Application of Lactobacillus fermentum HL57 and Pediococcus acidilactici SP979 as potential probiotics in the manufacture of traditional Iberian dry-fermented sausages

Impact of Pediococcus acidilactici GLP06 supplementation on gut microbes and metabolites in adult beagles: a comparative analysis

There is growing interest in the potential health benefits of probiotics for both humans and animals. The study aimed to investigate the effects of feeding the canine-derived probiotic Pediococcus acidilactici GLP06 to adult beagles by analysing the microbiome and metabolome. Twenty-four healthy adult beagles were randomly assigned to four groups. The CK group received a standard diet, while the three probiotic groups, the LG group (2 × 108 CFU/day/dog), MG group (2 × 109 CFU/day/dog), and HG group (2 × 1010 CFU/day/dog), received the standard diet supplemented with varying amounts of probiotics. The results show that, compared to the CK group, total antioxidant capacity was significantly increased in the MG and HG groups (p < 0.05), and superoxide dismutase and catalase were significantly increased in the HG group (p < 0.05). Compared to the CK group, malondialdehyde and blood urea nitrogen content were significantly decreased in the MG and HG groups (p < 0.05). Additionally, secretory immunoglobulin A activity was significantly increased in the HG group compared to the CK and LG groups (p < 0.05), and immunoglobulin G activity was significantly increased in the HG group compared to the CK, LG, and MG groups (p < 0.05). In addition, compared with the CK group, the abundance of Faecalitalea and Collinsella increased in the LG group, and the relative abundance of Tyzzerella and Parasutterella increased in the MG group. The α diversity and the relative abundances of beneficial bacteria (Faecalibacterium, Lachnospiraceae_NK4A1316, and Ruminococcaceae_UCG-005) were higher in the HG group than in the CK group. Furthermore, acetic acid content was significantly increased in the HG group compared to the CK, LG, and MG groups (p < 0.05). Butyric acid, isobutyric acid, and the total SCFA content were significantly increased in the HG group compared to the CK group (p < 0.05). Moreover, metabolome analysis revealed 111 upregulated and 171 downregulated metabolites in the HG group. In conclusion, this study presents evidence that supplementing with P. acidilactici GLP06 can have a positive impact on antioxidant activity, immunoproteins, SCFAs, and gut microbiota in adult beagles. These findings highlight the potential of probiotics as a dietary intervention to enhance gut health and overall wellbeing in companion animals.

Bacterial microbiota in different types of processed meat products: diversity, adaptation, and co-occurrence

As a double-edged sword, some bacterial microbes can improve the quality and shelf life of meat products, but others mainly responsible for deterioration of the safety and quality of meat products. This review aims to present a landscape of the bacterial microbiota in different types of processed meat products. After demonstrating a panoramic view of the bacterial genera in meat products, the diversity of bacterial microbiota was evaluated in two dimensions, namely different types of processed meat products and different meats. Then, the influence of environmental factors on bacterial communities was evaluated according to the storage temperature, packaging conditions, and sterilization methods. Furthermore, microbes are not independent. To explore interactions among those genera, co-occurrence patterns were examined. In these respects, this review highlighted the recent advances in fundamental principles that underlie the environmental adaption tricks and why some species tend to occur together frequently, such as metabolic cross-feeding, co-aggregate at microscale, and the intercellular signaling system. Further investigations are required to unveil the underlying molecular mechanisms that govern microbial community systems, ultimately contributing to developing new strategies to harness beneficial microorganisms and control harmful microorganisms.

The Impact of HPP-Assisted Biocontrol Approach on the Bacterial Communities' Dynamics and Quality Parameters of a Fermented Meat Sausage Model

Traditional foods are increasingly valued by consumers, whose attention and purchase willingness are highly influenced by other claims such as 'natural', 'sustainable', and 'clean label'. The purpose of the present study was to evaluate the impact of a novel non-thermal food processing method (i.e., HPP-assisted biocontrol combining mild high hydrostatic pressure, listeriophage Listex, and pediocin PA-1 producing Pediococcus acidilactici) on the succession of bacterial communities and quality of a fermented sausage model. A comparative analysis of instrumental color, texture, and lipid peroxidation revealed no significant differences (p > 0.05) in these quality parameters between non- and minimally processed fermented sausages throughout 60-day refrigerated storage (4 °C). The microbiota dynamics of biotreated and untreated fermented sausages were assessed by 16S rRNA next-generation sequencing, and the alpha and beta diversity analyses revealed no dissimilarity in the structure and composition of the bacterial communities over the analyzed period. The innovative multi-hurdle technology proposed herein holds valuable potential for the manufacture of traditional fermented sausages while preserving their unique intrinsic characteristics.

