Biochemical and sensory characteristics of traditional fermented sausages of Vallo di Diano (Southern Italy) as affected by the use of starter cultures

Changes in protein and volatile flavor compounds of low-salt wet-marinated fermented Golden Pomfret during processing

In this experiment, the changes in protein hydrolysis, protein oxidation, and flavor of low-salt wet-marinated fermented golden pomfret were studied during processing. During processing, a decrease in sulfhydryl content (P < 0.05), a significant increase in protein surface hydrophobicity (P < 0.05), a significant increase in carbonyl content and TCA-soluble peptide (P < 0.05), an increase in TVB-N and amino acid nitrogen (P < 0.05), and a significant increase in the content of free amino acids (P < 0.05), indicating that proteins were gradually oxidized and degraded to small molecules and flavor precursors under the action of bacterial reduction pretreatment, deodorization, marination and fermentation processes, small molecules and aroma precursors was generated by gradual oxidative decomposition. In the course of processing, a total of 113 volatile flavor compounds were identified using GC-MS analysis, while OPLS-DA analysis and VIP value determination led to the identification of 10 characteristic flavor compounds. The results showed that an abundance of flavor compounds was generated during the processing, thereby imparting a more pronounced taste profile to the low-salt wet-marinated fermented golden carp. The results showed that a large number of flavor substances were generated during the processing to give a richer flavor to low-salt wet-marinated fermented golden pomfret that could provide data and theoretical support for the subsequent processing industry of golden pomfret.

Inoculation fermentation with Lactobacillus fermentum L28 and Staphylococcus epidermidis S24 for improving the protein degradation of air-dried goose

The inoculation fermentation technology was applied to the processing of dried cured goose to investigate the protein degradation. Lactobacillus fermentum (L), Staphylococcus epidermidis (S) and mixed strains (L + S) were individually inoculated into the whole goose before drying. We studied the degradation of protein in the air-dried period of goose. The results showed that compared with natural fermentation, inoculation fermentation significantly increased the content of non-protein nitrogen (14.85 mg/g NPN), proteolysis index (8.98% PI), myofibril fragmentation index (89.35 MFI) and total amount of free amino acids (1332.6 mg/g FAA) of dried cured goose. Electrophoresis revealed that the inoculation fermentation accelerated the degradation of macromolecular proteins and the accumulation of small molecular proteins. The degree of protein degradation in four groups of goose was in an order of L + S group > S group > L group > CK group. It suggested that inoculation fermentation could promote the degradation of myofibrillar proteins.

Effects of Inoculating Autochthonous Starter Cultures on Changes of N-Nitrosamines and Their Precursors in Chinese Traditional Fermented Fish during In Vitro Human Digestion

The objective of this research was to investigate the impact of inoculating autochthonous starter cultures on the alterations in microorganisms, biogenic amines, nitrite, and N-nitrosamines in Chinese traditional fermented fish products (CTFPs) during in vitro human digestion. The results revealed that gastric digestion significantly (p < 0.05) inhibited the proliferation of lactic acid bacteria, yeast, Staphylococcus, and Enterobacteriaceae, whereas various microorganisms proliferated extensively during small intestine digestion. Meanwhile, small intestine digestion could significantly increase (p < 0.05) levels of putrescine, cadaverine, and tyramine. The reduced content observed in inoculated fermentation groups suggests that starter cultures may have the ability to deplete biogenic amines in this digestion stage. Gastric digestion significantly (p < 0.05) inhibited nitrite accumulation in all CTFPs samples. Conversely, the nitrite content increased significantly (p < 0.05) in all groups during subsequent small intestine digestion. However, the rise in the inoculated fermentation groups was smaller than that observed in the spontaneous fermentation group, indicating a potentially positive role of inoculated fermentation in inhibiting nitrite accumulation during this phase. Additionally, gastric digestion significantly (p < 0.05) elevated the levels of N-nitrosodimethylamine (NDMA) and N-nitrosopiperidine in CTFPs. Inoculation with L. plantarum 120, S. cerevisiae 2018, and mixed starter cultures (L. plantarum 120, S. cerevisiae 2018, and S. xylosus 135 [1:1:1]) effectively increased the degree of depletion of NDMA during this digestion process.

Effects of Fermentation Temperature, Drying Temperature, Caliber Size, Starter Culture, and Sodium Lactate on Listeria monocytogenes Inactivation During Salami Production

The effect of fermentation and drying temperatures, caliber, and sodium lactate on Listeria monocytogenes inactivation was studied in salami, produced in a pilot scale, inoculated with 107 CFU/g of Listeria innocua ATCC® 33090 as a surrogate microorganism for L. monocytogenes. Fermentation temperature varied between 24 and 30°C, drying temperature between 14 and 20°C, caliber between 5.1 and 13.2 cm, and sodium lactate initial concentrations in salamis were 0 and 2%. L. innocua counts, pH and water activity were determined in salamis over time. Sodium lactate (2%) decreased pH drop and Listeria inactivation during fermentation. Baranyi & Roberts equation was used to fit the experimental data and to estimate, for each test condition, inactivation rate (k), initial (Y0), and final counts of L. innocua (YEND). Total inactivation was calculated as Y0 minus YEND (Y0-YEND). Then, using a Box Benkhen experimental design, a quadratic model for k and a two-factor interaction model (2FI) for Y0 - YEND were obtained as functions of fermentation temperature, drying temperature, and caliber size. The models predicted that maximum k and Y0 -YEND, -2.62 ± 0.14 log10 CFU/g/day and 4.5 ± 0.1 log10 CFU/g, respectively, would be obtained fermenting at 30°C and drying at 20°C regardless of caliber. Drying at 14°C allowed Listeria growth until a water activity (aw) of 0.92 was reached. Therefore, if initial Listeria contamination is high (3 log10 CFU/g), drying at low temperatures will compromise product safety.

