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1.
This study was conducted to investigate the distribution and genetic diversity of the native lactic acid bacteria (LAB) population in nem chua, a popular traditional Vietnamese uncooked fermented sausage. A total of 74 LAB isolates were identified and their molecular fingerprints were obtained using repetitive-PCR (rep-PCR) and pulse-field gel electrophoresis (PFGE). The results revealed that the majority of LAB isolates were Lactobacillus plantarum (67.6%), followed by Pediococcus pentosaceus (21.6%). A minority of LAB (9.5%) were Lactobacillus brevis and Lactobacillus farciminis (1.4%). A large genetic plasticity within the same species was also observed. Both rep-PCR and PFGE methods were found to be acceptable regarding reproducibility and reliability. However, this study demonstrated the higher discriminatory power of PFGE compared to rep-PCR, as observed by the higher number of clusters generated (17 and 12 clusters of L. plantarum respectively, seven and six clusters of P. pentosaceus respectively and four and two clusters of L. brevis respectively), and lower percentage of similarity among clusters in PFGE data analysis. These results also revealed that there was not a single LAB strain that was found to predominate in the product. To our knowledge, this is the first detailed analysis of the native LAB population in nem chua. As this traditional sausage is fermented naturally or only with back-slop, knowledge about the native LAB population in the product is very important to understand the microflora that has been active in fermenting the nem chua and to ensure the safety of this uncooked sausage.  相似文献   

2.
Fu-tsai and suan-tsai are spontaneously fermented mustard products traditionally prepared by the Hakka tribe of Taiwan. We chose 5 different processing stages of these products for analysis of the microbial community of lactic acid bacteria (LAB) by 16S rRNA gene sequencing. From 500 LAB isolates we identified 119 representative strains belonging to 5 genera and 18 species, including Enterococcus (1 species), Lactobacillus (11 species), Leuconostoc (3 species), Pediococcus (1 species), and Weissella (2 species). The LAB composition of mustard fermented for 3 days, known as the Mu sample, was the most diverse, with 11 different LAB species being isolated. We used sequence analysis of the 16S rRNA gene to identify the LAB strains and analysis of the dnaA, pheS, and rpoA genes to identify 13 LAB strains for which identification by 16S rRNA gene sequences was not possible. These 13 strains were found to belong to 5 validated known species: Lactobacillus farciminis, Leuconostoc mesenteroides, Leuconostoc pseudomesenteroides, Weissella cibaria, and Weissella paramesenteroides, and 5 possibly novel Lactobacillus species. These results revealed that there is a high level of diversity in LAB at the different stages of fermentation in the production of suan-tsai and fu-tsai.  相似文献   

3.
The present study aims to evaluate the probiotic potential of lactic acid bacteria (LAB) isolated from naturally fermented olives and select candidates to be used as probiotic starters for the improvement of the traditional fermentation process and the production of newly added value functional foods. Seventy one (71) lactic acid bacterial strains (17 Leuconostoc mesenteroides, 1 Ln. pseudomesenteroides, 13 Lactobacillus plantarum, 37 Lb. pentosus, 1 Lb. paraplantarum, and 2 Lb. paracasei subsp. paracasei) isolated from table olives were screened for their probiotic potential. Lb. rhamnosus GG and Lb. casei Shirota were used as reference strains. The in vitro tests included survival in simulated gastrointestinal tract conditions, antimicrobial activity (against Listeria monocytogenes, Salmonella Enteritidis, Escherichia coli O157:H7), Caco-2 surface adhesion, resistance to 9 antibiotics and haemolytic activity. Three (3) Lb. pentosus, 4 Lb. plantarum and 2 Lb. paracasei subsp. paracasei strains demonstrated the highest final population (>8 log cfu/ml) after 3 h of exposure at low pH. The majority of the tested strains were resistant to bile salts even after 4 h of exposure, while 5 Lb. plantarum and 7 Lb. pentosus strains exhibited partial bile salt hydrolase activity. None of the strains inhibited the growth of the pathogens tested. Variable efficiency to adhere to Caco-2 cells was observed. This was the same regarding strains' susceptibility towards different antibiotics. None of the strains exhibited β-haemolytic activity. As a whole, 4 strains of Lb. pentosus, 3 strains of Lb. plantarum and 2 strains of Lb. paracasei subsp. paracasei were found to possess desirable in vitro probiotic properties similar to or even better than the reference probiotic strains Lb. casei Shirota and Lb. rhamnosus GG. These strains are good candidates for further investigation both with in vivo studies to elucidate their potential health benefits and in olive fermentation processes to assess their technological performance as novel probiotic starters.  相似文献   