Screening and Constructing a Library of Promoter-5'-UTR Complexes with Gradient Strength in Pediococcus acidilactici

The GRAS (generally recognized as safe) strain Pediococcus acidilactici is well known for its antibacterial and probiotic functions. Furthermore, as P. acidilactici has excellent high temperature and salt resistance, it is an ideal host for the production of food enzymes, food additives, and pharmaceuticals. In this regard, it is desirable and feasible to enhance the production of these products through the metabolic engineering of P. acidilactici. However, the rare gene expression elements greatly obstruct the development of engineering P. acidilactici. In this study, we screened and constructed a library of promoter-5'-UTR (PUTR) complexes in P. acidilactici DY15 for regulating gene expression at the transcription and translation levels. In the post-log phase, the mRNA and protein expression level ranges of the 90 screened native PUTRs were 0.059-2010% and 0.77-245%, respectively, of the P32 promoter. Besides, several PUTRs exhibited great expression stability under high temperature, salt, and ethanol stress. We analyzed the structure of PUTRs and obtained the conserved regions of the promoter and 5'-UTR. Based on the identified core regions of PUTRs, we constructed a panel of combinatorial PUTRs with higher and stable protein expression levels. The strongest combinatorial PUTR was 853% of the P32 promoter in the protein expression level. Finally, the obtained PUTRs were applied to optimize the expression level of aminotransferase and improve the phenyllactic acid (PLA) production in P. acidilactici DY15. The achieved yield was 950.6 mg/L, which was 79.2% higher than the wild-type strain. These results indicated that the obtained PUTRs with gradient strength had great potential for precisely regulating gene expression to achieve various goals in P. acidilactici.

Changes in Bio-Functional Compounds, ACE Inhibition, and Antioxidant Capacity after Mixed Fermentation of Eight Whole Grains

Whole grains are rich in nutrients and antioxidants and can be fermented to increase their biological functions. This study used two fermentation steps to ferment eight whole grains. The bio-functional compounds, ACE inhibition, and antioxidant capacity were measured during the second fermentation step. The results indicate that the total phenols content increased by 2605%, total flavonoid content increased by 1707%, ABTS radical scavenging capacity increased by 239%, DPPH radical scavenging capacity increased by 325%, GABA increased by 4810%, glucuronic acid increased by 4278%, ACE inhibition increased by 69.28%, and total amino acids increased by 2197.72% after 13 weeks of fermentation. These results showed that a fermentation beverage with eight whole grains could be considered a drink with health benefits.

Investigating the effect on biogenic amines, nitrite, and N-nitrosamine degradation in cultured sausage ripening through inoculation of Staphylococcus xylosus and lactic acid bacteria

Introduction

Microbial inoculants can reinvent the value and edible security of cultured sausages. Various studies have demonstrated that starter cultures made up of Lactic acid bacteria (LAB) and Staphylococcus xylosus (known as L-S) isolated from traditional fermented foods were used in fermented sausage manufacturing.

Methods

This study evaluated the impact of the mixed inoculation cultures on limiting biogenic amines, nitrite depletion, N-nitrosamine reduction, and quality metrics. Inoculation of sausages with the commercial starter culture (SBM-52) was evaluated for comparison.

Results and discussion

Results showed that the L-S strains could rapidly decrease the water activity (Aw) and pH of fermented sausages. The ability of the L-S strains to delay lipid oxidation was equivalent to the SBM-52 strains. The non-protein nitrogen (NPN) contents of L-S-inoculated sausages (0.31%) were higher than that of SBM-52-inoculated sausages (0.28%). After the ripening process, the nitrite residues in the L-S sausages were 1.47 mg/kg lower than in the SBM-52 sausages. Compared to the SBM-52 sausages, there was a 4.88 mg/kg reduction in the biogenic amines' concentrations in L-S sausage, especially for histamine and phenylethylamine concentrations. The N-nitrosamine accumulations of the L-S sausages (3.40 ug/kg) were lower than that of the SBM-52 sausages (3.70 ug/kg), and the NDPhA accumulations of the L-S sausages were 0.64 ug/kg lower than that of the SBM-52 sausages. Due to their significant contributions to nitrite depletion, biogenic amine reduction, and N-nitrosamine depletion in fermented sausages, the L-S strains have the potential to serve as an initial inoculant in the process of manufacturing fermented sausages.

