Starter Formulation Research Articles

Description of “Ovino Belmontese”, a new semisoft sheep's milk cheese processed using “Italico” cheese technology

The objective of this study was to create a new semisoft sheep's milk cheese called “Ovino Belmontese” cheese (OBCh) by applying the “Italico” cheese-making technology. The cheese production took place under industrial conditions, with the addition of a commercial starter formulation containing Streptococcus thermophilus. The microbiological, physicochemical, and sensory characteristics of OBCh were assessed and compared to those of a commercially available cow's Italico cheese (CICh). Streptococcus thermophilus dominated the microbial community during the cheese-making process, reaching levels of approximately 9.0 Log CFU/g in both OBCh and CICh. Among physical characteristics, no statistically significant difference (p ≥ 0.05) was registered in terms of lightness, redness, yellowness, and hardness between the two cheeses. OBCh exhibited a twofold higher short-chain fatty acid content compared to CICh. Both cheeses displayed similar classes of volatile organic compounds, although their relative percentages differed. The application of Italico cheese technology to process sheep's milk did not negatively affect sensory attributes. This study highlighted that utilizing a cheese-making technology not commonly used for processing sheep's milk represents a promising strategy to diversify Sicilian dairy productions.

A mixture design approach to develop new starter formulation for Lben: Key aroma compounds, physical, chemical and sensory properties of the product

The study investigated the evolution of the physicochemical and sensory properties of Lben fermented milk inoculated with different starter formulations. The aim was to determine the optimal starter culture formula for Lben production using different combinations of four strains, including three strains of Lactococcus lactis subsp. lactis with strain codes A, E and F and one strain of Leuconostoc mesenteroides subsp. mesenteroides with strain code C. While individual strains had previously demonstrated significant technological and organoleptic properties their interaction in mixtures had not been explored. In the study, a response surface methodology (mixture design approach) was applied to evaluate the effects of the interactions between strains on the physicochemical, antioxidant, volatile, and sensory properties of Lben, a fermented milk. In addition, product optimization using ridge analysis was performed to determine the ideal strain mixture formulation based on the sensory properties of Lben. The optimization goal for odor, taste, consistency, and overall preference was set to maximize their values. A high desirability score of 0.832 was achieved with the following percentage distribution: 34.39% for L. lactis E, 42.38% for L. lactis A, 10% for L. lactis F, and 13.23% for Leuc. mesenteroides C.

Development of "Quadrello di Ovino", a Novel Fresh Ewe's Cheese.

This work was performed to produce a new soft ewe’s milk cheese, namely “Quadrello di ovino” (QdO) cheese, to enlarge ewe’s dairy product portfolio of South Italy, barely limited to Pecorino cheese typology. Cheese making was performed applying the technology for “Crescenza” cheese typology with some modifications. In particular, pasteurized ewes’ milk was inoculated with two commercial starter formulations (SF1 and SF2) of Streptococcus thermophilus to obtain two different productions (QdO-P1 and QdO-P2, respectively). Plate counts demonstrated the ability of both starter formulations to drive the fermentation process, since S. thermophilus counts reached 109 CFU/g in both productions. Generally, the two starter formulations did not affect the chemical composition of QdO cheeses that contained, on average, 64.08% dry matter of which approximately 54.99% were fats and 36.39% proteins. Among chemical parameters, significant differences were registered for secondary lipid oxidation state (significantly lower for QdO-P2), fatty acids and volatile organic compounds (VOCs). However, the differences registered among cheese VOCs from were not perceived by the panelists who recognized both cheese productions highly similar, although QdO-P2 cheeses were mostly appreciated by the judges. This study allowed to produce a novel fresh ovine cheese with specific chemical and sensorial characteristics well appreciated by consumers.

비타민나무 잎 배합비율에 따른 사워도우 첨가 모닝빵의 품질 특성 및 항산화 활성

In this study, a natural fermentation starter formulation was developed for functional bread products by substituting baker’s yeast with naturally fermented sourdough added with sea buckthorn leaf (SBL). The quality and antioxidant properties of morning bread (MB) with 0%, 10%, 20%, and 30% SBL added to sourdough were investigated. The pH of MB dough decreased when the mixing ratio (MR) of SBL was increased. The dough-raising power by incubation time (20-60 min) increased when the MR of SBL was increased. In the MB containing 30% SBL sourdough, the height was lowest, and the baking loss rate was highest. The specific volume of the control was the highest. The L value decreased, whereas the b values increased, when MR of SBL was increased. Hardness was the highest in MB containing 20% SBL sourdough. Total polyphenolic and total flavonoid contents tended to increase as SBL increased. DPPH and ABTS+ radical scavenging activities and reducing power of MB were also elevated due to addition of MR of SBL. The sensory evaluation results revealed that MB containing 20% SBL sourdough the highest overall preference. Collectively, these results indicated that sourdough with 20% SBL was a very useful substitute for baker’s yeast when making naturally fermented functional bread.