4.
Fermentation and starch hydrolysis of a pre-cooked pearl millet–groundnut (MG) slurry inoculated with amylolytic lactic acid bacteria (ALAB) or by back slopping was investigated as a substitute for the addition of malt to prepare infant gruels. The ALAB collection strain Lb. plantarum A6, and the endogenous microflora provided by back slopping were more efficient in acidifying and partially hydrolysing starch in the MG slurry than Lb. plantarum 6.1, isolated from the traditional process in Burkina Faso. Large amounts of maltotriose and maltotetraose accumulated in slurry fermented by strain A6. No accumulation of maltose was observed, which could be an advantage to prevent the growth of microbial contaminants such as yeasts. Starch hydrolysis in the MG slurry inoculated with strain A6 or by back slopping enabled preparation of high-energy density gruels (84.7 ± 4.4 and 80.4 ± 23.8 kcal/100 g of gruel, respectively) of liquid consistency. However variability was higher with back slopping.  相似文献   

5.
制备冷冻干燥乳酸菌的相关影响因素的研究进展   总被引:1,自引:0,他引:1  
从技术和经济角度出发,让乳酸菌在干燥及其后续的贮藏过程中,尽可能多的存活是非常重要的。这篇文章主要综述与冷冻干燥乳酸菌制备的几个相关因素。  相似文献   

6.
Lactic acid bacteria (LAB) from traditional fermented sausages of the Basilicata region were investigated by ARDRA-PCR and RAPD-PCR for taxonomic identification at species and strain level and characterized on the basis of the growth and acidification at different temperatures, incubation times, levels of NaCl and KNO2, hydrolysis of sarcoplasmatic and myofibrillar proteins and antimicrobial, peptide/amino acid release and nitrate reductase activities.Lactobacillus sakei was the predominant species (67%) followed by Pediococcus pentosaceus (16%), Leuconostoc carnosum (8%), Lactobacillus plantarum (4%), Lactobacillus brevis (2%) and Leuconostoc pseudomesenteroides (2%). The technological characterization revealed that most of the isolates had good acidifying and proteolytic properties. Moreover, Lb. sakei strains showed antimicrobial ability, while Leuconostoc strains the highest reduction of nitrates.This work was a preliminary study in the formulation of autochthonous starter cultures in order to standardize the production process of sausages, to preserve their typical organoleptic and sensory characteristics and to improve the quality of final product.  相似文献   

7.
魏冉冉  方伟  霍贵成 《食品工业科技》2012,33(22):210-212,217
以从内蒙古呼伦贝尔市牧区采集的1份传统发酵酸牛奶样品为研究对象,对其进行乳酸菌的分离鉴定。通过传统纯培养法分离出17株菌,并对17株菌进行16SrDNA序列分析、多位点pheS序列分析和生理生化鉴定,鉴定的结果为11株乳酸乳球菌乳酸亚种、1株格式乳球菌、1株粪肠球菌、2株植物乳杆菌植物亚种及2株弯曲乳杆菌。乳酸乳球菌乳酸亚种为优势菌(占总分离菌株的64.7%)。  相似文献   

8.
One hundred and thirteen strains of lactic acid bacteria (LAB) were selected from 351 isolates from 15 samples of traditionally fermented household bushera from Uganda and also from laboratory-prepared bushera. Isolates were phenotypically characterised by their ability to ferment 49 carbohydrates using API 50 CHL kits and additional biochemical tests. Coliforms, yeasts and LAB were enumerated in bushera. The pH, volatile organic compounds and organic acids were also determined.