Spray Drying Encapsulation of Pediococcus acidilactici at Different Inlet Air Temperatures and Wall Material Ratios

Pediococcus acidilactici has gained research and commercial interest due to its outstanding probiotic properties, yet its survival during storage and consumption requires improvement. This study aims to enhance P. acidilactici survival using spray drying encapsulation. Different inlet air temperatures (120 °C, 150 °C, and 170 °C) and whey protein isolate (WPI):gum arabic (GA) ratios (1:1, 3:1, 1:3) were tested. Cell viability was significantly (p < 0.05) affected by the inlet temperature but not the WPI:GA ratio. Increasing the inlet temperature to 170 °C significantly decreased P. acidilactici viability by 1.36 log cycles, from 8.61 log CFU/g to 7.25 log CFU/g. The inlet temperature of 150 °C resulted in a powder yield (63.12%) higher than at 120 °C (58.97%), as well as significantly (p < 0.05) lower moisture content (5.71%) and water activity (aw 0.21). Viable cell counts in all encapsulated P. acidilactici were maintained at 5.24−6.75 log CFU/g after gastrointestinal tract (GIT) simulation, with WPI:GA of 3:1 and inlet temperature 150 °C having the smallest log reduction (0.3 log cycles). All samples containing different WPI:GA ratios maintained sufficient viability (>7 log CFU/g) during the first three weeks of storage at 25 °C. These results could provide insights for further developing P. acidilactici as commercial probiotic products.

The Changes Occurring in Proteins during Processing and Storage of Fermented Meat Products and Their Regulation by Lactic Acid Bacteria

Protein, which is the main component of meat, is degraded and oxidized during meat fermentation. During fermentation, macromolecular proteins are degraded into small peptides and free amino acids, and oxidation leads to amino acid side chain modification, molecular crosslinking polymerization, and peptide chain cleavage. At different metabolic levels, these reactions may affect the protein structure and the color, tenderness, flavor, and edible value of fermented meat products. Lactic acid bacteria are currently a research hotspot for application in the fermented meat industry. Its growth metabolism and derivative metabolites formed during the fermentation of meat products regulate protein degradation and oxidation to a certain extent and improve product quality. Therefore, this paper mainly reviews the changes occurring in proteins in fermented meat products and their effects on the quality of the products. Referring to studies on the effects of lactic acid bacteria on protein degradation and oxidation from all over the world, this review aims to provide a relevant reference for improving the quality of fermented meat products.

Screening and identification of biogenic amine oxidase producing strains in Sanchuan Ham and their effect on biogenic amine accumulation

Sanchuan ham is a kind of popular fermented meat product in China. To understand the role of microorganisms in reducing the accumulation of Biogenic amine (BA) during ham fermentation. Biogenic amine oxidase-producing strains were screened and identified using color development method on double-layered plate, oxidase test, high-performance liquid chromatography (HPLC), physiological, biochemical methods, and 16 S rDNA. And then a model for simulated fermentation of Sanchuan ham was developed using the strains as single or mixed starter cultures. The results showed that two biogenic amine oxidase-producing strains were identified as Enterococcus faecium and Enterococcus faecalis from Sanchuan ham by compared to the NCBI database. And the mixed starter cultures showed a more remarkable effect on the decreased production of BA compared to single starter cultures, especially cadaverine and tyramine. The cadaverine was decreased from 92.74 ± 2.44 mg/Kg to 53.95 ± 2.69 mg/Kg and tyramine was decreased from 94.23 ± 3.42 mg/kg to 57.24 ± 3.51 mg/kg in mixed starter cultures than the control group. These results indicate exist biogenic amine oxidase-producing strains could decrease the accumulation of BA in Sanchuan ham. This study reveals important findings for improving the safety and health of Sanchuan ham and other fermented meat products.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-022-05419-y.