Comparative study of a liposome and emulsion system with cinnamon essential oil on the quality and proteolysis of refrigerated minced pork

Essential oils have been recognized for their strong antibacterial property, making them an innovative approach for preserving meat. However, their chemical instability and direct impact on meat proteins limit their application. To overcome these limitations, various loading systems have been explored. This study aimed to compare the effect of cinnamon essential oil (CEO) loaded in a liposome and emulsion system on the proteolysis of minced pork and to evaluate the advantages of each delivery system in preventing microorganism-induced quality deterioration of meat. Minced pork treated with CEO-liposomes exhibited lower pH, total volatile basic nitrogen (TVB-N), and total viable count (TVC) values than CEO-emulsions and provided better protection against microorganisms. SDS-polyacrylamide gel electrophoresis (PAGE) analysis confirmed that CEO-liposome was more effective in protecting proteins from degradation. Moreover, CEO-liposome produced lower amount of bitter amino acids and harmful biogenic amines. Antibacterial mechanisms indicated that CEO-liposome exhibited a stronger inhibitory effect against major spoilage bacteria in meat products by increasing cell membrane permeability. The membrane damage was further supported by an increase in conductivity and the leakage of nucleic acids. Compared to the CEO-emulsion system, CEO-liposome emerged as an effective preservative for minced pork. These results provided important theoretical support for using a bioactive compound delivery system to prevent microorganism-induced quality deterioration in meat.

Two Debaryomyces hansenii strains as starter cultures for improving the nutritional and sensory quality of dry-cured pork belly

Dry-cured meat products are gaining attention owing to their distinctive sensory characteristics and health benefits. In this study, two Debaryomyces hansenii strains were investigated for their potential as starter cultures for dry-cured pork belly products. After preliminary screening, these D. hansenii strains, namely, S20 and S26, both exhibiting with excellent aroma-producing capacity in a dry-cured meat model, were selected as single-strain starter cultures. For comparison, a non-inoculated control was also evaluated. In S20- and S26-inoculated pork belly, yeast dominated the microbiota and improved microbiological safety by suppressing Enterobacteriaceae growth. Compared with the non-inoculated control, the inoculated pork belly yielded higher hardness and redness (a*) values. Starter culture inoculation accelerated proteolysis in pork belly, improving the content of total free amino acids (TFFAs) and several essential free amino acids (Thr, Val, Met, Ile, Leu, and Phe) at the end of processing. Moreover, the inoculated samples exhibited higher levels of fat oxidation-derived aldehydes as well as esters, acids, alcohols and other compounds than the non-inoculated control at the end of the 95-day ripening period. Overall, these findings provide new insights into the application of D. hansenii isolated from dry-cured ham to dry-cured pork belly.

Potential inhibitory effect of carbon dioxide on the spoilage behaviors of Pseudomonas fragi in high-oxygen packaged beef during refrigerated storage

Pseudomonas fragi is a dominant meat spoilage organism under high-oxygen modified atmosphere packaging (HiOx-MAP). This work investigated the effects of CO₂ on P. fragi growth and the related spoilage phenomena of HiOx-MAP beef. Minced beef incubated with P. fragi T1, a strain owning the strongest spoilage potential among isolates, was stored under CO₂-enriched HiOx-MAP (TMAP; 50% O₂/40% CO₂/10% N₂) or non-CO₂ HiOx-MAP (CMAP; 50% O₂/50% N₂) at 4 °C for 14 days. Compared to CMAP, TMAP maintained sufficient O₂ levels to endow beef with higher a* values and meat color stability due to lower P. fragi counts from day 1 (P < 0.05). TMAP samples also showed lower (P < 0.05) lipase activity and protease activity within 14-days and 6-days than CMAP samples respectively. TMAP delayed the significantly increased pH and total volatile basic nitrogen contents occurred in CMAP beef during storage. Despite TMAP markedly promoted the lipid oxidation associated with higher concentrations of hexanal and 2,3-octanedione than CMAP (P < 0.05), TMAP beef retained an acceptable organoleptic odor due to a CO₂-inhibition on the microbial-induced 2,3-butanedione and ethyl 2-butenoate formation. This study provided a comprehensive insight into the antibacterial mechanism of CO₂ on P. fragi in HiOx-MAP beef.

Synergistic Effect of Combination of Various Microbial Hurdles in the Biopreservation of Meat and Meat Products—Systematic Review

The control of spoilage microorganisms and foodborne pathogens in meat and meat products is a challenge for food producers, which potentially can be overcome through the combined use of biopreservatives, in the form of a mix of various microbial hurdles. The objective of this work is to systematically review the available knowledge to reveal whether various microbial hurdles applied in combination can pose an effective decontamination strategy for meat and meat products. PubMed, Web of Science, and Scopus were utilized to identify and evaluate studies through February 2023. Search results yielded 45 articles that met the inclusion criteria. The most common meat biopreservatives were combinations of various starter cultures (24 studies), and the use of mixtures of non-starter protective cultures (13 studies). In addition, studies evaluating antimicrobial combinations of bacteriocins with other bacteriocins, BLIS (bacteriocin-like inhibitory substance), non-starter protective cultures, reuterin, and S-layer protein were included in the review (7 studies). In one study, a biopreservative mixture comprised antifungal protein PgAFP and protective cultures. The literature search revealed a positive effect, in most of the included studies, of the combination of various bacterial antimicrobials in inhibiting the growth of pathogenic and spoilage bacteria in meat products. The main advantages of the synergistic effect achieved were: (1) the induction of a stronger antimicrobial effect, (2) the extension of the spectrum of antibacterial action, and (3) the prevention of the regrowth of undesirable microorganisms. Although further research is required in this area, the combination of various microbial hurdles can pose a green and valuable biopreservation approach for maintaining the safety and quality of meat products.

Effects of the addition of leucine on flavor and quality of sausage fermented by Lactobacillus fermentum YZU-06 and Staphylococcus saprophyticus CGMCC 3475

Methyl-branched aldehydes, especially 3-methylbutanal, have been reported to be perceived either as a malty or as a nutty/chocolate-like aroma and were considered an important flavor contributor in fermented meat products. Decomposition of leucine (Leu) by branched-chain amino acid transaminase (BACT) is a crucial step in the metabolism of Leu to 3-methylbutanal. This study was conducted to explore the effects of mixed-starter culture (Lactobacillus fermentum YZU-06 and Staphylococcus saprophyticus CGMCC 3475) and addition of Leu (0, 1, and 3 mM) on the flavor and quality of fermented sausages. The pH, water activity, texture profile analysis, color, counts of lactic acid bacteria (LAB) and staphylococci, peptide, and flavor compounds were detected during fermentation. The results showed that the starter culture group increased hardness, elasticity, the counts of LAB and staphylococci, peptide content, volatile flavor compounds, as well as the sensorial scores of sausage, while decreasing pH, a _w , and L* and b* values compared with the non-inoculation group. The mixed starter of adding with 3 mM Leu enhanced the content of 3-methylbutanal and overall flavor of fermented sausages. It is applicable to directionally produce methyl-branched aldehydes and improve the overall quality of fermented sausage by the addition of Leu and using starter of L. fermentum YZU-06 and S. saprophyticus CGMCC 3475.