Design of an autochthonous starter culture using strains isolated from traditional Matsoni.

Artisanal products support the conservation of the indigenous biodiversity of food microbiomes, although they do not always comply to quality and hygienic requirements for the dairy industry. This study describes the development of an autochthonous starter culture to produce Matsoni, a traditional Georgian fermented milk. To this end, strains of lactic acid bacteria isolated from artisanal Matsoni samples were used to design a starter formulation reproducing the dominant microbial diversity, also preserving quality characteristics and ensuring the safety of the product. As a result, strains that represent the acidifying portion of the starter (Lactobacillus delbrueckii subsp. lactis, L. delbrueckii subsp. bulgaricus and Streptococcus thermophilus) were combined in different ratios and strain combinations, together with cultures of Lactobacillus rhamnosus that were chosen for their potential beneficial traits. The strain association acting better in milk cultures at laboratory scale was selected as starter culture for the production of Matsoni in pilot-scale industrial trials.

Evaluation and Application of Different Cholesterol-Lowering Lactic Acid Bacteria as Potential Meat Starters

A total of 115 isolates of lactic acid bacteria were screened from traditional fermented foods in Guizhou Province, People's Republic of China. The cholesterol removal rates of 86 isolates ranged from 7.29 to 25.66%, and 18 isolates showed a cholesterol removal rate of more than 15%. According to the results of physiological and biological tests, 13 isolates were selected to determine the fermentation performance; 9 isolates-MT-4, MT-2, PJ-15, SR2-2, SQ-4, SQ-7, ST2-2, ST2-6, and NR1-7-had high tolerance of bile salt and acid and had a survival rate of more than 96% under pH 3.0 and 0.3% bile salt. ST2-2, SR2-2, NR1-7, SQ-4, and MT-4 had high survival rate in different concentrations of NaCl and NaNO2 under different temperatures. According to BLAST comparison results of the 16S rRNA sequence in the GenBank database and the genetic distance of the 16S rRNA sequence with an ortho-connected algorithm, SR2-2, NR1-7, and ST2-2 were identified as Lactobacillus plantarum, MT-4 was identified as Lactobacillus pentosus, and SQ-4 was identified as Lactobacillus paraplantarum. Moreover, strains SQ-4 and MT-4 were added to fermented beef. Results showed that the fermented beef had delicious taste and was popular to consumers because of its proper pH, pleasant colors, high viable cell count, and suitable content of bound and immobilized water. These results provide a basis for the development of new starter formulation for the production of high-quality fermented meat products.

Effect of Co-Inoculation of Candida zemplinina, Saccharomyces cerevisiae and Lactobacillus plantarum for the Industrial Production of Negroamaro Wine in Apulia (Southern Italy).

The employment of multi-species starter cultures has growing importance in modern winemaking for improving the complexity and wine attributes. The assessment of compatibility for selected species/strains at the industrial-scale is crucial to assure the quality and the safety associated with fermentations. An aspect particularly relevant when the species belong to non-Saccharomyces, Saccharomyces spp. and malolactic bacteria, three categories with different biological characteristics and oenological significance. To the best of our knowledge, the present report is the first study regarding the utilization of a combined starter culture composed of three strains of non-Saccharomyces, Saccharomyces cerevisiae and Lactobacillus plantarum for production of wine at the industrial scale. More in-depth, this work investigated the oenological potential of the autochthonous characterized strains from the Apulian region (Southern Italy), Candida zemplinina (syn. Starmerella bacillaris) 35NC1, S. cerevisiae (NP103), and L. plantarum (LP44), in co-inoculation following a complete scale-up scheme. Microbial dynamics, fermentative profiles and production of volatile secondary compounds were assessed in lab-scale micro-vinification tests and then the performances of the mixed starter formulation were further evaluated by pilot-scale wine production. The above results were finally validated by performing an industrial-scale vinification on 100HL of Negroamaro cultivar grape must. The multi-starter formulation was able to rule the different stages of the fermentation processes effectively, and the different microbial combinations enhanced the organoleptic wine features to different extents. The findings indicated that the simultaneous inoculation of the three species affect the quality and quantity of several volatile compounds, confirming that the complexity of the wine can reflect the complexity of the starter cultures. Moreover, the results underlined that the same mixed culture could differently influence wine quality when tested at the lab-, pilot- and industrial-scale. Finally, we highlighted the significance of employment non-Saccharomyces and L. plantarum, together with S. cerevisiae, autochthonous strains in the design of custom-made starter culture formulation for typical regional wine production with pronounced unique quality.

