Physicochemical and microbiological quality benchmarking of RTE chouriço sausages produced in Northeastern Portugal

Chouriço de carne is a traditional Portuguese RTE dry-fermented sausage made from wine-marinated pork meat, fat, and seasonings. In Northern Portugal, it is still made by traditional methods, using spontaneous fermentation and old smoking/drying techniques, to ensure microbial safety and the desired organoleptic properties.

This study aimed to evaluate the physicochemical and microbiological properties of chouriço de carne traditionally produced in Northern Portugal and to understand the associations between these attributes. Water activity (a_w), moisture, pH, ash, protein, fat, carbohydrates, counts of mesophiles, lactic acid bacteria (LAB), Staphylococcus aureus, Clostridium spp., and detection of Listeria spp. and Salmonella spp. were determined for 14 producers, in five sausages each. The resulting data were subjected to multivariate analysis.

Principal component analysis (PCA) generated three components which accounted for 60% of data variation: PC1 (26%), positively correlated to moisture and protein and negatively to fat and pH, described sausages with more meat in the formulation; PC2 (19.3%), highly correlated to LAB, characterised a longer/rapid fermentation; and PC3 (14.5%), which was associated negatively to ash, and positively to a_w, and to a lesser extent, to Clostridium spp. and S. aureus, defined sausages with poorer hygiene.

Cluster analysis identified three groups: i) chouriços, with high moisture, more meat and very low pH; ii) sausages with low moisture, more fat, and high pH; and iii) chorizos with high moisture, high in meat but very low in fat, low pH, and improved hygiene.

Factor analysis yielded a three-factor solution that explained 65% of the data; PC1 (23.5%) depicted chorizos with low pH but high moisture, PC2 (20,8%) described sausages with more meat, and PC3 (20,6%) longer/rapid fermentation.

Globally, the results displayed significant variability amongst sausage producers, emphasising differences in recipes, ingredients, and manufacturing practices. Nonetheless, the producers’ between-batch variability highlighted the need for standardising processes and improving microbiological control.