Bifidobacterium animalis A12, a Probiotic Strain That Promotes Glucose and Lipid Metabolism, Improved the Texture and Aroma of the Fermented Sausage

Bifidobacterium animalis A12 was used for the development of fermented sausage. The growth activity, tolerance, and enzyme activity of B. animalis A12 and its contribution to the texture and flavour of fermented sausages were evaluated. Additionally, the sensory texture, flavour components, and amino acid nutrients during the fermentation process were assessed. B. animalis had high tolerance to NaCl and nitrite, and B. animalis A12 had protease and lipase activities. The pH value of sausage fermented with B. animalis A12 was lower than that of sausage fermented without any fermentation strain. Hexanal, heptanal, decanal, cis-2-decanal, and 4-methoxy-benzaldehyde are the unique aldehydes flavour components of fermented sausages in the A12 group. The highest content of volatile flavour substances and amino acids, and the color and texture characteristics of fermented sausage in the experimental group at 18 h were better than those at other times. These results suggest that B. animalis A12 has the potential to be used as a starter culture for im-proving flavour and texture in fermented sausage.

Effect of Starter Cultures on Quality of Fermented Sausages

The expansion and advancement of the meat product market have increased the demand for fermented sausages. A typical method for manufacturing high-quality fermented sausages is using a starter culture, which improves the taste, aroma, and texture. Currently, the starter culture for manufacturing fermented sausages is mainly composed of microorganisms such as lactic acid bacteria, yeast, and fungi, which generate volatile compounds by the oxidation of fatty acids. In addition, protein decomposition and changes in pH occur during the fermentation period. It can positively change the texture of the fermented sausage. In this review, we discuss the requirements (improving food safety, the safety of starter culture, enzyme activity, and color) of microorganisms used in starter cultures and the generation of flavor compounds (heptanal, octanal, nonanal, hexanal, 2-pentylfuran, 1-penten-3-ol, and 2-pentanone) from lipids. Furthermore, quality improvement (hardness and chewiness) due to texture changes after starter culture application during the manufacturing process are discussed.

Effects of Fermentation on the Physicochemical Properties and Aroma of Lamb Liver Paste

The probiotic fermentation of lamb liver paste is a new method with which to utilize sheep by-products and address the issue of waste. In this study, a pH meter, chromaticity meter, texture analyzer, and gas chromatograph–mass spectrometer (GC–MS) were used to determine various indicators. The objective was to investigate the effect of fermentation on the physical properties and aroma of lamb liver paste. The results showed that the L* (brightness), a* (redness), and b* (yellowness) of the samples were significantly higher in the starter fermentation group than in the other two groups after storage for 0, 1, 7, 14, 21, and 28 days (p < 0.05). In addition, cohesiveness, adhesion, and chewiness were lower in the starter fermentation group after 7 days (p < 0.05). TVB-N and fat were lower in the starter fermentation group compared to the sterilization group at 28 days. pH was significantly lower in the starter fermentation group at the beginning of storage, and lactic acid bacteria numbers were significantly higher than in the sterilization groups (p < 0.05). Important aroma compounds, such as 2-undecenal, 1-octen-3-ol, and anethole, were significantly higher in the starter fermentation group than in the sterilization group (p < 0.05). Fermented lamb liver paste is a new by-product that exhibits a high degree of freshness and a low degree of fat oxidation during storage. This study provides a theoretical basis for future industrial production.

Application progress of intelligent flavor sensing system in the production process of fermented foods based on the flavor properties

Fermented foods are sensitive to the production conditions because of microbial and enzymatic activities, which requires intelligent flavor sensing system (IFSS) to monitor and optimize the production process based on the flavor properties. As the simulation system of human olfaction and gustation, IFSS has been widely used in the field of food with the characteristics of nondestructive, pollution-free, and real-time detection. This paper reviews the application of IFSS in the control of fermentation, ripening, and shelf life, and the potential in the identification of quality differences and flavor-producing microbes in fermented foods. The survey found that electronic nose (tongue) is suitable to monitor fermentation process and identify food authenticity in real time based on the changes of flavor profile. Gas chromatography-ion mobility spectrometry and nuclear magnetic resonance technology can be used to analyze the flavor metabolism of fermented foods at various production stages and explore the correlation between flavor substances and microorganisms.

Potential Correlation between Microbial Diversity and Volatile Flavor Compounds in Different Types of Korean Dry-Fermented Sausages

The microbial community in fermented sausages plays an important role in determining their quality characteristics. The objective of this study was to investigate the correlation between microbial diversity and volatile compounds in dry-fermented sausages procured from different regions of Korea. Results from metagenomics analysis showed that Lactobacillus and Staphylococcus were the predominant bacterial genera, and Penicillium, Debaryomyces, and Candida were the predominant fungal genera. Twelve volatile compounds were detected using an electronic nose. Leuconostoc exhibited a positive correlation with esters and volatile flavor, whereas Debaryomyces, Aspergillus, Mucor, and Rhodotorula exhibited a negative correlation with methanethiol, thus revealing the involvement of the microorganisms in flavor formation. The results of this study may help in understanding the microbial diversity of dry-fermented sausages in Korea and provide a rationale and quality control guideline through potential correlation with volatile flavor analysis.