Bacterial diversity of naturally fermented game meat sausages: Sources of new starter cultures

Bacterial communities associated with the ripening process in artisanal wild boar and deer meat sausages were investigated by molecular barcoding using the 16S rRNA gene as a marker. A core microbiota shared by 83.54% of the samples indicated remarkable level of Lactobacillus sakei and Lactobacillus curvatus, accounting for 20.55% in initial and 70.48% in final products as well as spoilage-associated bacteria including Stenotrophomonas, Bacillus, Pseudomonas, Carnobacterium and Brochothrix, with an average abundance 44.15% at the beginning and 13.98% at the end of the production. Of selected LAB isolates (n = 555), 43.83% were not suitable for food application due to the antibiotic resistance or the presence of the tdc gene. Most of the strains designated as safe were able to grow at 25 °C even in the presence of 3.0 and 6.0% of NaCl or pH 4.5, but exposure to the same stressors resulted in growth reduction at 12 °C. Acidification and antimicrobial activity were found in 65.62% and 37.50% of strains, respectively. Most of the strains showed lipolytic and proteolytic activity, but only 9.37% were able to degrade sarcoplasmic proteins. These results give important information for the development of new starter formulation for the production of high quality game meat sausages.

Exploitation of Prunus mahaleb fruit by fermentation with selected strains of Lactobacillus plantarum and Saccharomyces cerevisiae

The organoleptic attributes of Prunus mahaleb, a fruit representing a new source of bioactive compounds, are so pronounced that it can be consider non-edible. This study was designed to evaluate the acceptance of P. mahaleb fruits after fermentation with different Saccharomyces cerevisiae and Lactobacillus plantarum protechnological strains. Four different bacterial and one yeast strains, as single or mixed starter formulation, were used to inoculate an aqueous suspension of P. mahaleb fruits. The fermented fruits and fermentation broths were subjected to physico-chemical characterization and the organoleptic properties of both samples were also assessed by a hedonic panel. The obtained results indicated that all the employed strains were able to grow and to ferment the matrix. However, the mixed starter FG69 + Li180-7 (L. plantarum/S. cerevisiae) had the best impact on sensory characteristics of P. mahaleb fruit and fermented medium. The adopted protocol allowed us to attain edible fruits and a new fermented non-dairy drink with valuable probiotic health-promoting properties. In our knowledge, this is the first study concerning the exploitation of P. mahaleb fruits. This investigation confirmed the potential of yeasts and lactic acid bacteria co-inoculation in the design of starter tailored for this kind of food applications.

Impact of co-inoculation of Saccharomyces cerevisiae, Hanseniaspora uvarum and Oenococcus oeni autochthonous strains in controlled multi starter grape must fermentations

The use of multi-species starter cultures is an approach of increasing significance for winemakers in order to improve the general quality and safety of the final product. As first step of the present study, we isolated and characterize two Saccharomyces cerevisiae yeast starter strains, denoted as ITEM 167292 and ITEM 17293, from natural must fermentations of “Negroamaro” grapes. As second step, we studied the interactions during grape must fermentation between these two strains, the Hanseniaspora uvarum strain ITEM 8785 and five autochthonous Oenococcus oeni strains, by microbial counts and by quantifying l-malic acid and ethanol concentrations. The best performing O. oeni strain, namely OT4, was used to create, with the H. uvarum strain ITEM 8785, two mixed starter formulations with the strains ITEM 167292 and ITEM 17293. The three microbial species showed to be compatible and to complete the fermentative processes producing wines denoted by reduced acetic acid concentrations. The performance of the mixed starter formulations were then validated by carrying pilot-scale vinifications. At the best of our knowledge, this report is the first study regarding the utilization of selected H. uvarum/S. cerevisiae/O. oeni autochthonous strains in a simultaneous multi-starter inoculation for the industrial production of regional typical wines.

