Microbiological and Physicochemical Assessment of Artisanally Produced “Alheira” Fermented Sausages in Northern Portugal

Abstract

Alheira is a traditional non-ready-to-eat sausage produced mainly in northern Portugal. The objective of this study was to evaluate the associations between some relevant physicochemical and microbiological attributes of alheiras produced by different regional producers. Finished products from 8 regional factories amounting to 40 samples were analyzed. Counts of mesophiles, lactic acid bacteria, Staphylococcus aureus, presumptive Clostridium perfringens, and Salmonella spp., as well as pH, water activity (aW), and proximate analysis were determined. Principal component analysis (PCA) of these variables was conducted to construct quality maps. Three meaningful components were extracted, accounting for 63% of data variability. PC1 (26% data variability) was positively associated with LAB, mesophiles, and S. aureus, characterizing therefore longer fermentation. PC2 (22% data variability) correlated negatively with moisture, aW and positively with C. perfringens, and thus has been linked to greater dehydration of sausages. PC3 (15% data variability) correlated positively with pH and protein content, implying the use of more meat in the formulation. This preliminary work has identified three quality factors underpinning the variability in artisanal alheiras; and has also highlighted the need to implement better microbiological control and process standardization during the production of artisanal alheiras.

Genetic Identification and Technological Potential of Indigenous Lactic Acid Bacteria Isolated from Alheira, a Traditional Portuguese Sausage

“…The microbiological quality of these sausages was determined, and the mean AMC results were 8.80 ± 1.58 log CFU/g. Similar results were obtained from previous research, such as 8.42 ± 1.26 [5], 8.5 ± 0.6 [12], and 8.28 ± 0.67 [13]. AMC is a generic test for mesophiles-that grow at temperatures in the range of 25 to 40 • C. A research study [38] compared the alheira microbiological analysis results with the guidelines of microbiological quality for ready-to-eat foods [43].…”

“…The samples (25 g) were homogenized in 225 mL buffered peptone water and ten-fold dilutions were prepared thereof. The aerobic mesophilic count (AMC) was determined in plate count agar (Liofilchem, Teramo, Italy) at 35 • C ± 1 • C for 48 ± 2 h. Previous reports on AMC demonstrate its positive correlation with LAB counts [5,[12][13][14].…”

“…Regarding the protein content as an example, the producers with a lower amount of meat in the recipe used a high amount of fat, a typical case is the sausages manufactured by the AG producer that had a mean protein content of 13.15% and a mean fat content of 48.86%, whilst BV producer sausages were composed of 28.64% of meat and 34.75% of fat. Previous research on the nutritional value of alheira sausages has reported an average protein and lipid content of 15% and 35%, respectively [1][2][3][4][5]14].…”

“…These variations stem from differences in the initial formulation, particularly in the quantity and type of meat (such as various carcass parts and different animal meats) as well as variations in fat and bread content. Other quality factors associated with differences in alheira composition are the duration of fermentation and the extent of drying [5].…”

“…LAB associated with food are generally restricted to the genera Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus, Tetragenococcus, Vagococcus, and Weissella [6]. LAB have been found to be the dominant microorganisms in alheira [5,7]. Importantly, LAB strains, utilized as starter cultures or those developing spontaneously during meat fermentation, must display specific and discernible metabolic attributes.…”