Differences in Fatty Acid Profile and Physical-Chemical Composition of Slavonska slanina-Dry Cured Smoked Bacon Produced from Black Slavonian Pig and Modern Pigs

The objective of this study was to compare the psysico-chemical composition and fatty acid (FFA) profile of traditional dry cured bacon Slavonska slanina, produced from the authentic Black Slavonian Pig (BP) and modern pigs (MP), using traditional homemade principles. The samples of Slavonska slanina produced from BP had a significantly (p < 0.05) higher fat content (78.32%) than the samples produced from MP (46.47%), while the samples produced from MP showed significantly higher (p < 0.05) protein and moisture content. The samples produced from BP also showed lower aw and salt content but higher pH. Determination of fatty acid composition was performed at the end of the production process. The composition of fatty acids with respect to the groups of saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids was determined, as well as the ratios n-6/n-3 and PUFA/SFA. The results of fatty acid composition determination of Slavonska slanina produced from BP and MP show that oleic acid (C18: 1n9) is the most dominant fatty acid from the MUFA group (47.02 and 46.25%), the most common SFA acid was palmitic acid (C16: 0) (23.44 and 24.96%), and PUFA linoleic acid (C18: 2n-6c) (10.76 and 9.74%). The genotype had a significant (p < 0.05) effect on the SFA and USFA composition of Slavonska slanina. The ratios PUFA/SFA (0.34−0.28) and n-6/n-3 (31.84−27.34) for samples of Slavonska slanina produced from BP and MP are in concordance with previously published data for different dry cured meat products, and do not comply with the nutritionally recommended values of international health organizations (PUFA/SFA > 0.4 and n-6/n-3 < 4).

Effects of Lactobacillus plantarum C7 and Staphylococcus warneri S6 on flavor quality and bacterial diversity of fermented meat rice, a traditional Chinese food

Fermented meat rice (FMR) is a traditional Chinese fermented food with special flavor and abundant microorganisms. Lactobacillus and Staphylococcus species have been found to be excellent strains in FMR during fermentation. However, their roles in FMR flavor formation remain yet to be elucidated. Here, we investigated the correlation between physicochemical properties and volatile flavor components, as well as the microbial community during FMR fermentation. First, we determined pH, total titratable acids (TTA), proteins, total lipids, organic acids, free amino acids (FAAs), and volatile flavor compounds (VFCs). With increasing fermentation time, inoculation with Lactobacillus plantarum C7+ Staphylococcus warneri S6 (LP + SW) accelerated the decrease in pH, increased TTA, and reduced protein and total lipid content of FMR. In addition, LP + SW inoculation resulted in significantly (P < 0.05) higher contents of β-eudesmol, nerolidol, ethyl caproate, citronellal, lactic acid, and most FAAs (aspartic acid, glutamic acid, alanine, and lysine) in FMR compared to natural fermentation. Second, inoculated fermentation promoted the growth of Lactobacillus plantarum and/or Staphylococcus warneri and inhibited the growth of some potentially pathogenic microorganisms such as Acinetobacter and Enhydrobacter. Lactobacillus and Staphylococcus were found to be highly correlated with the physicochemical properties and VFCs (P < 0.05) of FMR as indicated by redundancy analysis (RDA) and partial least squares (PLS, VIP > 1.0) analysis. Finally, Spearman's correlation (| r | ≥ 0.7, P < 0.05) analysis of SPSS was visualized by the Cytoscape software. The findings suggest that inoculation with L. plantarum C7 and/or S. warneri S6 can significantly improve the flavor quality of FMR.

Effect of Mixed Starters on Proteolysis and Formation of Biogenic Amines in Dry Fermented Mutton Sausages

In this study, by comparing the four groups of sausages, namely, CO (without starter culture), LB (with Lactobacillus sakei), LS (with L. sakei 3X-2B + Staphylococcus xylosus SZ-8), and LSS (with L. sakei 3X-2B + S. xylosus SZ-8 + S. carnosus SZ-2), the effects of mixed starter cultures on physical-chemical quality, proteolysis, and biogenic amines (BAs) during fermentation and ripening were investigated. Inoculation of the mixed starter cultures increased the number of lactic acid bacteria and staphylococci in sausages during fermentation and ripening for 0 to 5 days. The L. sakei 3X-2B + S. xylosus SZ-8 + S. carnosus SZ-2 mixed starter accelerated the rate of acid production and water activity reduction of sausages and improved the redness value. Compared with CO, the mixed starter effectively inhibited Enterobacteriaceae. At the end of ripening, the LSS group was approximately 1.25 CFU/g, which was less than the CO group, thereby reducing the total volatile basic nitrogen (TVB-N) in the LSS group. The free amino acids in the LS and LSS groups (224.97 and 235.53 mg/kg dry sausage, respectively) were significantly (p < 0.001) higher than that in the CO group (170.93 mg/kg dry sausage). The level of histamine, cadaverine, putrescine, and common BAs showed an opposite trend to the increase of the corresponding precursor amino acid content, which were significantly lower (p < 0.001) in the LS and LSS sausages than in CO. This study showed that L. sakei 3X-2B + S. xylosus SZ-8 + S. carnosus SZ-2 is a potential mixed starter for fermented meat products.

Incorporation of Selected Strains of Pediococcus spp. on Quality Characteristics of Dry Fermented Sausage during Fermentation and Ripening

This research investigated the physio-chemical and microbial quality characteristics of dry fermented sausage from selected Pediococcus strains: P. acidiliactici (PE1) and P. pentosaceus (PE2) as compared to commercial starter culture (COS) during fermentation and ripening. Treatments showed no substantial variation (p<0.05) in water activity (a_w) values across the study period. PE1 and PE2 treatments exhibited similar (p>0.05) pH values and presented remarkable (p<0.05) lower volatile basic nitrogen (VBN) and thiobarbituric acid reactive (TBARS) content than COS treatment throughout the ripening period. However, the pH values in COS batch were considerably lower than others. PE1 samples presented a significant highest (p<0.05) counts both in lactic acid bacteria (LAB) and total plate count (TPC) than COS and PE2 treatments at 7 days fermentation, and it resulted in a similar and higher TPC count as COS after the ripening period. After the ripening process, treatments are ordered based on LAB counts as follows: COS>PE1>PE2. All batches presented similar redness and yellowness attributes since the 7 days of fermentation and in lightness across the study period. Treatments were similar (p>0.05) in springiness and chewiness traits across the study period and in hardness characteristics in the ripened products. Cohesiveness was higher in PE1 and COS batches. No variation (p>0.05) in aroma and sourness sensory attributes of treatments. The color attribute was highest (p<0.05) in PE1 and PE2 treatments and PE1 had the highest overall acceptability. The overall outstanding merit exhibited by PE1 can be utilized in the commercial production of high-quality dry fermented sausage.