The LAB counts in household bushera varied between 7.1 and 9.4 log cfu ml−1. The coliform counts varied between <1 and 5.2 log cfu ml−1. The pH of bushera ranged from 3.7 to 4.5. Ethanol (max, 0.27%) was the major volatile organic compound while lactic acid (max, 0.52%) was identified as the dominant organic acid in household bushera.

The initial numbers of LAB and coliforms in laboratory-fermented bushera were similar; however, the LAB numbers increased faster during the first 24 h. LAB counts increased from 5.5 to 9.0 log cfu ml−1 during the laboratory fermentation. Coliform counts increased from 5.9 to 7.8 log cfu ml−1 at 24 h, but after 48 h, counts were less 4 log cfu ml−1. Yeasts increased from 4.3 to 7.7 log cfu ml−1 at 48 h, but thereafter decreased slightly. The pH declined from 7.0 to around 4.0. Lactic acid and ethanol increased from zero to 0.75% and 0.20%, respectively.

Lactic acid bacteria isolated from household bushera belonged to Lactobacillus, Streptococcus and Enterococcus genera. Tentatively, Lactobacillus isolates were identified as Lactobacillus plantarum, L. paracasei subsp. paracasei, L. fermentum, L. brevis and L. delbrueckii subsp. delbrueckii. Streptococcus thermophilus strains were also identified in household bushera. LAB isolated from bushera produced in the laboratory belonged to five genera (Lactococcus, Leuconostoc, Lactobacillus, Weissella and Enterococcus. Eight isolates were able to produce acid from starch and were identified as Lactococcus lactis subsp. lactis (four strains), Leuconostoc mesenteroides subsp. mesenteroides (one strain), Leuconostoc mesenteroides subsp. dextranicum (one strain), Weissella confusa (one strain) and L. plantarum (one strain).  相似文献   


9.
One hundred and seventy‐one strains of lactic acid bacteria were isolated from 44 traditional fermented milk samples from different region of Tibet. Among these samples, the concentrations of lactic acid bacteria varied from 10 5 to 10 9 colony forming unit/mL. The ratio of rod bacteria (71.3%) was higher than that of cocci (28.7%), and was considered to be the major population. Lactobacillus fermentum (31%) and Lactobacillus casei (28%) were the most predominant species among all these isolates. This study systematically analysed the microbial composition of traditional fermented milk in China, which may become a valuable source for further starter selection.  相似文献   

10.
Consumer demands have led to an increased interest in the use of natural antimicrobials for food protection. With the objective of developing novel products for enhancing the microbial safety of food, we have tested cell-free culture supernatants (CFS's) of eight antagonistic bacterial strains for their efficacy to inhibit Listeria monocytogenes in different food matrices. The antagonistic strains represented different members of the order Lactobacillales as well as one isolate of Staphylococcus sciuri and all showed strong inhibition of L. monocytogenes on agar plates. Cell-free supernatants were obtained after growing the bacteria in a yeast extract-glucose broth. In six of the CFS's, different class IIa bacteriocins, namely leucocin A, leucocin B, mundticin L, pediocin PA-1, sakacin A, and sakacin X, were identified as the major anti-listerial compounds. For the other two strains, the active substances could not be ascertained conclusively. The minimal effective concentration (MEC) of the individual CFS's to achieve a 2.3 log10 reduction of L. monocytogenes was determined in culture broth, whole milk, and ground beef at 4 °C. While all bacteriocin-containing CFS's were effective in broth at concentrations from 52 to 205 AU/ml, significant higher concentrations were needed when applied in food. Best results were obtained using CFS's containing pediocin PA-1, that displayed only three- and ten-times higher MEC's in milk (307 AU/ml) and ground meat (1024 AU/g) compared to broth, respectively. A twenty-fold increase in the MEC (2048 AU/ml) was observed for a mundticin L-containing fermentate, and a CFS containing leucocin A and B was inactivated more than fifty-fold (> 1280 AU/ml) in both food matrices. Remarkably, the sakacin A and sakacin X containing CFS's displayed very selective inactivation rates, in which sakacin A was only effective in meat (512 AU/g), while sakacin X was only effective in milk (2048 AU/ml). In all cases, inhibition of L. monocytogenes was only transient and surviving or resistant bacteria started growing after prolonged storage. These results highlight the importance of careful testing the effectiveness of bacteriocins in the food systems for which they are intended to be applied against the selected target and non-target bacteria. Furthermore, the outgrowth of surviving or resistant bacterial populations points out that the tested bacteriocins are not suited to assure full inhibition of L. monocytogenes in a food product, if not applied in combination with additional preservative measures.  相似文献   

