Traditional Dry Fermented Sausage Research Articles

Biogenic amines content in traditional dry fermented sausage Petrovská klobása as possible indicator of good manufacturing practice

The aim of this study was to determine the content of nine biogenic amines (tryptamine, phenylethylamine, putrescine, cadaverine, histamine, serotonin, tyramin, spermidine and spermine) and total biogenic amines in traditional dry fermented sausage Petrovská klobása at the end of drying period, as possible indicators of good manufacturing practice (GMP).Chromatographic separation of dansyl chloride derivatizated amines was completed in 8 min. Analyses were performed by HPLC-DAD on Eclipse XDB-C18 column. Tryptamine and spermine were determined in all analyzed samples, while histamine, serotonin and spermidine were not detected in any samples. Average content of individual biogenic amine ranged from 5.54 mg/kg (putrescin) to 75.1 mg/kg (tryptamine) and total content of biogenic amines varied from 77.8 mg/kg to 174 mg/kg.The results obtained in this study provided no evidence for deviations from good manufacturing practice in Petrovská klobása production.

Polycyclic aromatic hydrocarbons incidence in Portuguese traditional smoked meat products

Meat and meat products safety is, nowadays, a priority quality requirement with chemical hazards having a great impact. Amongst the residues and contaminants, polycyclic aromatic hydrocarbons (PAHs) can be of particular concern, namely in those products having direct smoking during processing. In order to investigate the contamination levels in traditional dry fermented sausages manufactured in Alentejo (South of Portugal), 66 samples were collected from regional producers. PAH8 represented less than 0.5% of the total contamination profile, with benzo[a]anthracene and chrysene being the most concentrated compounds (maximum contents of 7.53 and 8.9μgkg−1), irrespective of the product type analysed. Benzo[a]pyrene content varied between 0.21 and 1.00μgkg−1, with only one sample showing this maximum content. Blood sausages were potentially more risky, since total PAH8 contents were generally higher and because its presence in inner parts were significantly superior than that found in casings, comparatively to meat counterparts, which expressed superior benzo[a]pyrene toxic equivalents.

Air mycopopulations in Petrovská klobása producing facility

Different types of filamentous fungi periodically cause problems in small-scale facilities for traditional dry fermented sausages, such as Petrovsk? klob?sa from Vojvodina province (Serbia). Mould contamination can be observed during processing, ripening, and storage. Sausages may become spoiled due to visible mould colonies on the surface and off-flavours they produce. The most important - if mycotoxin production occurs it might promote a number of health disorders. Knowledge and control of filamentous fungi are, therefore, essential to produce sausages that satisfy the criteria of hygienic quality, sensorial characteristics, and food safety. The aim of this study was to survey mycoflora of a small-scale facility producing traditional dry fermented sausage - Petrovsk? klob?sa. The mould contamination of the air in processing unit and ripening chambers was investigated, in order to determine the important fungi in terms of spoilage of the products and ability to produce mycotoxins. The mould contamination of air in processing unit and ripening chambers examined was in range 0.22 - 1.89 log CFU/P.d. Isolated moulds belong to 6 genera: Aspergillus (3 species), Cladosporium (1 species), Eurotium (2 species), Fusarium (1 species), Penicillium (12 species) and Scopulariopsis (1 species). The most abundant were species of Penicillium genus, many of which are capable for mycotoxin production. The level and diversity of fungal contamination of air varied between samples, influenced by the general hygiene, the buildings, the airflow, the outdoor environments, and the time of year. This knowledge is crucial for the improvement of hygiene control systems in small-scale processing units.