Effect of probiotic Lactiplantibacillus plantarum and chestnut flour (Castanea sativa mill) on microbiological and physicochemical characteristics of dry-cured sausages during storage

The effect of chestnut flour (Castanea sativa Mill) on L. plantarum viability and physicochemical characteristics in a dry-cured sausage (Longaniza de Pascua) during storage is discussed. Four batches were prepared: CL with 3% chestnut flour added; CPL with 3% chestnut flour and 8.5 log CFU/g L. plantarum added; PL with 8.5 log CFU/g L. plantarum added and L, the batch control. The sausages were stored at 4 °C and 20 °C, and vacuum packed for 43 d. L. plantarum viability was affected by storage time (P < 0.001). However, higher L. plantarum counts at the final of storage were reached due to chestnut flour addition (P < 0.001). At room storage, chestnut flour caused a higher increase in TBARS values (P = 0.022). Nevertheless, all lipid oxidation treatments were in the range of accepted values at the sensory detection level. In conclusion, Longaniza de Pascua can be kept at 4 °C or 20 °C for 43 d without causing any rancidity problems.

Changes in the microbiological, physicochemical properties of Chinese traditional fermented Suan rou at ripening fermentation

This study characterized the changes in the microbiological, physicochemical properties of Suan rou during fermentation via three different techniques (Technique A is a traditional production process. Based on technique A, technique B adds a total of 200 g of sucrose to the thinly sliced meat, and technique C changes the amount of salt in the thinly sliced meat to 200 grams.). Compared to batch A, the samples from batches B and C featured more rapid reduction in pH and generated more TA. Myofibrillar proteins in batches B and C showed higher degradation rate, and several low-molecular-weight metabolites were determined on the basis of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) gel lanes. The contents of thiobarbituric acid (TBARS) and total volatile base nitrogen (TVB-N) and the growth of spoilage bacteria and pathogens were suppressed in the three batches. A relatively compatible acid-salinity proportion was presented in the Suan rou of batches A and B compared with that of batch C. The results show that the Suan rou made by B technology was more palatable acid flavor and abundant nutrition.

Effect of Different Pediococcus pentosaceus and Lactobacillus plantarum Strains on Quality Characteristics of Dry Fermented Sausage after Completion of Ripening Period

The aim of this study was to evaluate the effect of three different strains of lactic acid bacteria (LAB) starter cultures: Pediococcus pentosaceus (KC-13100) (PP), Lactobacillus plantarum (KCTC-21004) (LP1), and L. plantarum (KCTC-13093) (LP2) on the physicochemical and microbiological characteristics, and sensory quality of dry fermented sausages after 21 days of drying and ripening period. Treatments added with PP and LP2 strains showed a significant higher (p<0.05) LAB and total plat counts, and water activity (a_w) of all three treatments was below 0.85 after the completion of the ripening process. A significant variation (p<0.05) in pH values of treatments was exhibited due to the difference in acidification capacity of the LAB strains: LP2<PP<LP1. Treatments had significant difference (p<0.05) in the thiobarbituric acid reactive substances (TBARS) content, in the following order: LP1>PP>LP2. Substantial variations (p<0.05) in shear force values were detected amongst three batches (LP2>LP1>PP). In sensory attributes, PP treated samples had significantly higher (p<0.05) color and overall acceptability scores. The current findings proved how important the optimal assortment of starter culture. Inoculation with PP produced importantly beneficial effects on sensory quality improvement of dry fermented sausage.

A comprehensive review of the role of microorganisms on texture change, flavor and biogenic amines formation in fermented meat with their action mechanisms and safety

Meat fermentation ensures its preservation, improved safety and quality. This prominently used traditional process has survived for ages, creating physical, biochemical, and microbial changes, and to significantly affect the functionality, organoleptic property, and nutrition of the fermented products. In some process, the growth of various pathogenic and spoilage microorganisms is inhibited. The production of fermented meat relies on naturally occurring enzymes (in the muscle or the intestinal tract) as well as microbial metabolic activities. In this review, fermented meat types and their health benefits were firstly introduced. This was followed by a description of fermentation conditions vis-à-vis starters, bacterial, yeast and mold cultures, and their role in meat. The review focuses on how microorganisms affect texture change, flavor formation, and biogenic amines (BA) accumulation in fermented meat. In addition, the production conditions and the major biochemical changes in fermented meat products were also introduced to present the best factors influencing the quality of fermented meat. Microorganisms and microbial enzymes in fermented meats were discussed as they could affect organoleptic characteristics of fermented meats. Moreover, safety concerns and prospects for further research of fermented meat were also discussed with emphasis on novel probiotic and starter cultures development; bioinformatics, omics technologies and data modeling to maximize the benefit from fermentation process in meat production.

Effect of Lactobacillus plantarum on antioxidant activity in fermented sausage

This study investigated in vitro antioxidant activity of Lactobacillus plantarum CD101 and its effect on antioxidant peptides formation in fermented sausage. The antioxidant substances of L. plantarum CD101 were mainly distributed on the cell surface and extracellular secretions. L. plantarum CD101 affected the acidification and proteolysis during the fermentation. Combined with electrophoresis and peptide content analysis, these results indicated the effectiveness of the starters in promoting peptide formation, accompanied by a small change in antioxidant activities. Forty-four effective peptides were identified by LC-MS/MS. The masses of the peptides were less than 3 kDa, and their amino acid sequences were between 5 and 27 amino acids in length. Thus, L. plantarum CD101 may be beneficial to inhibit the oxidative rancidity of fermented sausage through its in vitro antioxidant activity, while effectively promoting protein degradation with a weak effect on antioxidant peptides promotion.