11.
Mi Young Yoon  Han-Joon Hwang 《LWT》2008,41(5):925-933
Enterococcus faecium isolated from Chungkukjang, a Korean traditional fermented soybean food was studied for their functional characteristics as potential new starter culture and safety. Microbiological analysis of ripened Chungkukjang revealed the presence of an enterococcal population in numbers of up to 6 log CFU per g. Seven isolates with higher activity were selected for further study and the strains were identified as E. faecium. The E. faecium strains showed resistance against simulated gastrointestinal conditions such as acidic environment and the presence of bile salts. These strains also showed bile salt hydrolase activity but neither hemolytic activity nor virulence determinant such as gelE and efaAfm. All strains were susceptible to glycopeptides and lacked potential as vancomycin-resistant enterococci (VRE). Two strains, S2C10 and S2C11, showed inhibited the viability of Listeria monocytogenes in vitro. The ability was probably due to the production of bacteriocin. The lipase activity influenced the stability, while either acidic condition or high temperature did not play a significant role in the activity of the antimicrobial substances. The strains also produced thermostable listericidal antimicrobial substance. For this reason, the strains could be used as selected starters or protective cultures in soybean fermented food production.  相似文献   

12.
BACKGROUND: Sian‐sianzih (fermented clams) is a popular traditional fermented food in Taiwan. The lactic acid bacteria (LAB) microflora in sian‐sianzih have not been studied in detail. In this study, LAB from sian‐sianzih were isolated, characterized and identified. RESULTS: A total of 186 cultures of LAB were isolated from seven sian‐sianzih samples and 29 cultures were isolated from its main raw substrate: clams. The identification results revealed up to 11 distinct bacterial species belonging to five genera in sian‐sianzih, and three species belonging to two genera in clams. The most common bacterial genera in sian‐sianzih were Lactobacillus and Weissella, followed by Leuconostoc, Pediococcus and Lactococcus. A regional similarity in LAB, with differences in diversity, was observed in the current study. On the other hand, Lactococcus lactis subsp. lactis was the most common species found in raw clam samples. The results also suggested that greater LAB diversity could be observed in wild clams than in cultured ones. Furthermore, antibacterial activities of the isolates were determined, and one Weisella hellenica strain showed inhibitory activity against the indicator strain Lactobacilluas sakei JCM 1157T. A sensory assessment of seven sian‐sianzih samples was also performed and the results indicated that diversity of LAB has a great effect on its aroma and taste formation. CONCLUSION: The results demonstrate that various LAB species are distributed in sian‐sianzih and have a great effect on the flavor of sian‐sianzih. Copyright © 2011 Society of Chemical Industry  相似文献   