Effect of Biogenic Amine-Degrading Lactobacillus on the Biogenic Amines and Quality in Fermented Lamb Jerky

This study compares five types of lamb jerky, namely, CO (without starter culture), PL-4 (with producing putrescine, cadaverine, histamine, and tyramine), BL4-8 (degrading putrescine, cadaverine, histamine, and tyramine), CL4-3 (degrading putrescine and tyramine), and X3-2B (degrading histamine and tyramine). A study was performed to examine the effects of starter culture on the physical−chemical quality, flavor, and biogenic amines (BAs) during fermentation and ripening. At the end of fermentation, the pH value of the BL4-8 group (4.75) was significantly lower than that of other groups (p < 0.05). After high-temperature roasting, the water activity (0.55), water content (22.6%), nitrite residue (0.41 mg/kg), and TBARS value (0.27 mg/100 g) of the X3-2B group were significantly lower than those of other groups (p < 0.05). The findings show that adding starter BL4-8, CL4-3, and X3-2B can increase the variety and content of flavor in the product. The levels of histamine, putrescine, and tyramine were significantly lower in the BL4-8, CL4-3, and X3-2B groups than in CO and PL-4 groups. This study shows that BL4-8, CL4-3, and X3-2B are potential starters for fermented meat products.

Vaginal Dysbiotic Microbiome in Women With No Symptoms of Genital Infections

The vaginal microbiome plays a critical role in determining the progression of female genital tract infections; however, little is known about the vaginal microbiota of Indian women. We aimed to investigate the vaginal microbial architecture of women with asymptomatic bacterial vaginosis (BV) (n=20) and normal microbiota (n=19). Microbial diversity was analyzed in vaginal swabs from regularly menstruating women (18-45yrs) by 16S rRNA V3-V4 amplicon (MiSeq Illumina) sequencing. Rarefaction analysis showed a higher number of species in normal flora compared to BV. Alpha diversity as measured by Pielou’s evenness revealed microbial diversity was significantly greater in BV samples than normal microbiota (p= 0.0165). Beta diversity comparison using UniFrac metrics indicated distinct microbial communities clustering between normal and BV flora. Firmicutes were the major phyla observed in vaginal specimens of normal microbiota whereas Actinobacteria, Fusobacteria, Bacteroidetes were significantly abundant in BV samples. Notably, the relative abundance of Lactobacillus was significantly high in normal microbiota. Conversely Gardnerella, Sneathia, Prevotella, Atopobium, Ureaplasma, Dialister significantly dominated dysbiotic microbiota. Relative frequency of Lactobacillus decreased significantly in BV (6%) as compared to normal microbiota (35.2%). L. fermentum, L. gasseri, L. iners, L. jensenii, L. mucosae, L. ruminis, L. salivarius, L. coleohominis was more exclusively present in normal microbiota. L. iners was detected from both the groups with a relative frequency of 50.4% and 17.2% in normal and BV microbiota respectively. Lefse analysis indicated Atopobium vaginae, Sneathia amnii, Mycoplasma hominis Prevotella disiens in the vaginal microbiota as a biomarker for dysbiosis and L. jensenii as a biomarker of a healthy microbiota. Firmicutes were negatively correlated to Tenericutes, Actinobacteria, Bacteroidetes, and Fusobacteria. Proteobacteria positively correlated to Tenericutes, and Bacteroidetes were shown to be positively correlated to Fusobacteria. Predicted functional analysis indicated differences in the functional profiles between BV and normal microbiota. Normal microbiota utilized pathways essential for phosphatidylglycerol biosynthesis I & II, peptidoglycan biosynthesis, geranylgeranyl diphosphate biosynthesis I, mevalonate pathway, CoA biosynthesis pathway I and pyrimidine nucleotide salvage; whereas BV bacteria had characteristic aromatic amino acid biosynthesis, pentose phosphate pathway, carbohydrate degradation. In conclusion, women with asymptomatic BV have vaginal microbiota significantly different than women with normal microbiota. Furthermore, the study provides insights into the vaginal microbial structure of Indian women that will enable us to explore the prospective candidates for restoring the vaginal microbiota.

Anti-Obesity Efficacy of Pediococcus acidilactici MNL5 in Canorhabditis elegans Gut Model

In the present study, thirty two lactic acid bacteria (LAB) were isolated from fermented Indian herbal medicine. In comparison to other strains, MNL5 had stronger bile salt hydrolase (BSH) and cholesterol-lowering properties. Furthermore, it can withstand the extreme conditions found in the GI tract, due to, e.g., pepsin, bile salts, pancreatin, and acids. Pediococcus acidilactici MNL5 was identified as a probiotic candidate after sequencing the 16S rRNA gene. The antibacterial activity of P. acidilactici MNL5 cell-free supernatants (CFS) against Escherichia coli, Staphylococcus aureus, Helicobacter pylori, Bacillus cereus, and Candida albicans was moderate. A Caenorhabditis elegans experiment was also performed to assess the effectiveness of P. acidilactici MNL5 supplementation to increase life span compared to E. coli supplementation (DAF-2 and LIU1 models) (p < 0.05). An immense reduction of the lipid droplets of C. elegans was identified through a fluorescent microscope. The drastic alteration of the expression of fat genes is related to obesity phenotypes. Hence, several paths are evolutionary for C. elegans; the results of our work highlight the nematode as an important model for obesity.

