás-os-Montes was designed. Five alheiras were acquired from fifteen regional producers, however only the results of six producers are presented in this thesis, since the pandemic COVID-19 prevented us from completing the laboratorial analyses in time for the conclusion of this dissertation. The results of Study 1 revealed that the alheiras from the BRAGANÇA producer had a higher (p$<$0.05) water activity (0.991 versus 0.985) and moisture content (51.9 versus 48.9%) and lower (p$<$0.05) pH (5.42 versus 5.54) than that of VINHAIS producer. As expected, during the maturation process, a decrease (p$<$0.05) in these parameters was observed, so that the minimum values were obtained in the sausages ready for commercialization. On the other hand, in the proximate composition, the alheiras from the producer of BRAGANÇA had higher (p$<$0.05) contents of crude protein (9.82 versus 9.40%) and ashes (1.47 versus 1.40%) than the alheiras from the VINHAIS producer. The crude fat content did not differ (p$>$0.05) between producers (22.7 versus 22.5%) and those from VINHAIS producer had a higher (p$<$0.05) carbohydrate content (14.2 versus $17.8$%). The microorganisms evaluated in this work were mesophiles, coliforms, Escherichia coli, Staphylococcus aureus, Clostridium perfringens and Salmonella spp. The alheiras from the producer of BRAGANÇA showed higher counts of mesophiles ($6.69$ versus $5.45$ log ufc/g) and S. aureus ($3.34$ versus $2.90$ log ufc/g) than those of the producer of VINHAIS. The sausages from both producers showed low counts of coliforms, E. coli and C. perfringens. It should also be noted that Salmonella was detected in four out of the 75 analyzed. Throughout the maturation process, the counts of all microorganisms increased gradually. The results of Study 2 evidenced a high variation in the physicochemical parameters studied among the sausages of the different producers, the pH varied between $3.39$ and $4.62$ and water activity between $0.974$ and $0.991$. All of the analyzed sausages had mesophiles counts above $6.5$ log cfu/g. The principal component analysis identified two components that explained $55.5$% of the variation in the $11$ original variables. It should be noted that the three pathogenic microorganisms analyzed, Salmonella, S. aureus and C. perfringens were positively correlated with each other, which indicates that poor hygiene conditions and poor manufacturing practices are responsible for the incidence of these pathogenic microorganisms. Artisanally produced alheiras have high variability in physicochemical and microbiological characteristics, which can negatively impact their level of stability and safety. For the valorization of these typical products, appropriate standards of manufacturing process and good hygiene practices should be followed at all stages of production by artisanal producers.
