scholarly journals Polyphasic Characterisation of Non-Starter Lactic Acid Bacteria from Algerian Raw Camel’s Milk and Their Technological Aptitudes

2020 ◽  
Vol 58 (3) ◽  
pp. 260-272
Author(s):  
Yasmine Saidi ◽  
Beatriz del Rio ◽  
Djamel Eddine Senouci ◽  
Begoña Redruello ◽  
Beatriz Martinez ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Methyl Acetate ◽  
Experimental Approach ◽  
Phenotypic Traits ◽  
Phenotypic Characteristics ◽  
Milk Samples ◽  
Adjunct Cultures ◽  
Camel's Milk

Research background. Consumption of spontaneously fermented camel´s milk is usual in Algeria, making it a feasible source of diverse lactic acid bacteria (LAB) with the potential to be used as adjunct cultures to improve quality and safety of dairy fermented products. Experimental approach. Twelve raw camel´s milk samples were used as source of indigenous LAB, which were further characterised by examining 39 phenotypic traits with technological relevance. Results and conclusions. Thirty-five non-starter LAB (NSLAB) were isolated from 12 Algerian raw camel's milk samples and they were microbiologically, biochemically and genetically characterised. Some isolates showed proteolytic activity, acidifying capacity, the ability to use citrate, and to produce dextran and acetoin. Ethanol, acetaldehyde, methyl acetate, acetoin and acetic acid were the major volatile compounds detected. Cluster analysis performed using the UPGMA method, and based on the thirty-nine phenotypic characteristics investigated, reflected the microbial diversity that can be found in raw camel´s milk. Novelty and scientific contribution. The isolated strains, from a non-typical source, showed interesting technological traits to be considered as potential adjunct cultures. Cluster analysis based on the phenotypic characteristics examined turned out to be a useful tool for the typification of isolates when no genetic information is available. These findings may be of use towards an industrialised production of camel's milk dairy products.

scholarly journals Screening and enumeration of lactic acid bacteria in milk using three different culture media in Petrifilm™ Aerobic Count plates and conventional pour plate methodology

2007 ◽  
Vol 74 (4) ◽  
pp. 387-391 ◽  
Author(s):  
Maria BT Ortolani ◽  
Gabriela N Viçosa ◽  
Vanerli Beloti ◽  
Luís A Nero
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Culture Media ◽  
Skim Milk ◽  
Raw Milk ◽  
Excellent Correlation ◽  
Anaerobic Conditions ◽  
Milk Samples ◽  
Experimental Inoculation

This study aimed to compare Petrifilm™ Aerobic Count (AC) plates and the conventional pour plate methodology using de Mann-Rogosa-Sharpe (MRS), Kang-Fung (KF) and Kang-Fung-Sol (KFS) culture media for screening and enumeration of lactic acid bacteria (LAB) in milk. Suspensions of 10 LAB species in reconstituted powder skim milk and 30 raw milk samples, without experimental inoculation, were tested. For selective enumeration, all samples were previously diluted in MRS, KF and KFS broths and then plated in Petrifilm™ AC and conventional pour plate methodology, using the same culture media with added agar. All plates were incubated at 37°C for 48 h in anaerobic conditions. Differences in the counts were observed only for raw milk samples using KFS in conventional methodology, when compared with the counts obtained from MRS and KF (P⩽0·05). The results showed excellent correlation indexes between both methodologies using the three culture media for LAB suspensions (r=0·97 for MRS, KF and KFS). For raw milk samples, the correlation indexes were excellent (r=0·97, for MRS) and good (r=0·84 for KF, and r=0·82 for KFS), showing some interference in Petrifilm™ AC when supplements were added, especially lactic acid. These results indicate the possibility of using Petrifilm™ AC plates for enumeration of LAB in milk, even with the use of selective supplements.

scholarly journals Comparative detection of coliform organisms in milk and water by the presumptive coliform test

1943 ◽  
Vol 43 (2) ◽  
pp. 129-135 ◽  
Author(s):  
H. Barkworth ◽  
J. O. Irwin
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Small Proportion ◽  
Present Experiment ◽  
False Negative ◽  
Poisson Series ◽  
Milk Samples ◽  
Physico Chemical ◽  
Chemical Constitution ◽  
Fermentation Test

It has been shown (Barkworth & Irwin, 1938) that the distribution of coliform organisms in milk follows a Poisson series, and on this basis it should be possible to estimate the population from the results of replicate tests at several dilution levels by reference to tables. In later experiments with water (Barkworth & Irwin, 1941), it was found that the number of positive tubes did not always reach expectation, having regard to the known numbers of organisms inoculated. The peculiar physico-chemical constitution of milk naturally raises the question whether coliform organisms, though present, might fail to give a positive reaction in the presumptive test. It is well known that in favourable circumstances lactic acid bacteria will overgrow all other organisms in milk. In the presumptive test the greatest concentration of milk in routine technique is 1 ml. of milk in 5 ml. of medium. This dilution would not affect the ratio of coliform organisms to lactic acid bacteria. Even when the coliform contamination at the time of testing is ‘present in 0·001 ml.’ the agreement with the fermentation test is only about 50% (Barkworth, 1929). It will be argued that the gas tube would disclose the presence of gas in more cases than the fermentation test, nevertheless it is not perfect, for Chalmers (1928) recovered Bact. coli from plates of 1: 10 dilution of samples of milk which had given a negative presumptive test. There is therefore some reason to expect a small proportion of false negative coliform results to occur with milk samples, and the object of the present experiment was to see if inoculation with a known number of organisms would produce similar numbers of positive tubes in milk and in water.