Inoculation of Lactobacillus sakei on Quality Traits of Dry Fermented Sausages

In this study, fermented sausage prepared by inoculating different strains of Lactobacillus sakei was assessed for their physiochemical, microbiological, and textural characteristics during fermentation and ripening. Five treatments were prepared: Control (commercial starter culture, C), L. sakei Korean Collection for Type Cultures (KCTC)-3802 (S1), L. sakei KCTC-3598 (S2), L. sakei KCTC-5053 (S3), and L. sakei KCTC-3603 (S4). The different strains of L. sakei did not show substantial differences (P>0.05) in pH values for dry fermented sausages at the end of the ripening period. Water activity (aw) values for all treatments were below 0.85 (P<0.05). Total viable count at the end of the study decreased in all L. sakei starter culture inoculated fermented sausages as S3> S2> S1> S4. High values of lactic acid bacteria (LAB) count and hardness were observed in the S2 batch as compared to other L. sakei inoculated treatments at the end of ripening (21st day). S3 inoculated with L. sakei strain exhibited significantly (P<0.05) higher value of a* (redness). A significant difference (P<0.05) in thiobarbituric acid reactive substances was exhibited in the following order: S4> S2> S1> S3> C. This study suggests that inoculation of S3 (L. sakei KCTC-5053) strain can improve the red color and reduce lipid oxidation while S2 enhances better microbiological quality as LAB. Incorporation of S3 and S2 strains accordingly can be helpful to enhance the quality of dry fermented sausages.

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.

Dry Fermented Sausages with Total Replacement of Fat by Extra Virgin Olive Oil Emulsion and Indigenous Lactic Acid Bacteria

Research background

Formulations based on vegetable or fish oil and modifications in the production technology of dry fermented sausages have emerged in recent years aiming to achieve the desirable target of reducing the fat content of these meat products. However, previous efforts have confronted many difficulties, such as high mass loss and unacceptable appearance due to intensely wrinkled surfaces and case hardening. The objective of this study is to produce and evaluate dry fermented sausages by utilising a meat protein-olive oil emulsion as fat substitute and indigenous lactic acid bacteria (LAB) with probiotic properties isolated from traditional Greek meat products.

Experimental approach

A novel formulation with extra virgin olive oil and turkey protein was developed to totally replace the conventionally added pork fat. Probiotic and safety characteristics of autochthonous LAB isolates from spontaneously fermented sausages were evaluated and three LAB isolates were finally selected as starter cultures. Physicochemical, microbiological and sensory analyses were carried out in all treatments (control, Lactobacillus acidophilus, L. casei, L. sakei and Pediococcus pentosaceus) during fermentation.

Results and conclusions

Ready-to-eat sausages were found to be microbiologically stable. The olive oil-based formulation produced in this study generated a mosaic pattern visible in the sliced product simulating the fat in conventional fermented sausages and was regarded as an ideal fat substitute for the production of fermented sausages. An autochthonous isolate of Lactobacillus casei adapted the best to the final products as it was molecularly identified to be present in the highest counts among the LAB isolates used as starter cultures.

Novelty and scientific contribution

Α novel and high-quality dry fermented meat product was produced by replacing the added pork fat with a fat substitute based on a meat protein-olive oil emulsion. Autochthonous LAB with in vitro probiotic properties could have a potential use in large-scale novel dry fermented sausage production. Such isolates could be used as starters in an effort to standardise the production process and retain the typical organoleptic and sensory characteristics. Moreover, isolates like L. casei 62 that survived in high counts in the final products can increase the safety of fermented sausages by competing not only with pathogens but also with the indigenous microbiota and could have a potential functional value for the consumer.

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.

Rice flour powder carrying mixed starter culture of Lactiplantibacillus plantarum KU-LM173 and Pediococcus acidilactici KU-LM145 for fermented mussel, Perna viridis Linnaeus 1758

AIMS

To develop a dried rice flour powder (DP) formulation to contain a lactic acid bacterial starter culture for fermenting mussel meat (FM).