Antioxidant and angiotensin-I converting enzyme inhibitory activity in the water-soluble protein extract from Petrovac Sausage ( Petrovská Kolbása)

Petrovac Sausage ( Petrovská Kolbása) is a traditional dry fermented sausage from Bački Petrovac (province Vojvodina, Serbia). In this study, the in vitro antioxidant and angiotensin-I converting enzyme (ACE) inhibitory activities in the water-soluble (pH 7.4) protein extracts were evaluated throughout the sausage ripening. In the protein extract from the sausage mixture (day 0) degree of hydrolysis (DH) of 6.07 ± 0.84% was determined, which reached 17.71 ± 0.76% after 90 days. The protein extract at day 0 showed free radical (2.2-diphenyl-1-picrylhydrazyl, DPPH ) scavenging assay (RSA) and reducing power (RP) of 27.61 ± 0.73% and 0.493 ± 0.016, respectively. In fermented sausage at day 90, RSA and RP increased up to 50.08 ± 1.25% and 0.972 ± 0.065%, respectively. The examined protein extracts exhibited ACE inhibitory activity, which also enhanced; from 27.11 ± 2.163% (day 0) to 73.74 ± 3.299% (day 90). These results suggested that in Petrovská Kolbása, the final products of meat proteins hydrolysis during sausage ripening might be hydrolysates with antioxidant and ACE inhibitory properties.

Physicochemical, biochemical and sensory properties for the characterization of Petrovská klobása (traditional fermented sausage)

A study was carried out on a typical homemade Petrovsk? klobas? in order to characterize this traditional dry-fermented sausage, to provide a basis for establishing the quality standard and protecting designation of origin. This paper reviews the chemical composition, some physicochemical, proteolytic and sensory parameters of Petrovsk? klobas? made by five manufacturers chosen as representatives. Beside the differences between sausages made by different manufacturers the main properties of this traditional product were though recognized. Compared to other dry-fermented sausages Petrovsk? klobas? is characterized by a high content of protein (23.36-30.45%) and low contents of NaCl (2.99-3.28%). With some minor exceptions, the values of other chemical parameters are within the range of those observed for various dry-cured sausages. Weight loss during the processing is high (up to 45.71%) and pH value (~ 5.4) corresponds to the values for this parameter in other European traditional fermented sausages. Contents of different nitrogen fractions show that Petrovsk? klobas? undergoes significant proteolytic changes. At the end of ripening, Petrovsk? klobas? is characterized by aromatic and spicy-hot flavor, dark-red color and hard consistency.

Safety improvement and preservation of typical sensory qualities of traditional dry fermented sausages using autochthonous starter cultures

Traditional dry fermented sausages are manufactured without addition of starter cultures in small-scale processing units, their fermentation relying on indigenous microflora. Characterisation and control of these specific bacteria are essential for the sensory quality and the safety of the sausages. The aim of this study was to develop an autochthonous starter culture that improves safety while preserving the typical sensory characteristics of traditional sausages. An autochthonous starter composed of Lactobacillus sakei, Staphylococcus equorum and Staphylococcus succinus isolated from a traditional fermented sausage was developed. These strains were tested for their susceptibility to antibiotics and their production of biogenic amines. This starter was evaluated in situ at the French traditional processing unit where the strains had been isolated. Effects of the autochthonous starter were assessed by analysing the microbial, physico-chemical, biochemical and sensory characteristics of the sausages. Inoculation with the chosen species was confirmed using known species-specific PCR assays for L. sakei and S. equorum and a species-specific PCR assay developed in this study for S. succinus. Strains were monitored by pulse-field gel electrophoresis typing. Addition of autochthonous microbial starter cultures improved safety compared with the traditional natural fermentation of sausages, by inhibiting the pathogen Listeria monocytogenes, decreasing the level of biogenic amines and by limiting fatty acid and cholesterol oxidation. Moreover, autochthonous starter did not affect the typical sensory quality of the traditional sausages. This is the first time to our knowledge that selection, development and validation in situ of autochthonous starter cultures have been carried out, and also the first time that S. equorum together with S. succinus have been used as starter cultures for meat fermentation. Use of autochthonous starter cultures is an effective tool for limiting the formation of unsafe compounds in traditional sausage while preserving their original and specific sensory quality.

