发酵香肠益生型乳酸菌发酵剂的筛选

从主要自然发酵肉制品中分离、纯化得到77株耐酸耐胆汁的乳酸菌,并进一步对分离菌株进行了耐高酸(pH2.5)、0.3%胆盐的生长实验.25株在pH值2.5,培养3 h后表现出较高存活性,21株经低酸预处理后在0.3%胆盐存在的情况下生长良好.最后运用API 50CHL对筛选菌株进行了鉴定.这些菌株可作为进一步筛选发酵香肠优良乳酸菌种的出发菌株,以便筛选品质优良的益生性乳酸菌,作为新型发酵香肠发酵剂.     

Competitiveness and antibacterial potential of bacteriocin-producing starter cultures in different types of fermented sausages

Application of bacteriocin-producing starter cultures of lactic acid bacteria in fermented sausage production contributes to food safety. This is sometimes hampered by limited efficacy in situ and by uncertainty about strain dependency and universal applicability for different sausage types. In the present study, a promising antilisterial-bacteriocin producer, Lactobacillus sakei CTC 494, was applied as a coculture in addition to commercial fermentative starters in different types of dry-fermented sausages. The strain was successful in both Belgian-type sausage and Italian salami that were artificially contaminated with about 3.5 log CFU g(-1) of Listeria monocytogenes. After completion of the production process, this led to listerial reductions of up to 1.4 and 0.6 log CFU g(-1), respectively. In a control sausage, containing only the commercial fermentative starter, the reduction was limited to 0.8 log CFU g(-1) for the Belgian-type recipe, where pH decreased from 5.9 to 4.9, whereas an increase of 0.2 log CFU g(-1) was observed for Italian salami, in which the pH rose from 5.7 to 5.9 after an initial decrease to pH 5.3. In a Cacciatore recipe inoculated with 5.5 log CFU g(-1) of L. monocytogenes and in the presence of L. sakei CTC 494, there was a listerial reduction of 1.8 log CFU g(-1) at the end of the production process. This was superior to the effect obtained with the control sausage (0.8 log CFU g(-1)). Two commercial antilisterial cultures yielded reductions of 1.2 and 1.5 log CFU g(-1). Moreover, repetitive DNA sequence-based PCR fingerprinting demonstrated the competitive superiority of L. sakei CTC 494.     

Flavour profiles of dry sausages fermented by selected novel meat starter cultures

Probiotic or bioprotective Lactobacillus rhamnosus strains GG, LC-705 and E-97800 as well as Pediococcus pentosaceus E-90390 and Lactobacillus plantarum E-98098 were studied for their ability to act as main fermenting organisms in the manufacturing process of dry sausages. In the preliminary tests, their abilities to produce lactic acid and biogenic amines, histamine or tyramine, were studied in MRS broth and analysed by high-performance liquid chromatography. The strains produced higher or equal amounts of lactic acid compared to control and were amine negative. During the actual fermentation process of dry sausages the numbers of inoculated bacteria increased from the level 6.5-7.0 log cfu/g to 8.0-9.0 log cfu/g. The most fast growing strains were P. pentosaceus E-90390 and the control while the growth of L. plantarum E-98098 and L. rhamnosus LC-705 were the slowest. The pH value of the sausages decreased from 5.6 to 4.9-5.0. The presence of these experimental strains as major organisms in the sausages after fermentation and ripening was confirmed on the bases of their genetic fingerprints. The flavour profiles of the experimental sausages produced by these probiotic or protective strains were similar with that produced by the commercial meat starter culture and commercial North European dry sausage recipe.     

发酵香肠中葡萄球菌发酵剂的筛选

筛选、鉴定和表征在不同发酵香肠中出现的凝固酶阴性葡萄球菌,通过测定所筛选菌的蛋白质水解能力、脂肪水解能力、在胆汁中存活能力、对抗生素敏感性和产细菌素实验,筛选出具有优势的发酵剂.     