METHODS AND RESULTS

Lactiplantibacillus plantarum KU-LM173 (LP), Enterococcus hirae KU-LM174 and Pediococcus acidilactici KU-LM145 (PA) were selected from commercial FMs and identified to have high acid and protease production. Mixed culture between LP, for high acid production, and PA, for the flavour, was the best for DP and had greater organoleptic properties than a single starter fermentation. The best ratio of DP for production was 1% of the mussel weight, while the highest numeric scoring of the organoleptic test between 3% and 6%. The starter culture fermentation accelerated over the natural (wild) fermentation and ended at day 3. The shelf life of the product was at least 30 days at 30-35°C with no pathogens detected. The shelf life of DP at 4°C was 10 weeks.

CONCLUSIONS

DP with the best strains and long shelf life promoted safety of FM and reduced the processing time. High consumer acceptance, protease and acid production and flavour were unique product characteristics.

SIGNIFICANCE AND IMPACT OF STUDY

Accelerated commercial FMs with effective DP formulation for the industrial sector may be plausible.

The Use of the Mixed Bacteria Limosilactobacillus fermentum and Staphylococcus carnosus in the Meat Curing Process with a Reduced Amount of Sodium Nitrite

The aim of the research was to estimate the possibility of using mixed bacteria cultures consisting of Lactobacillus fermentum S8 and Staphylococcus carnosus ATCC 51365 in the meat curing process with a reduced amount of sodium nitrite and to study the effect of bacteria on residual nitrites and nitrates, nitrosyl pigments content, colour, pH, redox potential, microbiologic, and the sensory quality of a cooked meat product. The study was performed on heat treated three-model meat treatments in cans: (C) a control treatment with NaNO2 at 100 mg/kg, (M) a treatment with NaNO2 at 50 mg/kg and (SL) a treatment with NaNO2 at 50 mg/kg and L. fermentum S8 at about 107 cfu/g and S. carnosus ATCC 51365 at about of 107 cfu/g. The research was performed after production and after cold storage. It was shown that using a mixed bacteria culture for meat curing had an influence (p < 0.05) on reducing nitrite and nitrate levels and increasing the amount of nitrosyl pigments in the SL treatment compared to the M treatment. Applying mixed bacteria in curing meat with NaNO2 at 50 mg/kg allowed for obtaining a higher redness in the cooked meat product after production, storage and exposure to light than in the product cured with NaNO2 at 100 mg/kg, with similar sensory and microbiological quality in both products.

Autochthonous Probiotics in Meat Products: Selection, Identification, and Their Use as Starter Culture

The increasing demand for functional food is pushing the food industry to innovate the conventional and well-known foods. Producing functional foods, especially with probiotics in meat products, is an intricate and multistage task that involves: the selection of microorganisms with probiotic potential, the identification at strain level, and the evaluation of probiotic strains in the processing of meat products. The resistance to digestion, followed by the successful colonization in the small intestine and the safety are the main criteria used to select and identify (at strain level) a probiotic, as reported in recent studies about the autochthonous microbiota of meat products. Further insertion (as starter culture) in a meat system for fermentation is the simplest approach to obtain a probiotic meat product. Among the innumerous microorganisms naturally found in meat products, lactic acid bacteria (LAB) play a central role by fitting in both probiotic and meat products processing criteria.

Application of Weissella cibaria X31 or Weissella confusa L2 as a starter in low nitrite dry-fermented sausages

Effects of Weissella strains (Weissella cibaria X31 or Weissella confusa L2) as starters on the physicochemical, volatile, proteolytic, microbiological, and sensory properties of low-nitrite dry-fermented sausages were evaluated for 20 d. Results showed that the addition of 8 log CFU/g of Weissella strains increased the redness, hardness, adhesiveness, and chewiness, but decreased the pH, water activity, and nitrite content of sausages during processing. Morover, Weissella strains inhibited the growth of Salmonella enterica. Weissella strains also could hydrolyze myofibrillar proteins in sausages. The sausage inoculated with W. confusa L2 was more abundant in ester compared with the control. Sausages inoculated with W. cibaria X31 and W. confusa L2 and sodium nitrite (0.05 g) had more desirable characteristics, compared with other groups. W. cibaria X31 and W. confusa L2 show potential as multifunctional starters in low-nitrite fermented sausage, which is uniqueness and addressed the gap of Weissella in low nitrite sausages. This study is distinct in that Weissella strains were found to improve the redness of dry-fermented sausages and was effective at partly replacing nitrite in dry-fermented sausages, addressing the research gap regarding the application of Weissella in low-nitrite sausages.