Screening and optimization of a nitrate reductase-producing Staphylococcus simulans UV-11 and its application

A strain of Staphylococcus simulans D14 (S. simulans D14) showed the highest nitrate reductase activity (NRA) of 4.52 mM NO₂⁻/mg dry weight by the spectrophotometric method, which was screened from traditional Chinese sausage. When the UV mutagenesis time was 25 s, the positive mutation rate was the highest at 26.60%. The NRA of the obtained positive mutant UV-11 was 9.21 mM NO₂⁻/mg dry weight, and the activity was found to be 1.04-fold higher than that of the original strain S. simulans D14. A Plackett–Burman design (PBD) was employed to screen the significant variables pH, KNO₃ (%) and incubation time (h), and response surface methodology (RSM) was used to optimize the significant variables using a Box–Behnken design (BBD). The results showed that the NRA of S. simulans UV-11 was 15.22 mM NO₂⁻/mg dry weight under optimum conditions of 37 °C, pH 6.5, incubation time 15 h, KNO₃ 0.045%, NaCl 5%, NaNO₂ 0.015%, peptone 1%, and D–mannitol 1%, which increased by 65.2% compared with the unoptimized medium. Natural curing agents (containing 10⁷ CFU/g S. simulans UV-11 under optimal conditions and 1.40% celery powder, T2) were added to the cured meat model. T2 produced significantly lighter and redder signals than the control group (C) and the addition of 150 ppm NaNO₂ group (T1). The thiobarbituric acid reactive substance (TBARS) of T2 was 2.30 mg malonaldehyde/kg product and residual nitrite of T2 was 7.1 ppm after 14 days of storage,which were lower than those groups of C and T1. Taking into account the results of cured meat models, S. simulans UV-11 could be selected as a potential starter culture for the processing of natural meat products.

Functional Characteristics of Lactobacillus and Yeast Single Starter Cultures in the Ripening Process of Dry Fermented Sausage

Dry fermented sausage is popular among the world because of its rich nutrition and unique flavor. Starter cultures play an important role in the quality of dry fermented sausage. In this study, probiotics lactic acid bacteria Lactobacillus delbrueckii N102, Latilactobacillus sakei H1-5, Debaryomyces hansenii Y4-1, and Wickerhamomyces anomalus Y12-3 were isolated from food-borne materials. The physicochemical properties, microbial populations, TBARS, lipolysis, proteolysis, and volatile flavor compounds of dry fermented sausages with different starter cultures were evaluated comparatively during the ripening process. The results showed that both L. delbrueckii N102 and L. sakei H1-5 grow well and could rapidly reduce the pH value of the products. At the same time, they could significantly reduce the number of Enterobacter putrefaciens, so as to ensure the safety of the products. In addition, the strains N102 promoted the formation of flavor compounds 2,3-butanedione, 3-hydroxy-2-butanone, and carnosine, whereas taurine content of batch H1-5 was significantly increased, while yeast y4-1 and y12-3 could also grow faster in sausage and promoted the esters and alcohols formation such as ethyl acetate and linalool, with the formation of γ-aminobutyric acid by y4-1. Compared with lactic acid bacteria, yeasts showed to contribute more in flavor formation and effective inhibition of lipid oxidation. The starter cultures played different roles in flavor contribution and had obvious differentiation in the ripening process of dry fermented sausage.

Biochemical Changes during the Manufacture of Galician Chorizo Sausage as Affected by the Addition of Autochthonous Starter Cultures

In this work, the effect of the use of two autochthonous starter cultures (Lactobacillus sakei LS131 + Staphylococcus equorum SA25 (EQU), or L. sakei LS131 + Staphylococcus saprophyticus SB12 (SAP)) on the physicochemical, microbiological, proteolytic and lipolytic changes taking place during the manufacture of Galician chorizo, a traditional Spanish sausage, was studied. Three different batches (control (CNT), EQU and SAP) were manufactured in triplicate and analysed during the manufacturing process (samples were taken and analysed at 0, 2, 5, 9, 14, 21 and 30 days of ripening) for proximate composition, pH, aw, colour parameters, nitrogen fractions, free amino acids, biogenic amines, fat parameters and free fatty acids. The use of either of these two starter cultures slightly but significantly reduced the pH values during the fermentation and increased the percentage of transformation to nitrosyl-heme pigments as well as the a* and b* values in the final products. The two starters significantly decreased the Enterobacteriaceae counts in the final product, but without this microbial group completely disappearing. Both starter cultures significantly increased the α-amino acidic nitrogen and the total basic volatile nitrogen fractions during manufacturing, also increasing the free amino acid content and reducing the total biogenic amine content by approximately 20%. The SAP starter enhanced the lipolytic processes, increasing the free fatty acid content. Due to their performances, these two starter cultures seem to be suitable for increasing the quality and safety of the Galician chorizo sausage.

Biogenic amine content during the production and ripening of Sremski kulen, Serbian traditional dry fermented sausage

Sremski kulen is a wide diameter dry fermented sausage, produced from pork, seasoned with red spicy paprika, stuffed into pork cecum, and preserved by smoking, fermentation and drying. Due to specific ripening process, Sremski kulen is suitable for the accumulation of biogenic amines. Therefore, the aminogenesis was studied in traditionally produced Sremski kulen, taking into account the physicochemical parameters and microbial counts. The content of six biogenic amines (tryptamine, phenylethylamine, tyramine, histamine, putrescine, and cadaverine) was analyzed using high-performance liquid chromatography. The ripening process of Sremski kulen was slow followed by changes in a_w and pH value as well as expressed proteolysis. The autochthonous microbiota showed pronounced decarboxylase activity. Tryptamine and phenylethylamine were detected at each examined ripening stage while histamine was not detected until the end of ripening (16.55 ± 2.33 mg/kg). Tyramine, cadaverine, and putrescine content significantly increased during the ripening period (p < .05). In the final product, cadaverine was the dominant biogenic amine (132.40 ± 5.05 mg/kg), followed by tyramine (115.80 ± 15.46 mg/kg) and putrescine (68.55 ± 2.39 mg/kg). Although the long ripening period greatly contributed to the accumulation of biogenic amines in final product, their content are not of concern from product safety aspects, but requires improvement in hygiene of production process.

Effect of fermentation by various bacterial strains on quality of dried duck meat slice

The effects of fermentation on the sensory qualities, lipid oxidation, harmful substances, and microbial growth of dried duck meat slice (DDMS) were investigated. The results showed that the optimal fermentation was controlled at 22.18 °C for 49.15 h with the mixed inoculation (7.09 log CFU/g) of Lactobacillus acidophilus and Pediococcus pentosaceus (2:1). Under the optimal fermentation conditions, the fermented DDMS presented higher scores of color (9.0 ± 0.16), aroma (8.8 ± 0.35), and total (8.9 ± 0.24) with lower hardness (5316 ± 98.80 g), compared to control (8.6 ± 0.21, 8.3 ± 0.26, 8.4 ± 0.08, and 7016 ± 114.17 g, respectively). Meanwhile, the histamine content decreased, and the nitrite content was reduced by nearly 60% in fermented DDMS. The lipid oxidation and microbial growth (Escherichia coli, mold, and yeast) in DDMS were also inhibited by fermentation. It provides useful data for improving the quality and safety of meat products.