Modeling the Aminogenic Potential of Enterococcus faecalis EF37 in Dry Fermented Sausages through Chemical and Molecular Approaches

Amino acid decarboxylase activity of the Enterococcus faecalis strain EF37 was monitored during fermentation and ripening of a traditional dry fermented sausage from Northern Italy (Salame Veronese) by means of microbiological, chemical, and molecular approaches in relation to three technological factors: fermentation temperature, sodium chloride concentration, and amount of glucose added to the meat mixture. Besides the analytical determination of tyramine and phenylethylamine accumulation and the counts of enterococci, the presence and quantification of the tyrosine decarboxylase gene (tdc) and its mRNA transcript were also investigated by using real-time PCR. According to the mathematical models obtained, all of the three factors studied were statistically significant and microbiologically relevant for the early development of enterococci, although the fermentation temperature had a more relevant influence on the enterococcal viable cells of the ripened product. Sodium chloride concentration was the most determinant factor of the final tyramine and 2-phenylethylamine accumulation and also of the levels of tdc present in the final product. In contrast, an effect of glucose concentration on tdc expression was observed in the last period of ripening. Moreover, increasing amounts of sodium chloride and decreasing fermentation temperature resulted in a reduced tdc expression. This is the first time that bacterial tyrosine decarboxylase potential is directly examined through a molecular approach in a fermented meat. The quantification of tdc and its transcript can help to elucidate the critical steps and factors during food manufacturing at which bacterial aminogenesis is possible, thus allowing researchers to propose technological measures to control decarboxylase activities.

Consumers’ behaviour toward typical Italian dry sausages

This study aimed to provide information on handling and consumption habits of dry fermented sausages produced in Italy with traditional methods. Traditional sausages are considered by interviewed consumers as an important part of their habits. The habitual purchase was widespread in the considered regions and it was made often directly from the producers. Handling and consumption habits were linked with the typology of sausages and therefore to the territory. Statistical analysis allowed to identify three categories of consumers. The first included the majority of the consumers that handled, ate and stored dry sausages as ‘laid down’ by the tradition and it was named “traditionalist”. The second group was composed by “nostalgic” people because they associated the consumption of dry sausages with the tastes of the ‘olden days’. The third contained “modern consumers”: they did not buy traditional sausages regularly, and they managed the product in ‘new ways’. In conclusion, this survey has made possible to understand consumers’ behaviour and the factors influencing their choices in the purchase of traditional dry fermented sausages in the surveyed areas.

Microbial Ecology of the Soppressata of Vallo di Diano, a Traditional Dry Fermented Sausage from Southern Italy, and In Vitro and In Situ Selection of Autochthonous Starter Cultures

The microbial ecology of "soppressata of Vallo di Diano," a traditional dry fermented sausage from southern Italy, was studied by using both culture-dependent and culture-independent approaches. The ripened fermented sausages were characterized by high microbial loads of both staphylococci and lactobacilli. Using PCR-denaturing gradient gel electrophoresis (PCR-DGGE) targeting the variable V3 and V1 regions of the 16S rRNA gene and direct DNA sequencing, it was possible to identify Staphylococcus xylosus, S. succinus, and S. equorum among the staphylococci and Lactobacillus sakei and L. curvatus within the lactobacilli. Moreover, Debaryomyces hansenii was the main yeast species found by targeting the yeast 26S rRNA gene by PCR-DGGE. Selected strains of S. xylosus, L. sakei, and L. curvatus were characterized for their technological properties in the ripening conditions of the fermented sausages so as to select an autochthonous starter formulation. The selection included the determination of nitrate reductase, lipolytic, and antioxidant activity and proteolysis with myofibrillar and sarcoplasmic protein fractions. Such properties were evaluated in both in vitro and in situ assays; the latter were performed by using each strain as a starter in the laboratory-scale manufacture of soppressata of Vallo di Diano and by monitoring the microbiological and chemical changes at the end of ripening. The results show differences between the in vitro and in situ selection results and indicate that in situ evaluation of the technological performance of specific strains is better suited to selecting autochthonous starter cultures for fermented-meat products than in vitro evaluation.