Mixed starter cultures to control biogenic amine production in dry fermented sausages

Several combinations of an amine-negative Lactobacillus sakei strain, along with proteolytic Staphylococcus carnosus or Staphylococcus xylosus strains, were used to study the influence of mixed starter cultures on biogenic amine production during the manufacture of dry fermented sausages. Changes in pH, water content, proteolysis, microbial counts, and biogenic amine contents were simultaneously examined in a spontaneously fermented batch and in three mixed starter-mediated batches. A double-controlled microbial charge initially inoculated as mixed starter culture of L. sakei and Staphylococcus spp. (all amine-negative strains) drastically reduced tyramine, cadaverine, and putrescine accumulation. No production of other aromatic amines such as histamine, phenylethylamine, or tryptamine was observed in any batch. The polyamines, spermine and spermidine, were found in raw materials and their levels decreased slightly in the spontaneously fermented batch. No correlation between proteolysis and biogenic amine production was observed. The use of proper technological conditions favoring starter development and the use of the raw materials with good hygienic quality make it possible to produce fermented sausages nearly free of biogenic amines.     

The use of commercial starter cultures in the production of Turkish semi-dry fermented sausages

 The effects of three different starter cultures (Pediococcus acidilactici, Staphylococcus xylosus plus P. pentosaceus, S. carnosus plus Lactobacillus pentosus) were evaluated during the production of Turkish semi-dry fermented sausages. Sausages were studied during the fermentation phase, after heat processing and after drying for 24 h and 72 h. Chemical and organoleptical results indicated that in the processing of these semi-dry sausages a starter culture of P. acidilactici should be used. The use of this culture significantly reduced the pH, increased the lactic acid content and percentage of total heme pigments converted to the cured pigment and improved the development of the sausages' characteristics, i.e. color, appearance, flavor and general acceptability. Received: 20 February 1998 / Revised version: 7 May 1998     

The effect of starter cultures on proteolytic changes and amino acid content in fermented sausages

The main objective of this work was to examine the effects of using five types of commercial starter cultures in fermented sausages. During the fermentation stage, changes in proteolytic characteristics were observed in fermented sausages. Proteolytic activity was high in Ls_b + Sc:(Lactobacillus sakei + Staphylococcus carnosus) and Pp + Sx:(Pediococcus pentosaceus + Staphylococcus xylosus) starter-inoculated sausages during processing. Moreover, a slight increase in proteolytic activity was detected during storage in both these sausages. Sarcoplasmic and myofibrillar proteins were also affected by this starter culture addition, during the fermentation, ripening and intense proteolysis were observed in both the fermented sausages. The content of free amino acids was similar at the beginning of the fermentation stage for all the studied batches. However, the high differences in the content of free amino acids at the end of the process could be attributed to the starter culture activity.     

Effect of selected autochthonous starter cultures on processing and quality characteristics of Greek fermented sausages

Selected autochthonous starter (SAS) cultures (i.e. Lactobacillus sakei 8416, Lactobacillus sakei 4413, and L. sakei 8426, L. plantarum 7423 and L. curvatus 8427) were used as starter cultures in addition to a control treatment in the production of fermented sausages. The SAS cultures had a rapid growth and dominated the fortuitous population of LAB during the whole fermentation and ripening process improving the sensory attributes in comparison to control. Apart from the treatment produced with L. sakei 8416, all other SAS cultures prevented the lipid oxidation to values lower than 1 mg malonaldehyde/kg. The Micrococcaceae count and the redness of the sausages was not affected by the smoking and the acidification during the fermentation in the treatments produced with L. sakei 8416 and L. sakei 4413. The treatment of L. sakei 4413 had the lowest (*P < 0.05) content of all biogenic amines. In comparison to the control, the reduction of tyramine was 13%, tryptamine 55%, cadaverine 60% and putrescine 72%. Sausages produced with SAS cultures L. sakei 4413 and L. sakei 8416 had the highest scores for all sensory attributes. The results indicated that the SAS culture of L. sakei 4413 is the best autochthonous starter culture for fermented sausages.     