Applicability of potentially probiotic Lactobacillus casei in low-fat Italian type salami with added fructooligosaccharides: in vitro screening and technological evaluation

The aim was to evaluate the use of Lactobacillus casei strains in the fermentation process of low-fat Italian type salami with fructooligosaccharides (FOS). A screening using probiotic strains was performed at pH 5.5, 5.0 and 4.5 and incubation temperatures of 15 and 25 °C. Lactobacillus casei SJRP66 and Lactobacillus casei SJRP169 were selected and added to the low-fat fermented sausage - C (control), FOS (25% reduced fat with 2% FOS), FOS_66 (25% reduced fat with 2% FOS and L.casei SJRP 66) and FOS_169 (25% reduced fat with 2% FOS and L.casei SJRP 169). The evaluation included pH, moisture, lactic acid bacteria count, probiotic count, weight loss, instrumental color, TBARS and texture parameters. FOS_66 and FOS_169 presented a good probiotic count (8 log CFU/g) and similar technological behavior to the control. The addition of the probiotic showed no effect on lipid oxidation and * value. These strains of probiotic showed promising properties for applications in low-fat Italian type salami with healthier appeal.

Technological Characterisation of Probiotic Lactic Acid Bacteria as Starter Cultures for Dry Fermented Sausages

The objective of this study was to investigate probiotic microorganisms for use as starter cultures in dry fermented sausages production. A total of eight strains were studied evaluating technological and safety characteristics including the ability to grow, lactic acid production, gas formation, catalase activity, nitrate reductase activity, proteolytic activity, lipolytic activity, hydrogen peroxide production, salt tolerance, performance at low temperatures, decarboxylation of amino acids and antimicrobial activity against pathogens associated with the product. Lactobacillus rhamnosus R0011, L. rhamnosus Lr-32, Lactobacillus paracasei Lpc-37, Lactobacillus casei Shirota and Enterococcus faecium MXVK29 were good candidates for use as fermented sausages starters cultures because they showed the best technological and safety properties since they did not demonstrate amino acid decarboxylation but showed antimicrobial activity against Listeria monocytogenes, Escherichia coli, Salmonella Dublin and Staphylococcus aureus. L. rhamnosus Lr-32 was the strain best tolerating the levels of salt, nitrate and low pH during the simulated stages of fermentation and ripening of sausage. The strain was thus the most promising of the tested probiotics as sausage starter culture. The findings warrant studies in a meat matrix, such as that of raw-cured sausage, to evaluate the effects of L. rhamnosus Lr-32 under actual conditions.

Review on Non-Dairy Probiotics and Their Use in Non-Dairy Based Products

Consumer demands for foods promoting health while preventing diseases have led to development of functional foods that contain probiotic bacteria. Fermented dairy products are good substrates for probiotic delivery, but the large number of lactose intolerant people, their high fat and cholesterol content and also due to the growing vegetarianism the consumers are seeking for alternatives. Therefore, researches have been widely studied the feasibility of probiotic bacteria in non-dairy products such as fruits, vegetables, and cereals. This review describes the application of probiotic cultures in non-dairy food products.

Utilization of Grape Seed Extract as a Natural Antioxidant in the Technology of Meat Products Inoculated with a Probiotic Strain of LAB

Grape seeds have been evaluated for use as food ingredients with stabilizing effects in meat technology. A pork neck, inoculated with probiotic monoculture (Lactobacillus rhamnosus LOCK900), was used as the matrix. The study compared the antioxidant potential of grape seed extract to sodium ascorbate. Three experimental variants of the products were prepared: With grape seed extract, with sodium ascorbate, and without additives. The meat ripened for two months, and during this period of time biophysicochemical analyses (product color, pH, number of lactic acid bacteria, content of free fatty acids, and thiobarbituric acid reactive substances) were carried out. It was found that the extract inhibited lipid hydrolysis occurring in the neck (1% of oleic acid) and limited oxidative processes (0.46 mg MDA kg-1), with efficacy similar to that of sodium ascorbate (0.9% of oleic acid and 0.53 mg MDA kg-1, respectively). No limitation of the desired lactic acid bacteria growth (approximately 7 log cfu g-1) was noticed in the meat samples with the extract. The results are optimistic because they indicate that not only is it possible to produce fermented pork neck inoculated with probiotic, but there are also no obstacles to utilizing grape seed extract as a natural antioxidant in this technology.