Traditional dry fermented sausages produced in small-scale processing units in Mediterranean countries and Slovakia. 1: Microbial ecosystems of processing environments

Microbial ecosystems were surveyed in 314 environmental samples from 54 Southern and Eastern European small-scale processing units (PUs) manufacturing traditional dry fermented sausages. The residual microflora contaminating the surfaces and the equipment were analysed after cleaning and disinfection procedures. All the PU environments were colonised at various levels by spoilage and technological microflora with excessive contamination levels in some of the PUs. Sporadic contamination by pathogenic microflora was recorded. Salmonella and Listeria monocytogenes were detected in 4.8% and 6.7% of the samples, respectively, and Staphylococcus aureus was enumerated in 6.1% of the samples. Several critical points were identified, such as the machines for S. aureus and the tables and the knives for L. monocytogenes; this knowledge is crucial for the improvement of hygiene control systems in small and traditional meat processing industries. The variability of the residual contamination emphasized the different cleaning, disinfecting and manufacturing practices routinely followed by these small-scale processing units.

Microbiological characteristics of Botillo, a Spanish traditional pork sausage

Counts of total aerobic mesophilic flora on Standard Plate Count (SPC) agar, lactic acid bacteria on de Man Rogosa Sharpe (MRS) agar, salt tolerant flora on SPC agar +7.5% NaCl, and Enterobacteriaceae on Violet Red Bile Glucose (VRBG) agar, and some physico-chemical parameters (Total solids and NaCl contents and pH and a w values) were determined in 15 units of Botillo, a traditional dry-fermented sausage made in the NW of Spain. In general, high counts of all the investigated microbial groups were observed, with average values of 8.65 log Colony Forming Units (CFU)/g for the total aerobic mesophilic flora, 8.87 log CFU/g for the lactic acid bacteria, 6.56 log CFU/g for the salt tolerant flora, and 2.98 log CFU/g for the Enterobacteriaceae. After the end of the incubation period, from MRS agar, SPC agar +7.5% NaCl, and VRBG agar, 10 colonies were randomly taken from each Botillo unit and from each culture medium. A total of 150 strains per culture medium were then identified using classical methods. Among the isolates from MRS agar, Lactobacillus sakei predominated (23.3% of the isolates), followed by Lactobacillus alimentarius (17.3%), Lactobacillus curvatus (15.3%), Lactobacillus plantarum (12%) and Lactobacillus farciminis (10%). Of the 150 isolates obtained from SPC agar +7.5% NaCl, only 34 strains (22.6% of the isolates) belonged to the Staphylococcaceae or Micrococcaceae families. Among the Staphylococcaceae, Staphylococcus saprophyticus (8.6% of the isolates) was the main species, followed by Staphylococcus xylosus (4%), Staphylococcus lentus (2%) and Staphylococcus cohnii cohnii (1.3%); Staphylococcus epidermidis, Staphylococcus sciuri and Staphylococcus capitis were isolated in very low proportions. The Micrococcaceae strains isolated, belonging to the Micrococcus genus, could not be identified at species level. Of the 140 isolates obtained from VRBG agar, Hafnia alvei (32.14% of the isolates) was the main species, followed by Serratia liquefaciens (12.85%), Klebsiella oxytoca (5.71%) and Enterobacter cloacae (3.71%); only one isolate was identified as Salmonella ( Salmonella arizonae) and one as Escherichia coli.