Utilisation possibility of Enterococcus faecalis isolates from neonate's faeces for production of fermented sausages as starter cultures

This study aimed at assessing the utilisation possibility of Enterococcus faecalis as starter cultures for production of fermented sausages. The E. faecalis isolates isolated from faeces samples of 5‐day‐old healthy newborn babies, identified by 16SrDNA sequencing and free from virulence determinants as proven by genomic sequencing, were used for fermented sausages production as starter culture. Six treatments (four inoculated with four different E. faecalis isolates, one with commercial starter culture and one control) were prepared. The inoculation with E. faecalis showed a stronger acidification compared with the control. The treatments with E. faecalis showed significantly higher flavour and acceptability scores in comparison with the control or commercial starter culture. Both of commercial starter culture and E. faecalis were positive with tyramine. Apart from the amine production, the inoculation with E. faecalis generally improved the acidifying activity and flavour of the products, suggesting their application potentials in fermented sausages production as starter cultures.     

Screening of lactic acid bacteria and bifidobacteria for potential probiotic use in Iberian dry fermented sausages

The purpose of this study was to select lactic acid bacteria and bifibobacteria strains as potential probiotic cultures during the processing of Iberian dry fermented sausages. A total of 1000 strains were isolated from Iberian dry fermented sausages (363), and human (337) and pig faeces (300) in different culture media. Around 30% of these strains, mainly isolated from Iberian dry fermented sausages in LAMVAB agar, were pre-selected for testing as potential probiotics by their ability to grow adequately at the pH values and NaCl concentrations of these meat products during the ripening process. Of the in vitro investigations used to predict the survival of a strain in conditions present in the gastro intestinal tract, exposure to pH 2.5 showed itself to be a highly discriminating factor with only 51 out of 312 pre-selected strains resisting adequately after 1.5h of exposure. All acid-resistant isolates identified as lactobacilli originated from human faeces (Lactobacillus casei and Lactobacillus fermentum) and pig faeces (Lactobacillus reuteri, Lactobacillus animalis, Lactobacillus murinus, and Lactobacillus vaginalis). Pediococcus acidilactici strains were isolated from Iberian dry fermented sausages and pig faeces, whereas the greatest number of Enterococcus strains were identified as Enterococcus faecium, with this species being isolated from Iberian dry fermented sausages, and human and pig faeces. Most of these strains are promising probiotic meat culture candidates suitable for Iberian dry fermented sausages.     

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

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

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

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

Influence of starter cultures on the generation of antioxidant nitrogen compounds in Iberian dry‐fermented sausages

The purpose of this work was to investigate the influence of a starter culture on the generation of nitrogen compounds with antioxidant activity during the ripening of Iberian dry‐fermented sausages. Starters P200S34 (P. acidilactici M200 and S. vitulus RS34) and P198S34 (P. acidilactici MS198 and S. vitulus RS34) were used to make the Iberian dry‐fermented sausages ‘salchichón’ and chorizo; then, the physicochemical and microbial properties were determined during the ripening process. The oxygen radical absorbance capacity (ORAC) assay was employed to evaluate the antioxidant potential of the nitrogen extracts obtained during ripening of the sausages. This activity was correlated with the most relevant compounds detected by HPLC‐ESI‐MS in the final ripened extracts. Although a relevant part of the antioxidant activity was attributed to the predominant natural nitrogen fraction, the microbial population found in fermented sausages and the fermentation conditions significantly influenced the low molecular weight nitrogen profile and antioxidant activities. Inoculation with the starter culture P200S34 increased free amino acids and amines, such as methionine and tyramine, but other nitrogen compounds also increased the antioxidant activity of the low molecular weight nitrogen extracts. Thus, these starter cultures in Iberian sausages can contribute to delaying oxidative changes during storage.     