Construction of a shuttle expression vector for lactic acid bacteria

Background

Lactic acid bacteria (LAB) are a diverse group of Gram-positive bacteria, which are widely distributed in various diverse natural habitats. These are used in a variety of industrial food fermentations and carry numerous traits with utmost relevance to the food industry. Genetic engineering has emerged as an effective means to improve and enhance the potential of commercially important bacterial strains. However, the biosafety of recombinant systems is an important concern during the implementation of such technologies on an industrial scale. In order to overcome this issue, cloning and expression systems have been developed preferably from fully characterized and annotated LAB plasmids encoding genes with known functions.

Results

The developed shuttle vector pPBT-GFP contains two theta-type replicons with a copy number of 4.4 and 2.8 in Pediococcus acidilactici MTCC 5101 and Lactobacillus brevis MTCC 1750, respectively. Antimicrobial “pediocin” produced by P. acidilactici MTCC 5101 and green fluorescent protein (GFP) of Aequorea victoria were successfully expressed as selectable markers. Heterologous bile salt hydrolase (BSH) from Lactobacillus fermentum NCDO 394 has been efficiently expressed in the host strains showing high specific activity of 126.12 ± 10.62 in P. acidilactici MTCC 5101 and 95.43 ± 4.26 in the case of L. brevis MTCC 1750, towards glycine-conjugated bile salts preferably as compared to taurine-conjugated salts.

Conclusion

The present article details the development of a LAB/LAB shuttle expression vector pPBT-GFP, capable of replication in LAB hosts, P. acidilactici MTCC 5101, and L. brevis MTCC 1750. Pediocin and GFP have been used as selectable markers with the efficient production of heterologous extracellular bile salt hydrolase. Thus, the constructed vector pPBT-GFP, with its ability to replicate in multiple hosts, low copy number, and stability in host cells, may serve as an ideal tool for improving LAB strains of commercial value using genetic engineering.

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.

Unraveling microbial community diversity and succession of Chinese Sichuan sausages during spontaneous fermentation by high-throughput sequencing

The microbial community diversity and succession of Chinese Sichuan sausages during the spontaneous fermentation were demonstrated using high-throughput sequencing technology. The bacterial diversity was abundant and the succession of bacterial community along the direction of Lactobacillus spp. increased and Weissella spp. decreased. While fungal diversity was single and trace fungal population was detected. The core functional microbiota were lactic acid bacteria, including Lactobacillus spp., Weissella spp. and Pediococcus spp. In initial fermentation, Weissella spp. was the dominant bacteria and its relative abundance was 49.84%, but then its relative abundance decreased to 11.96% during fermentation before recovering to 26.74% at the end of fermentation. Meanwhile, Lactobacillus spp. rose from 24.70 to 55.74% and became the dominant genus. Moreover, Pediococcus spp. increased from 0.06 to 18.05% on day 20 but then decreased to 1.89% on day 30. These results revealed that the primary microorganisms contributing to spontaneous fermentation of Chinese Sichuan sausages were bacteria, while eukaryotic microorganisms such as yeast scarcely contributed to fermentation.

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.

Effect of starter culture on microbiological, physiochemical and nutrition quality of Xiangxi sausage

Fermented sausages have a long tradition originating from China. In this study, three starter microorganisms including Pediococcus pentosaceus (P), Staphylococcus xylosus (S), and a combination of P. pentosaceus and S. xylosus (P + S) were conducted for the manufacture of traditional Xiangxi (a city in China) fermented sausages. The physicochemical changes of the above three kinds of sausages during fermentation were studied and discussed, and also compared with these properties on the natural fermented sausage (N, i.e., control). The results revealed that five kinds of bacterial phases were existed at different fermentation stages in N, P, S and P + S fermented sausages, respectively. The microbiological data showed that an initial enterobacteria count of approximately 5.3 log CFU/g for all four batches of sausages. The enterobacteria count in the inoculated sausages of P and P + S groups decreased significantly to about 1 log CFU/g whereas group N and S had a count of about 3.3 log CFU/g after fermentation. In the early stages of fermentation, the pH rapidly decreased below 5.3. FAA and FFA were significantly increased in all groups and TBARS value in group P was higher than that of the other three groups. In conclusion, starter cultures can be used to improve the hygiene level of Xiangxi sausages without significant effects on pH, A_W, and nitrite residue.