Prevalence of biogenic amines during ripening of a traditional dry fermented pork sausage and its relation to the amount of sodium chloride added

The presence of biogenic amines (BA) along the processing stages and storage period of “Painho de Portalegre” and its relationship with the NaCl concentration on their levels were evaluated. Total BA concentration of current “Painho de Portalegre” dry fermented sausage increased ( P < 0.001) with drying/smoking processing time, attaining 655 mg kg −1 dry matter (DM) at day 6, a level about six times higher than that obtained in seasoned raw material mixtures before casing stuffing (115 mg kg −1 DM). Between day 30 and 40 in the drying/smoking house, that amount increased 20-fold (2500 mg kg −1 DM) over the initial concentration. After one month of storage under vacuum at room temperature, the concentration decreased by almost half to 1561 mg kg −1 DM. Excluding tyramine, the other BA were already present in the minced raw materials. However the sum of cadaverine, putrescine, histamine and tyramine, was well below 5 mg kg −1 proposed as BA limit for meat of high hygienic quality. Cadaverine was the most concentrated BA at the last stage of the drying/smoking (1430–1254 mg kg −1 DM, after 30 and 40 days, respectively), almost double the concentration of putrescine (882–779 mg kg −1 DM), followed by tyramine, β-phenylethylamine and spermine (376–311, 24 and 27–23 mg kg −1 DM, respectively). Variation was detected among production batches, possibly due to poor control of the processing conditions in traditional manufactures and the effects of the prevailing weather conditions. A higher salt concentration in the final product, 6% compared to 3%, led to a significant reduction in the BA level ( P < 0.001). This difference was particularly relevant in the early stage of the drying/smoking phase, during which the greatest microbial development mainly occurred in relation to cadaverine, β-phenylethylamine, putrescine and tyramine levels.

Microbiological characteristics of “androlla”, a Spanish traditional pork sausage

Counts of total aerobic mesophilic microflora, lactic acid bacteria, salt-tolerant microflora, Enterobacteriaceae, enterococci, moulds and yeasts, and staphylococci, and some physico-chemical parameters (total solids, NaCl and nitrate contents and pH and a w values) were determined in 20 units of “androlla”, a traditional dry-fermented sausage made in the NW of Spain. In general, high counts of all the investigated microbial groups were observed, with average values of 8.99±0.46 log cfu/g for the total aerobic mesophilic microflora, 9.11±0.16 log cfu/g for the lactic acid bacteria, 6.87±0.68 log cfu/g for the salt-tolerant microflora, 2.80±1.85 log cfu/g for the Enterobacteriaceae, 3.25±1.86 log cfu/g for the enterococci, 4.30±1.73 log cfu/g for the moulds and yeasts, and 3.62±0.60 log cfu/g for the staphylococci. From MRS agar, SPC agar+7.5% NaCl, VRBG agar, and KAA agar, 10 colonies were randomly taken from each androlla unit and from each culture medium. A total of 200 strains per culture medium were then identified using the classical methods. Among the isolates from MRS agar, Lactobacillus sakei predominated, followed by Lactobacillus curvatus, Lactobacillus alimentarius and Lactobacillus plantarum. Of the 200 isolates obtained from SPC agar+7.5% NaCl, only 56 strains belonged to the Staphylococcaceae or Micrococcaceae families. Among the Staphylococcaceae, Staphylococcus xylosus was the main species, followed by Staph. epidermidis; Staph. equorum, Staph. capitis and Staph. saprophyticus were isolated in very low proportions. Among the Micrococcaceae, Micrococcus luteus predominated, followed by Micrococcus lylae, Kocuria varians and Kocuria kristinae. Of the 150 isolates obtained from VRBG agar, Hafnia alvei was the main species, followed by Serratia liquefaciens and Enterobacter amnigenus; six isolates were identified as Salmonella. Among the 190 isolates obtained from KAA agar, 122 were considered enterococci; 20 isolates were identified as Enterococcus faecium, one as Enterococcus faecalis and 101 as Enterococcus inter faecalis-faecium.