Characterization of fermented silver carp sausages inoculated with mixed starter culture

To improve the characteristics and functionality, and increase the use of fish muscle, three groups mixed starter cultures (group one: Lactobacillus plantarum-15, Staphylococcus xylosus-12 and Pediococcus pentosaceus-ATCC33316 [S-PXP]; group two: Lactobacillus planatrum-15, Staphylococcus xylosus-12 and Lactobacillus casei subs casei-1.001 [S-PXC]; and group three: Staphylococcus xylosus-12, Lactobacillus casei subsp. casei-1.001 and P. pentosaceus-ATCC33316 [S-XCP]) were inoculated in minced silver carp muscle to produce a fermented fish product. During the 48 h fermentation at 30 °C, silver carp muscle inoculated with mixed starter cultures resulted in a rapid pH decrease, suppression in the increase of thiobarturic acid (TBARS) values, total volatile base nitrogen (TVB-N), trimethylamine (TMA), and the growth of spoilage bacteria and pathogens, and had higher whiteness than the control (without any starter) (P<0.05). The changes in SDS-PAGE indicated extensive hydrolysis of muscle protein occurred during fermentation. This study showed that the mixed starter cultures could substantially improve the flavor, digestibility, and nutritional value of the silver carp muscle.     

营养生物发酵剂在乳品中的应用

<正> 乳品经发酵变酸后,便具有更强的防腐能力,保质期更长。在发酵乳的生产中,一般都是采用乳酸菌进行发酵。经研究发现,有些乳酸菌能促进人体健康,这就是所谓的营养乳酸菌(probiotic lactic acid bacteria)。随着人们生活的富足,对加工食品的要求除了用以充饥外,更要求具有保健功能。富含营养乳酸菌的营养生物发酵剂除了能在任何发酵乳制品中引发发酵过程外,还能增加发酵乳已有的营养价值作用,其发展潜力非常广阔。     

The effect of different starter cultures and ripening temperatures on formation of biogenic amine in Turkish fermented sausages

Different starter culture added groups (Group I: Lactobacillus sake, Staphylococcus xylosus; Group II: Lactobacillus plantarum, Staphylococcus carnosus; Group III: Lactobacillus curvatus, Staphylococcus carnosus, and Staphylococcus xylosus) and control group sausage samples were produced experimentally at two different temperatures (22 and 26 °C). In raw materials and all groups, by the 0th, 2nd, 5th and 7th days of the ripening period, the analysis of HPLC and biogenic amine (tyramine, histamine, cadaverine, putrescine, phenylethylamine, tryptamine, spermine, and spermidine) amounts, microbiological (Lactic acid bacteria, Micrococcus/Staphylococcus, Enterobacteriaceae, Enterococcus spp., and moulds–yeasts) and chemical (pH, dry matter, and salt) have been done. During the ripening period, there is no statistical discrepancy (P > 0.05) in terms of biogenic amine amounts, microbiological, and chemical values detected from the sausage samples produced at 26 and 22 °C. However, in both levels of temperature, there is statistical discrepancy (P < 0.001) detected in terms of tyramine, putrescine values and the count of Enterococcus spp. between the starter culture added samples and control group samples. By this study, it has been stated that the ripening temperature does not make any statistical discrepancy (P > 0.05) for all values but the use of starter culture prevents the formation of biogenic amine in Turkish fermented sausages.     

Rheology and sensory profiling of set-type fermented milks made with different commercial probiotic and yoghurt starter cultures

Varieties of set-type probiotic fermented milks and yoghurt were made from recombined skimmed milk powder, anhydrous milk fat and commercial starter cultures (direct-to-vat inoculation, DVI). Serum separation of fermented milks and yoghurt with high initial rates of syneresis proceeded more slowly than separation of those with low initial rates of syneresis; the decrease during the storage period was linear and the rate of decrease was dependent on the type of starter culture used. The firmness of these products increased over the time period, and the rate of increase was linear and independent of the starter culture. The production of exopolysaccharide material by the starter microflora also influenced syneresis and firmness of the probiotic fermented milks. The average profiles of organic acids of all the products were similar with the exception of two starter cultures that generated the highest level of acetic acid. After cross-validation, classification of the starter type using the organic acids values correctly predicted the type of starter culture used for 23 out of 24 samples. All the sensory attributes were influenced by the type of starter culture used and the trial, with the exception of viscosity character; acetic acid production by the microbial species of the starter cultures had the greatest influence on the flavour attribute.     