Corrigendum to: Porcine bile powder supplementation of a high fat broiler diet in relation to growth performance and nutrient digestion

The aim of the study was to examine the effect of pig bile powder supplementation on the digestibility of nutrients, fat digestion and growth performance of starter broilers fed on a high fat diet. A total of 1110, day-old, male broiler chicks (Arbor Acres) were randomly allocated into six treatment groups with five replicates per treatment. The chicks were fed on a corn-soybean meal basal diet with a starter formulation until Day 14, followed by a grower formulation until Day 21. In group 1 (T1), the basal diet contained 30 g/kg crude palm oil whereas the diet used in group 2 (T2) had 60 g/kg crude palm oil. Chicks in group 3 (T3) were fed on T2 diet supplemented with 5.0 g/kg soy lecithin as the positive control. Chicks in groups 4–6 (T4–T6) received diets used in T2, supplemented with 1.25, 2.5 and 5.0 g/kg lyophilised pig bile powder, respectively. On Days 4, 7, 14 and 21, chicks were killed, portal blood was collected and analysed for fatty acids, pancreas collected for measurement of pancreatic lipase activity, bile and jejunal contents for bile acid determination and ileal content for determining digestibility of fat and protein. The results showed (1) there was no difference in bodyweight and feed intake among T2–T6, (2) pancreatic lipase activity of chicks in T4 and T5 was highest in all periods. Total bile acid concentrations in the gall bladder and jejunum in T4 was lower than those in T2 in all periods, and Days 4 and 7, respectively, (3) digestibility of protein and fat in T3 and T4 was higher in all the period than that of T2, T5 and T6, (4) increased fat content in the diet did not cause a significant increase in any fatty acids in the portal plasma when compared T1 and T2. In conclusion, 2.5 g/kg porcine bile powder supplemented in high fat diet increased pancreatic lipase activity and total bile acid concentrations in gall bladder, resulting in increased ileal digestibility of fat and protein.

Porcine bile powder supplementation of a high fat broiler diet in relation to growth performance and nutrient digestion

The aim of the study was to examine the effect of pig bile powder supplementation on the digestibility of nutrients, fat digestion and growth performance of starter broilers fed on a high fat diet. A total of 1110, day-old, male broiler chicks (Arbor Acres) were randomly allocated into six treatment groups with five replicates per treatment. The chicks were fed on a corn-soybean meal basal diet with a starter formulation until Day 14, followed by a grower formulation until Day 21. In group 1 (T1), the basal diet contained 30 g/kg crude palm oil whereas the diet used in group 2 (T2) had 60 g/kg crude palm oil. Chicks in group 3 (T3) were fed on T2 diet supplemented with 5.0 g/kg soy lecithin as the positive control. Chicks in groups 4–6 (T4–T6) received diets used in T2, supplemented with 1.25, 2.5 and 5.0 g/kg lyophilised pig bile powder, respectively. On Days 4, 7, 14 and 21, chicks were killed, portal blood was collected and analysed for fatty acids, pancreas collected for measurement of pancreatic lipase activity, bile and jejunal contents for bile acid determination and ileal content for determining digestibility of fat and protein. The results showed (1) there was no difference in bodyweight and feed intake among T2–T6, (2) pancreatic lipase activity of chicks in T4 and T5 was highest in all periods. Total bile acid concentrations in the gall bladder and jejunum in T4 was lower than those in T2 in all periods, and Days 4 and 7, respectively, (3) digestibility of protein and fat in T3 and T4 was higher in all the period than that of T2, T5 and T6, (4) increased fat content in the diet did not cause a significant increase in any fatty acids in the portal plasma when compared T1 and T2. In conclusion, 2.5 g/kg porcine bile powder supplemented in high fat diet increased pancreatic lipase activity and total bile acid concentrations in gall bladder, resulting in increased ileal digestibility of fat and protein.

Penicillium species: crossroad between quality and safety of cured meat production

Fermented meat products, praised for their culinary heritage and identity, represent crossroads of innovation and tradition, quality and healthiness. Mold growth of some Penicillium species is highly desired in some dry-cured meat products, due to their contribution to flavour, anti-oxidative effects and protective role against detrimental microorganisms. Penicillium salamii has been recently described as a promising candidate for starter formulations for meat industry. Otherwise, undesirable species, like Penicillium nordicum, could colonize and contaminate cured meat with ochratoxin A or other related mycotoxins. To this aim, LAMP and other DNA-based assays represent useful tools for early detection of toxigenic fungi and therefore for effective mycotoxins risk managing.