Staphylococcal community of a small unit manufacturing traditional dry fermented sausages

The level and the diversity of the staphylococcal community occurring in the environment and meat products of a small unit manufacturing traditional dry fermented sausages were investigated at two seasons: winter and spring. Gram-positive cocci were enumerated and a collection of 412 Staphylococcus isolates was made. Multiplex PCR, pulse-field gel electrophoresis (PFGE) and sequencing of the sodA gene were used to identify and characterize the isolates. High counts of Staphylococcus were found in final traditional sausages, reaching about 6 log CFU/g in winter and about 8 log CFU/g in spring. In the environment, the counts varied from 2 log to 7 log/100 cm 2, the higher colonisation being observed on the surface of the drying and cold rooms, cutting tables and the butcher's block. The combination of the three methods allowed the identification of seven species of Staphylococcus in spring and five in winter. S. equorum and S. succinus dominated both in environment and in meat products, 49% and 33% of the isolates, respectively. The other identified species were in decreasing order S. saprophyticus (6%), S. xylosus (5%), S. carnosus (5%), S. simulans (1%) and S. warneri (1%). The two species S. xylosus and S. carnosus were sporadically isolated during the spring. PFGE allowed the assignment of S. equorum to eight pulsotypes showing a wide diversity among this species. But the entire environment and the meat products were dominated by one pulsotype. For S. succinus, three pulsotypes were found with one dominant mainly isolated during the spring sampling. This study highlighted the diversity of staphylococci isolated in the environment and the meat products of a small processing unit manufacturing traditional dry fermented sausages. The S. equorum and S. succinus species rarely described in meat products and never in the environment had great capacity to colonise the entire small processing unit and the meat products.

Perfiles de ácidos grasos totales y libres en embutidos crudo-curados tradicionales de Galicia

The total and free fatty acid contents were studied in ready for consumption samples of four different varieties of traditional dry-fermented sausages made in Galicia (NW of Spain): Chorizo gallego, Chorizo de cebolla, Androlla and Botillo. No significant differences (p>0.05) were observed in the content of the different total fatty acids among the four sausage varieties. The total fatty acids profile was very similar in the four varieties: the most abundant total fatty acid was oleic (45% of total fatty acids), followed by palmitic (21%), linoleic (14%), estearic (13%) and palmitoleic (2%); this profile basically coincides with those described by other authors in pork fat. The total average content of free fatty acids was 2176 mg/100 g of fat in Chorizo gallego, 5223 mg/100 g of fat in Chorizo de cebolla, 2308 mg/100 g of fat in Androlla and 183 mg/100 g of fat in Botillo. These average values in Chorizo gallego, Chorizo de cebolla and Androlla were found in the range of values described for other dry-fermented sausage varieties; the average value in Botillo was clearly lower than those decribed for other fermented sausages. In the four sausage varieties the most abundant free fatty acid was oleic, followed by linoleic, palmitic and estearic. This free fatty acid profile coincides with those described in literature for other dry-fermented sausages. The average content of each individual free fatty acid was significantly (p 0.05) were observed in the individual free fatty acid content between Chorizo gallego and Androlla. Using discriminant analysis 100% of the samples of Chorizo de cebolla and Botillo were correctly classified and differentiated from their content in individual free fatty acids. However, only 50% of samples of Chorizo gallego and 25% of samples of Androlla were correctly classified.

Effects of Indigenous Starter Cultures on the Microbial and Physicochemical Characteristics of Urutan, a Balinese Fermented Sausage

Urutan is a Balinese traditional dry fermented sausage prepared from lean pork and various kinds of spice. Urutan is different from the European sausages, because it is fermented under warm condition with fluctuating temperatures of approximately 25°C at night to 50°C during sun drying. In this study, two of the 71 strains of lactic acid bacteria (LAB) isolated from natural urutan fermentation were used as starter cultures: Lactobacillus plantarum U201, the dominant LAB, and Pediococcus acidilactici U318, a bacteriocin producer. A soft urutan with yellowish brown color was produced using these strains as multiple starters. The starter cultures grew in characteristic succession which reconstructed the natural fermentation process. Lactobacilli were dominant until 48 h fermentation and pediococci dominated at the later stage of fermentation. Proliferation of starter cultures produced lactic acid which resulted in the decrease in pH and coagulation of soluble protein in urutan . Both strains could eliminate the Enterobacteriaceae in urutan after 24 h fermentation, and could suppress and eliminate the occurrence of micrococci at 120 h fermentation. By using a single starter culture, no succession was observed to occur in urutan and the time of elimination of Enterobacteriaceae was delayed. Thus, the strains of L. plantarum U201 and P. acidilactici U318 have great potential for use as multiple starter cultures in urutan fermentation.