微生物发酵剂对发酵香肠中挥发性成分的影响

采用固相微萃取技术结合GC/MS,以壬烷作内标进行定性和半定量,分析自然发酵和添加发酵剂生产的两组发酵香肠的挥发性成分,共鉴定出39种挥发性成分。其中自然发酵组鉴定出35种,总含量为9.486μg等量壬烷/g发酵香肠;添加发酵剂组鉴定出32种,总含量为18.313μg等量壬烷/g发酵香肠。自然发酵香肠主要挥发性成分由萜烯类(27.71%)、酸类(26.42%)和酯类(25.32%)组成;在添加发酵剂组中,最重要的组成是酯类(42.10%),其次为酸类(26.52%)和萜烯类(18.07%)。     

Characterization of certain bacterial strains for potential use as starter or probiotic cultures in dairy products

The present work was aimed at characterizing 12 strains of lactic acid bacteria (LAB) to obtain improved potential starter or probiotic cultures that could be used for making dairy products from ewe's milk and cow's milk. Eight strains with antimicrobial properties, isolated from ewe's milk and from cheese made from ewe's and/or cow's milk, were studied. They were identified as Enterococcus faecalis (five strains), Lactococcus lactis subsp. cremoris, Leuconostoc mesenteroides, and Lactobacillus paracasei subsp. paracasei (one strain of each species). Additionally, four strains were obtained from the American Type Culture Collection: Lactobacillus casei 393 (isolated from cheese), L. lactis subsp. lactis 11454 (origin nonspecified and a producer of nisin), and two strains isolated from human feces (L. paracasei subsp. paracasei 27092 and Lactobacillus rhamnosus 53103, antibacterial agent producer). All E. faecalis strains showed at least one virulence factor (either hemolysin or gelatinase), which emphasizes the importance of these studies in this species. Both L. lactis strains and most Lactobacillus spp. were good acidifiers in ewe's milk and cow's milk at 30°C. High β-galactosidase activity, as well as aminopeptidase activities that favor the development of desirable flavors in cheese, were detected in all Lactobacillus spp. strains. Furthermore, L. rhamnosus ATCC 53103 showed α-fucosidase activity (thought to help colonization of the intestine) and lack of α-glucosidase activity (a trait considered positive for diabetic and obese humans). This last enzymatic activity was also lacking in L. lactis ATCC 11454. L. mesenteroides was the only strain D(2)-lactic acid producer. The selection of any particular strain for probiotic or dairy cultures should be performed according to the technological and/or functional abilities needed.     

Potential probiotic Lactobacillus strains from fermented sausages: Further investigations on their probiotic properties

A rational selection of probiotic microorganisms is an important challenge and requires the definition of fundamental information about the physiology and genetics of candidate strains. In this study, selected Lactobacillus (Lact.) strains already characterized in a previous study for their capability to resist low pH and to grow in conditions simulating the intestinal environment, were further investigated to explore their probiotic properties, such as the adhesion capability to intestinal human Caco-2 cell lines and their growth behaviour in the presence of various prebiotic carbohydrates. At first 25 Lactobacillus strains were characterized by pulsed field gel electrophoresis using the endonuclease NotI. Among them, 13 strains belonging to the Lact. plantarum-group were identified at species level by a multiplex PCR assay. Subsequently 11 Lactobacillus strains showing different PFGE restriction pattern and the best acid- and bile-resistances, were chosen to investigate their in vitro adhesion capability to human intestinal epithelial cells and their fermentation properties of five prebiotic substances (FOS, Inulin, IMO, GOS and lactulose) at a concentration of 2%. The 11 strains analysed in this study possessed good adhesion capability to Caco-2 cell layers and, in particular, the eight strains belonging to the Lact. plantarum-group showed the higher final number of viable adhering cells. Moreover a species-related fermentative behaviour was pointed out and the strain Lact. paracasei EL7 was the only one able to grow in the presence of all prebiotics tested. In conclusion the strains of Lactobacillus studied in this research could be further investigated to assess possible in vivo human health benefits.