Microbial ecology involved in the ripening of naturally fermented llama meat sausages. A focus on lactobacilli diversity

Llama represents for the Andean regions a valid alternative to bovine and pork meat and thanks to the high proteins and low fat content; it can constitute a good product for the novel food market. In this study, culture-dependent and independent methods were applied to investigate the microbial ecology of naturally fermented llama sausages produced in Northwest Argentina. Two different production technologies of llama sausage were investigated: a pilot-plant scale (P) and an artisanal one (A). Results obtained by High-Throughput Sequencing (HTS) of 16S rRNA amplicons showed that the production technologies influenced the development of microbial communities with a different composition throughout the entire fermentation process. Both sequencing and microbiological counts demonstrated that Lactic Acid Bacteria (LAB) contributed largely to the dominant microbiota. When a total of 230 isolates were approached by RAPD-PCR, presumptive LAB strains from P production exhibited an initial variability in RAPD fingerprints switching to a single profile at the final of ripening, while A production revealed a more heterogeneous RAPD pattern during the whole fermentation process. The constant presence of Lactobacillus sakei along the fermentation in both productions was revealed by HTS and confirmed by species-specific PCR from isolated strains. The technological characterization of Lb. sakei isolates evidenced their ability to grow at 15°C, pH4.5 and 5% NaCl (95%). Most strains hydrolyzed myofibrillar and sarcoplasmic proteins. Bacteriocins encoding genes and antimicrobial resistance were found in 35% and 42.5% of the strains, respectively. An appropriate choice of a combination of autochthonous strains in a starter formulation is fundamental to improve and standardize llama sausages safety and quality.

Characterization of the Microbial Flora from Suan Yu, a Chinese Traditional Low-Salt Fermented Fish

The microbial flora of naturally fermented Suan yu was investigated by phenotype combined with gene analysis at different stages of fermentation. Results shows that lactic acid bacteria (LAB) and yeast were gradually increased during fermentation and the counts were ripening to 7.93–8.56 and 5.14–5.75 log cfu/g, respectively, at the end of the fermentation. Staphylococci gradually increased during the first fermentation stage and then slowly decreased until the end of ripening (4.13–4.92 log cfu/g). Majority of the LAB isolated from Suan yu were Lactobacillus plantarum and Pediococcus pentosaceus, followed by Leuconostoc and Lactobacillus paralimentarius species. The yeast mainly consisted of Saccharomyces cerevisiae and Hansenula anomala. The predominant Staphylococcus isolated from Suan yu comprised Staphylococcus saprophyticus and Staphylococcus xylosus. The main microorganism in early fermentation included Leuconostoc mesenteroides, Pseudomonas and Enterobacteriaceae and the followed subsequent stage included L. plantarum, P. pentosaceus, S. xylosus, S. saprophyticus, S. cerevisiae and H. anomala. Practical Applications In this study, the specific microorganisms and their microbial dynamics were investigated during Suan yu fermentation. Results showed that lactic acid bacteria, coagulase-negative Staphylococci and yeat were predominant microorganisms during the ripening fermentation. Therefore, these predominant organisms are responsible for the Suan yu unique flavor, taste, color and ensure their safety. Furthermore, selecting the most appropriate autochthonous microflora as starter formulation can effectively preserve the typical characteristics of the Suan yu.

Impact of yeast starter formulations on the production of volatile compounds during wine fermentation

The most diffused starter formulation in winemaking is actually represented by active dry yeast (ADY). Spray-drying has been reported as an appropriate preservation method for yeast and other micro-organisms. Despite the numerous advantages of this method, the high air temperatures used can negatively affect cell viability and the fermentative performance of dried cells. In the present study, 11 wine S. cerevisiae strains (both indigenous and commercial) were submitted to spray-drying; different process conditions were tested in order to select the conditions allowing the highest strain survival. The strains exhibited high variability for tolerance to spray-drying treatment. Selected strains were tested in fermentation at laboratory scale in different formulations (free fresh cells, free dried cells, immobilized fresh cells and immobilized dried cells), in order to assess the influence of starter formulation on fermentative fitness of strains and aromatic quality of wine. The analysis of volatile fraction in the experimental wines produced by selected strains in different formulations allowed identification of > 50 aromatic compounds (alcohols, esters, ketones, aldehydes and terpenes). The results obtained showed that the starter formulation significantly influenced the content of volatile compounds. In particular, the wines obtained by strains in dried forms (as both free and immobilized cells) contained higher numbers of volatile compounds than wines obtained from fresh cells.