13.
The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain.  相似文献   

14.
A. Jagannath  P.S. Raju  A.S. Bawa 《LWT》2010,43(8):1197-1203
Nata or bacterial cellulose produced by Acetobacter xylinum was compared for its cryoprotective and carrier support potential for probiotic lactic acid bacteria against other established cryoprotectants like 10% skim milk, calcium alginate encapsulation or 0.85% physiological saline and distilled water. Individual lactic acid bacteria were grown in MRS broth in the presence of nata cubes or the bacterial suspension mixed with either powdered bacterial cellulose (PBC), 10% skim milk, saline or distilled water and freeze dried. These freeze dried cells were stored at temperatures of either 30 °C or 4 °C and periodically checked for viability. The freeze dried cells on carrier supports were directly used to prepare fermented milks to establish the activity of these cultures. Scanning electron microscopy was employed to visualize the support matrix with the attached lactic acid bacteria. The freeze drying process resulted in a 3.0 log cycle reduction in the colony forming units as compared to the original cell suspension in the case of all the lactic acid bacteria. The growth of lactic acid bacteria in the presence of bacterial cellulose (nata) offers a convenient and easy method to preserve bacteria for short durations and use it as a support to carry out other fermentation processes.  相似文献   

15.
Lee JY  Kim CJ  Kunz B 《Meat science》2006,72(3):437-445
The aim of the investigation was to identify strains of lactobacilli coming from kimchi with properties suitable for use as starter cultures in sausage fermentation. A total of 31 strains of lactobacilli were isolated from kimchi on the 4-6th day of fermentation at 20°C using MRS agar plates and identified on the basis of morphological, biochemical, and physiological characteristics. The isolates were identified as Leuconostoc mes.mes./dent (12.9%), Lactobacillus curvatus (9.7%), Lactobacillus brevis (35.5%), Lactobacillus sake (25.8%), and Lactobacillus plantarum (16.1%). Thus, 51.6% of the isolates were homo-fermentative or facultative hetero-fermentative bacteria and the rest (48.4%) were hetero-fermentative bacteria. Among them L. brevis, L. curvatus, L. plantarum, and L. sake were investigated for their growth profile and metabolism characteristics in the fluid (submerged) model-medium modified according to the special conditions of fermented sausages. Relatively good growth properties were found for L. brevis, L. plantarum, and L. sake with maximum numbers of 8.18, 8.51 and 8.17cfu/ml, respectively, whereas L. curvatus could not adapt to the special environmental conditions. Regarding souring properties, L. brevis showed little ability to decrease pH, whereas L. curvatus, L. plantarum, and L. sake showed relatively good acidifying properties. According to the results of glucose fermentation and its products, only L. plantarum exhibited homo-fermentative characteristics. As a result only L. plantarum among the isolates from kimchi had an ability to adapt to the complex environment of fermented sausage, which will thereby allow them to act as starter cultures and natural preservatives in sausage production.  相似文献   

16.
饶瑜  常伟  唐洁  李明元 《食品工业科技》2013,34(16):392-395
生物保鲜(biopreservation)是当今食品保藏和食品安全研究的热点。近年来,大量的研究致力于细菌素和产细菌素菌种在食品生物保鲜中的应用策略。本文主要介绍最新的产细菌素乳酸菌(LAB)在蔬菜发酵制品中的应用,通过将产细菌素乳酸菌作为发酵菌剂(starter culture)、保护菌剂(protective culture)或共培养菌剂(co-culture)运用到蔬菜的发酵制作中,以稳定蔬菜发酵过程中微生物体系,控制腐败和病原菌的存活和生长。   相似文献   

17.
以云南传统腌制食品为研究对象,采用纯培养分离、形态学观察及分子生物学鉴定方法进行乳酸菌多样性考察,并对分离菌株进行了发酵特性初步研究。结果表明,云南传统特色腌制食品中可培养乳酸菌多样性强,从11个样本中分离得到10株优势乳酸菌,涵盖乳杆菌属(Lactobacillus)、明串球菌属(Leuconostoc)、肠球菌属(Enterococcus)的菌株,分别为短乳杆菌(Lactobacillus brevis)1097b、哈尔滨乳杆菌(Lactobacillus harbinensis)1119b、干酪乳杆菌(Lactobacillus casei)1128b、戊糖乳杆菌(Lactobacillus pentosus)1133b、植物乳杆菌(Lactobacillus plantarum)1116b、1125b、1126b、1127b、肠系膜明串珠菌(Leuconostoc mesenteroides)1089b、粪肠球菌(Enterococcus faecium)1129b;另外,不同分离源的乳酸菌发酵特性差异显著,乳酸发酵类型多样性丰富。  相似文献   