Isolation, identification and characterization of Staphylococcus sp. from Indian ethnic fermented fish product

Staphylococci from Sheedal of Northeast India was isolated, identified and characterized. All the isolated staphylococci were found to be coagulase negative. Based on the rpoB gene sequences followed by analysis using NCBI-BLAST software, seven species of Staphylococcus namely, S. piscifermentans, S. condimenti, S. arlettae, S. sciuri, S. warneri, S. nepalensis and S. hominis were recognized. Phylogenetic analyses revealed three major cluster groups. All the seven Staphylococcus showed their NaCl tolerance from 2 to 8%. No species was able to grow at 55°C. Except S. arlettae and S. sciuri, all the isolated staphylococcal species exhibited growth at pH 4-8. No isolated species was able to ferment mannitol, sucrose and arabinose. All the species exhibited moderate to maximum proteolytic and lipolytic activities. All the seven species were found to be sensitive to the antibiotics, namely, erythromycin, norfloxacin, ampicillin, streptomycin and vancomycin, whereas all were resistant to co-trimoxazole. Only S. piscifermentans was found antagonist to Salmonella enterica, Escherichia coli and Bacillus subtilis, although the clear zone was minimal. All the staphylococcal species except S. arlettae and S. sciuri exhibited hydrophobicity ranging from 25 to 66%. The observed characteristics of isolated Staphylococci from Sheedal revealed their role in fish fermentation.

Effect of chitosan-essential oil, a surface mold inhibitor, on microbiological and physicochemical characteristics of semidried fermented sausages

Mold growth on sausage casing during processing is an important problem in fermented sausages. In this work, sausages were dipped into 1% chitosan (C), 1% thyme essential oil in 1% chitosan (CT), 1% rosemary essential oil in 1% chitosan (CR), 20% potassium sorbate (PS) as chemical antifungal, and 1% acetic acid solution (AA) as chitosan solver, or distilled water (DW) as control after fermentation (at day 4). The changes in microbiological (total viable count, lactic acid bacteria [LAB], Micrococcaceae, Enterobacteriaceae, and mold and yeast counts) and physicochemical attributes of the sausages during 12 days of processing were monitored. As expected, LAB were the most dominant microbiota in fermented sausages and the dipping process did not have any negative effect. Additionally, the treatment with C, CT, and CR suppressed the growth of spoilage microorganisms, which resulted in a significant reduction (P < 0.01) of about 1.4 to 1.6 log CFU/g in Enterobacteriaceae counts at day 12. The C, CT, and CR similarly suppressed the growth of fungi in the interior of the sausages, and the antifungal treatment significantly reduced (P < 0.01) the load of fungi on the casing. Throughout the study, approximately log counts of 3 and 4 in lower molds and yeasts in the casings treated with PS and CR were found, respectively, as compared to DW. Finally, the microbial quality of the end product was notably improved. PRACTICAL APPLICATION: Processing conditions such as high humidity and O₂ in the ripening chamber result in undesirable fungal growth on the casings of the sausages. Fermented sausages are usually treated with weak acids such as sorbic or benzoic acids or their salts to inhibit mold growth during the drying process. However, increasing consumer demand to reduce the use of chemicals encourages the applications of natural antifungals.

Lactic Acid Bacteria: Variability Due to Different Pork Breeds, Breeding Systems and Fermented Sausage Production Technology

Changes in the ecology of the various lactic acid bacteria (LAB) species, which are involved in traditional fermented sausages, were investigated in the light of the use of different breeds of pork, each of which was raised in two different environments and processed using two different technologies. The semi-quantitative molecular method was applied in order to understand how the different species alternate over time, as well as their concentration ratios. A significant increase in LAB over the first days of fermentation characterized the trials where the starter culture wasn't added (T), reaching values of 107-108 cfu g-1. On the other hand, in the trials in which sausages were produced with starter addition, LAB counts had a less significant incremental jump from about 106 cfu g-1 (concentration of the inoculum) to 108 cfu g-1. Lactobacillus sakei and Lb. curvatus were detected as the prevalent population in all the observed fermentations. Pediococcus pentosaceus, Lb. casei, Leuconostoc mesenteroides, Lactococcus garviae, and Lb. graminis also appeared, but their concentration ratios varied depending on the diverse experimental settings. The results of cluster analysis showed that a plant- and breed-specific LAB ecology exists. In addition, it was also observed that the breeding system can influence the presence of certain LAB species.

Evaluation of linseed oil oleogels to partially replace pork backfat in fermented sausages

BACKGROUND

Nowadays, fat replacement in meat products is a matter of concern in the meat industry. The objective of this study was to evaluate the replacement of pork backfat with two oleogels of linseed in dry-cured sausages.

RESULTS

Five batches of dry-cured sausages were prepared with two oleogels, a mixture of γ-oryzanol and β-sitosterol (SO) and beeswax (B), at two levels of replacement (20% and 40%) (SO-20, SO-40, B-20, and B-40, respectively) and a control batch. The fatty acid profile improved in terms of nutrition: the polyunsaturated fatty acid / saturated fatty acid (PUFA/SFA) and n-6/n-3 ratio was about 1.41 and 0.93 for the higher levels of replacement, SO-40 and B-40, respectively. Quality parameters such as pH and color also changed with the inclusion of oleogels, resulting in changes in the sensory quality.

CONCLUSION

Oleogels based on linseed enabled the replacement of pork backfat in fermented sausages. Depending on the level of fat substitution, such oleogels could replace fat in dry-cured sausages at the industrial level. © 2019 Society of Chemical Industry.