Soybean Meal Retains Its Nutritional Value as an Animal Feed Following in Situ Transesterification

AbstractThe lipid‐depleted meal transesterified soybean meal (TSM) coproduct of the in situ transesterification of soybeans to produce biodiesel, and a reference commercial hexane‐extracted soybean meal (HSM), were investigated as poultry feeds. In situ transesterification removed 95 % of the lipid from soybean flakes without destroying amino acids or affecting caloric content. Trypsin inhibitor in TSM was successfully denatured by a steam/heat treatment. Two groups of broiler chicks, each consisting of 300 birds (20/pen), were fed diets whose soy meal component was either TSM or HSM. A block design was used, a ‘block’ consisting of two adjacent pens, one receiving TSM and the other HSM. Starter formulation was fed from day 1 to 21 and grower formulation from day 22 to the end of the study on day 42. Chicks accepted both the TSM and HSM diets. No acute toxicities occurred. Over the course of the study weight gain, feed consumption and feed efficiency were comparable (p ≥ 0.05) between the two test groups. Mortalities in the group receiving TSM exceeded those in the HSM group (6.8 vs. 3.4 %), but did not reach statistical significance. Histological examination of the livers of 40 birds sacrificed at the end of the study showed no evidence of pathology in either dietary group. Soybean meal subjected to in situ transesterification is an acceptable component of poultry diets.

Lactococcus lactis strains from raw ewe’s milk samples from the PDO Ossau-Iraty cheese area: levels, genotypic and technological diversity

The aims of this work were to assess the levels of Lactococcus lactis (L. lactis) in ewe’s milk produced in three Ossau-Iraty cheese sub-areas and to investigate the genotypic and technological diversity of isolated wild strains of L. lactis in order to assess their suitability for use as components of starter formulations. Thirty-two milk samples from 32 farms were collected. Strains of L. lactis were identified and quantified using a combination of species and subspecies-specific polymerase chain reaction (PCR) and PCR amplification of repetitive bacterial DNA elements (Rep-PCR). The genotypic and technological diversity of the indigenous strains was compared to that of 12 commercial strains. L. lactis was detected in milk samples from only 20 farms. The levels detected were below 4 log10 cfu.mL−1 in 75% of the milks. L. lactis subsp. lactis dominated in 66% of the samples. Forty-three genotypic profiles of wild L. lactis strains were detected and showed greater diversity than those of the commercial strains. Milks containing L. lactis contained one to four distinct strains. With the exception of two strains, each strain was found in milk from only one farm. The Prt+ strains were the most acidifying. Sensitivity to phages collected from wheys differed widely between the commercial (60%) and indigenous strains (5%). Wild strains of L. lactis displayed a wide genotypic and technological diversity. Genotypic diversity seemed to be linked to the farm of origin. This study addresses questions regarding the environmental factors which influence such natural diversity. A deeper knowledge of the strain-dependent technological properties would be useful in selecting strains for use in starter blends.

Proteolytic and lipolytic starter cultures and their effect on traditional fermented sausages ripening and sensory traits

In this study, three starter formulations including Lactobacillus curvatus and Staphylococcus xylosus strains selected in vitro on the basis of their lipolytic and proteolytic activities were employed for the manufacture of traditional fermented sausages of southern Italy. Microbial population, proteolysis, lipolysis, changes in free amino acids (FAA) and free fatty acids (FFA) and development of characteristic taste and flavor of the final product were investigated. Proteolysis and lipolysis were observed in sausages inoculated with proteolytic and lipolytic S. xylosus coupled with L. curvatus, while the sausage started with only S. xylosus without lactobacilli was identical to the non-inoculated control, indicating that the proteolysis could be due to both microbial activity and endogenous proteases activated by the decrease in pH. The statistical analysis applied to the instrumental and sensory data showed that there was an effect of the starter used on the characteristics of the sausage obtained. In particular, the control samples showed very close features different from the sausages obtained by adding starter cultures. Finally, analyzing the sensory parameters the sausages ripened without starter addition and those started without the L. curvatus AVL3 showed similar features indicating an influence of the presence of the lactobacilli on the final organoleptic quality of the sausages. An appropriate choice of a combination of strains in a starter formulation is fundamental to obtain products of the expected quality.

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.