18.
Plaa-som is a Thai fermented fish prepared from freshwater fish and various ingredients. In this study, two strains of lactic acid bacteria (LAB) isolated from natural plaa-som fermentation were used as starter cultures: Lactobacillus plantarum IFRPD P15 and Lactobacillus reuteri IFRPD P17. These strains were used as a mixed starter culture for plaa-som using an air-drying method (laminar airflow) with sterilized rice grains as the filler. This method produced a suitable starter culture, which was maintained at 4 °C for more than 20 weeks. LAB were the dominant bacteria in the starter culture and produced high acidity from 24 h until the end of fermentation. This resulted in decreased pH in plaa-som. L. plantarum IFRPD P15 was dominant as an acidity producer, whereas L. reuteri IFRPD P17 showed an ability to suppress and eliminate pathogenic bacteria such as Escherichia coli within 24 h. The use of a single starter culture for plaa-som resulted in incomplete suppression of pathogenic bacteria and elimination of E. coli. Thus, L. plantarum IFRPD P15 and L. reuteri IFRPD P17 have great potential for use as a mixed starter culture in plaa-som fermentation and may possibly help to reduce fermentation time.  相似文献   

19.
Fura is a millet-based spontaneously fermented dumpling produced and consumed in parts of West Africa, particularly Nigeria, Burkina Faso and Ghana. From eight traditional fura production sites in northern Ghana, 862 lactic acid bacteria were isolated and identified to species level using a combination of genotypic and phenotypic methods including (GTG)5-based PCR fingerprinting and 16S rRNA gene sequencing, multiplex PCR by means of recA gene sequence comparison, conventional morphological characteristics and carbohydrate fermentation profiling. During millet dough fermentation, pH decreased from 5.6–6.4 to 4.1–3.7 and total lactic acid bacteria (LAB) counts increased from 4.4–5.3 to 7.9–9.2 log10 (cfu/g). The initial stages of the fermentation were characterized by co-dominance of homo- and heterofermentative species of Pediococcus acidilactici, Weisella confusa, Lactobacillus fermentum, Lactobacillus reuteri, Lactobacillus salivarius, and Lactobacillus paraplantarum whereas L. fermentum was dominating at the end of the fermentation. L. fermentum was predominant in all fermentations (p < 0.05) and a high uniformity was observed among production sites regarding the dominance of L. fermentum. L. fermentum and W. confusa were isolated in all production sites and almost at all fermentation stages indicating that they are indigenous to traditional fura processing. The other LAB bacteria species which comprised a minor proportion of the total LAB occurred occasionally and in an irregular pattern among the production sites.  相似文献   

20.
Technological and safety-related properties were analyzed in lactic acid bacteria isolated from Spanish dry-cured sausages in order to select them as starter cultures. In relation to technological properties, all the strains showed significative nitrate reductase activity; Lactobacillus plantarum, Lactobacillus paracasei and 52% of the Enterococcus faecium strains showed lipolytic activity and only Lactobacillus sakei strains (43%) were able to form biofilms. Related to safety aspects, E. faecium strains were the most resistant to antibiotics, whereas, L. sakei strains were the most sensitive. In relation to virulence factors, in the E. faecium strains analyzed, only the presence of efaA gene was detected. The analysis of biogenic amine production showed that most E. faecium strains and L. sakei Al-142 produced tyramine. In conclusion, L. paracasei Al-128 and L. sakei Al-143 strains possess the best properties to be selected as adequate and safe meat starter cultures.  相似文献   

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