MODERN PRODUCTION TRENDS OF FERMENTED MEAT PRODUCTS

The work aims to the generalization and analysis of the main problems of production of fermented meat products, which are reflected in scientific publications of the meat processing industry experts. The modern researches of scientists all over the world are aimed to the achievement of bio- and microbiological safety, structure formation, use of new kinds of raw materials, features of color formation, formation of sensory properties, increase of biological value of smoked and uncooked products. The work emphasizes that the quality of finished products and the stability of the technological process depends on the quality of raw materials, the properties of their own microbiota of raw materials and/or introduced starter cultures of microorganisms. The possibility of improving the sanitary condition of raw materials and reducing the impact of pathogenic microorganisms due to the use of ultrasound, hydrostatic high pressure, high-intensity pulsating electric field, cold plasma are described in the work. Also, in addition to physical processing methods, the use of competing microflora, extracts of spicy-aromatic plants, combining salt mixtures, packaging are effective. It is stated that the formation of the structure of the finished product depends on the parameters of the technological process, the activity of exo-endoenzymes and prescription composition. It is shown that the color of fermented meat products and their stability depend on the content of natural pigments and the conditions of their interaction with nitrites under the action of microorganisms with nitrite reductase activity and pH of the environment. The possibility of obtaining a characteristic pink-red color of meat products without the use of nitrites was noted. The results of investigations of the possibility of varying the organoleptic parameters of the finished product by modeling the ingredient composition and fermentation conditions are presented. The possibilities of creation of new types of fermented meat products of functional purpose by the introduction of ω-3 fatty acids, probiotics, macro-, microelements and more are described.

Evolution of indigenous starter microorganisms and physicochemical parameters in spontaneously fermented beef, horse, wild boar and pork salamis produced under controlled conditions

The present work was carried out to evaluate the microbiological and physicochemical composition of salamis produced with the meat of beef, horse, wild boar and pork. Salami productions occurred under controlled laboratory conditions to exclude butchery environmental contaminations, without the addition of nitrate and nitrite. All trials were monitored during the ripening (13 °C and 90% relative humidity) extended until 45 d. The evolution of physicochemical parameters showed that beef and pork salamis were characterized by a higher content of branched chain fatty acids (FA) and rumenic acid than horse and wild boar salamis, whereas the last two productions showed higher values of secondary lipid oxidation. Plate counts showed that lactic acid bacteria (LAB), yeasts and coagulase-negative staphylococci (CNS) populations dominated the microbial community of all productions with Lactobacillus and Staphylococcus as most frequently isolated bacteria. The microbial diversity evaluated by MiSeq Illumina showed the presence of members of Gammaproteobacteria phylum, Moraxellaceae family, Acinetobacter, Pseudomonas, Carnobacterium and Enterococcus in all salamis. This study showed the natural evolution of indigenous fermented meat starter cultures and confirmed a higher suitability of horse and beef meat for nitrate/nitrite free salami production due to their hygienic quality at 30 d.

Impact of fructooligosaccharides and probiotic strains on the quality parameters of low-fat Spanish Salchichón

The substitution of dietary fiber and probiotic strains to reduce fat content of fermented sausages has been used for the development of innovative and healthier meat products. For this study, pork back fat was partially replaced by fructooligosaccharides (FOS) and the probiotic strains Lactobacillus paracasei and Lactobacillus rhamanosus. The fat replacement resulted in a significant decrease (P ≤ .05) in fat content (29%) compared with the control formulation (no fat substitution). The addition of FOS did not have a significant effect on microbial counts; however, reductions in Enterobacteriaceae and yeast were observed when Lactobacillus strains were also incorporated. The inclusion of FOS and probiotic strains did not show any significant effect on lipid oxidation and proteolysis. The partial fat replacement and the addition of Lactobacillus rhamanosus GG as probiotic strain in Spanish Salchichón can be considered a successful reformulation strategy for the meat product market.

The Influence of Meat Batter Composition and Sausage Diameter on Microbiota and Sensory Traits of Artisanal Wild Boar Meat Sausages

In this study, the influence of meat batter composition and sausage diameter on the development of microbiota and sensory traits of traditional, spontaneously fermented wild boar meat sausages are evaluated. This research also demonstrates how principal component analysis (PCA) can be used to relate product sensory properties to particular microbial genotype and to select potential starter or adjunct culture. Generally, similar microbiological results were obtained in all types of products. The undesirable microbiota was either not detected at any sausage production stage or its number decreased below the detection limit in ripened sausages. The low growth rate of lactic acid bacteria (LAB) was consistent with the obtained pH and slow acidification rate. Although no differences in the composition of LAB species were noticed between sausage types (50S=50% wild boar meat in small casing, 50L=50% wild boar meat in large casing, 100S=100% wild boar meat in small casing), a clear separation based on LAB genotypes could be observed. Upon quantitative descriptive analysis, significant differences in sensory attributes between sausage types were established. According to the PCA, the overall acceptability traits of sausages are closely linked to one Leuconostoc mesenteroides genotype (LM_4). Of all tested technological properties, LM_4 strains showed remarkable acidification ability, lowering the pH from pH=5.41 to 3.74, and pronounced proteolytic activity on skimmed milk as well as antagonistic activity against Staphylococcus aureus (DSM 20231) and Brochothrix thermosphacta (LMG 17208). Lipolytic and haemolytic activities were not detected, and all analyzed strains were susceptible to tested antibiotics and possessed no biogenic amine genes.

Effects of different starter culture combinations on microbial counts and physico-chemical properties in dry fermented mutton sausages

This study was conducted to evaluate the effects of inoculation with different mixed starter culture combinations on microbial counts, physico-chemical properties, and proteolytic and lipolytic properties of dry fermented mutton sausages during fermentation and ripening. Four different batches of mutton sausages were manufactured: CO batch, no starter cultures, used as control; LB batch with Lactobacillus sakei; LS batch with L. sakei + Staphylococcus xylosus; and LSS batch with L. sakei + S. xylosus + Staphylococcus carnosus. The results showed that adding starter culture caused Lactobacillus and Staphylococcus to become dominant bacteria and reduced the Enterobacteriaceae count in the inoculated sausages. The mixed starter cultures (LS & LSS) accelerated acidification and reduced water activity and lipid oxidation. Statistical analysis revealed that the use of mixed starter cultures, especially the combination L. sakei + S. xylosus + S. carnosus, contributed to proteolysis and lipolysis, increasing total free amino acids and polyunsaturated fatty acids. The above results demonstrate that the use of mixed starter cultures contributes to improving the composition of free amino acids and free fatty acids as well as the hygienic quality of dry fermented mutton sausages.