Effects of indigenous starter cultures on the microbial and physicochemical characteristics of Urutan, a balinese fermented sausage

Urutan is a Balinese traditional dry fermented sausage prepared from lean pork and various kinds of spice. Urutan is different from the European sausages, because it is fermented under warm condition with fluctuating temperatures of approximately 25°C at night to 50°C during sun drying. In this study, two of the 71 strains of lactic acid bacteria (LAB) isolated from natural urutan fermentation were used as starter cultures: Lactobacillus plantarum U201, the dominant LAB, and Pediococcus acidilactici U318, a bacteriocin producer. A soft urutan with yellowish brown color was produced using these strains as multiple starters. The starter cultures grew in characteristic succession which reconstructed the natural fermentation process. Lactobacilli were dominant until 48 h fermentation and pediococci dominated at the later stage of fermentation. Proliferation of starter cultures produced lactic acid which resulted in the decrease in pH and coagulation of soluble protein in urutan. Both strains could eliminate the Enterobacteriaceae in urutan after 24 h fermentation, and could suppress and eliminate the occurrence of micrococci at 120 h fermentation. By using a single starter culture, no succession was observed to occur in urutan and the time of elimination of Enterobacteriaceae was delayed. Thus, the strains of L. plantarum U201 and P. acidilactici U318 have great potential for use as multiple starter cultures in urutan fermentation.

Evidence for proteolytic activity and biogenic amines production in Lactobacillus curvatus and L. homohiochii

After screening 372 strains of Lactobacillus spp. isolated from a Portuguese traditional dry fermented sausage, two Lactobacillus strains, a Lactobacillus homohiochii and a L. curvatus were selected, because they were positive for tyrosine and ornithine decarboxylase activities. Evidence for extracellular proteolytic activity was also demonstrated for the two Lactobacillus strains, with some strain variation in terms of specific activities towards different substrates. Proteolytic activity was shown to be maximal in the early exponential growth. This proteolytic activity was higher when cells were grown in a peptide-rich medium such as MRS, when compared to skim milk. A study using several protease inhibitors showed that this activity is associated with metalloproteases in the case of the L. curvatus strain, but for L. homohiochii besides metalloproteases, serine-type proteases are also involved. In proteinaceous substrates, like dry fermented sausages, the formation of the biogenic amines putrescine and tyramine cannot be excluded when ongoing proteolysis leads to their precursors, as it is the case in the presence of these proteolytic Lactobacillus strains. Their ability to produce biogenic amines may be used as an index of microbial quality of the fermented meat product.

Effect of the Addition of a Neutral Proteinase from Bacillus subtilis (Neutrase) on Nitrogen Fractions and Texture of Spanish Fermented Sausage

The effect of a metalloproteinase from Bacillus subtilis (Neutrase from Novo Nordisk) on the evolution of some nitrogen fractions during the ripening of a traditional dry fermented sausage (chorizo) was studied. The use of Neutrase especially affected myofibrillar proteins, giving rise to a higher loss of solubility than that produced in the sarcoplasmic proteins. The lowest soluble myofibrillar nitrogen of the products with Neutrase did not decrease the water-holding capacity. Sausages with Neutrase showed an increase in the nonprotein nitrogen fraction higher than that for sausages without enzyme. The increases in free α-NH2 nitrogen during the ripening were very similar for both types of sausage. In the peptide fraction the α-NH2 nitrogen increase was much higher in the product with Neutrase (78.29%) than in the product without enzyme (20.93%). Sensory analysis showed some slight differences in the texture parameters which were not correlated to product acceptability. Keywords: Fermented sausages; exog...