The Effects of Cultivating Lactic Starter Cultures with Bacteriocin-Producing Lactic Acid Bacteria

2001 ◽  
Vol 64 (1) ◽  
pp. 81-86 ◽  
Author(s):  
A. OUMER ◽  
S. GARDE ◽  
P. GAYA ◽  
M. MEDINA ◽  
M. NUÑEZ
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Starter Culture ◽  
Starter Cultures ◽  
The Other ◽  
Aminopeptidase Activity ◽  
Adjunct Cultures ◽  
Nisin Z ◽  
Bacteriocin Producer ◽  
Test Organisms

The effects of bacteriocins produced by six strains of lactic acid bacteria on 9 mesophilic and 11 thermophilic commercial starter cultures were investigated in mixed cultures of commercial starters with bacteriocin-producing strains in milk. The bacteriocins produced by the test organisms were nisin A, nisin Z, lacticin 481, enterocin AS-48, a novel enterocin, and a novel plantaricin. Mesophilic commercial starters were in most cases tolerant of bacteriocins, with only two of the starters being partially inhibited, one by four and the other by two bacteriocins. The aminopeptidase activities of mesophilic starters were generally low, and only one of the combinations of mesophilic starter–bacteriocin producer gave double the aminopeptidase activity of the starter culture without the bacteriocin producer. Thermophilic commercial starters were more sensitive to bacteriocins than mesophilic starters, with six thermophilic starters being partially inhibited by at least one of the bacteriocins. Their aminopeptidase activities were generally higher than those of the mesophilic starters. The aminopeptidase activities of seven thermophilic starters were increased in the presence of bacteriocins, by factors of up to 9.0 as compared with the corresponding starter cultures alone. Bacteriocin-producing strains may be used as adjunct cultures to mesophilic starters for the inhibition of pathogens in soft and semihard cheeses, because mesophilic starters are rather tolerant of bacteriocins. Bacteriocin producers may also be used as adjunct cultures to thermophilic starters of high aminopeptidase activity, more sensitive to lysis by bacteriocins than mesophilic starters, for the acceleration of ripening in semihard and hard cheeses.

scholarly journals Evaluation of the Hygienic Quality of Raw Cow’s Milk in Oujda City Morocco

2017 ◽  
Vol 14 (2) ◽  
pp. 587-591
Author(s):  
K. Mchiouer ◽  
S. Bennani ◽  
N. Sh. El-Gendy ◽  
M. Meziane
Keyword(s):  
Staphylococcus Aureus ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Fecal Coliform ◽  
Raw Milk ◽  
Total Coliform ◽  
Aerobic Bacteria ◽  
Milk Samples ◽  
Fecal Streptococci

ABSTRACT: The aim of this study is to determine the microbiological quality of raw cows’ milk of Oujda city. Raw milk samples are collected randomly between June 2014 and May 2015 from 20 Mahlaba (dairies) for microbiological evaluation. The samples are analyzed to determine total mesophilic aerobic bacteria (TMAB), total coliform, fecal coliform, staphylococcus aureus, fecal streptococci, proteolytic bacteria and lactic acid bacteria. The results of bacterial count showed that there is a variation between all the milk samples and a period effect is also observed. The mean counts of total mesophilic aerobic bacteria from all sale points are between 1.76×106 and 40.17×106 CFU/ml. Milk samples reveled counts total coliform and fecal coliform ranging from 0.58×105 to 11.10×105 CFU/ml and from 0.60×103 to 14.64×103 CFU/ml, respectively. Staphylococcus aureus are also detected in all samples with counts ranging from 0.35 ×103 to 3.08×103 CFU/ml. Fecal streptococci are found in all milk samples, at counts ranging from 0.16 ×102 to 2.18 ×102 CFU/ml. And finally, proteolytic and lactic acid bacteria are between 0.3×103 and 2.86×103 CFU/ml and 2.37×106 and 24.14 ×106 CFU/ml respectively. These results indicate a lack of compliance with good manufacturing practice at milking, collection and transportation of raw milk.

scholarly journals Improving the conjugated linoleic acid content and the sensorial characteristics of Argentinean semi-hard goat cheeses by adding cultures of native lactic acid bacteria

2019 ◽  
Vol 69 (4) ◽  
pp. 251-263
Author(s):  
Natalia Taboada ◽  
Carina Van Nieuwenhove ◽  
Roxana Medina ◽  
Soledad López Alzogaray
Keyword(s):  
Fatty Acids ◽  
Lactic Acid ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Lactic Acid Bacteria ◽  
Conjugated Linoleic Acid ◽  
Adjunct Cultures ◽  
Δ9 Desaturase ◽  
Native Strains ◽  
Esterase Activities

In this study the physicochemical, microbiological, and fatty acid compositions together with the specific esterase activities of semi-hard goat cheeses made from native strains as starter and adjunct cultures were evaluated and compared against those of manufactured using commercial culture cheeses. The physicochemical composition was similar among cheeses, while the lactic acid bacteria were the predominant microbiota in all samples. The highest specific esterase activities were detected in cheeses with native strains. The fatty acid profile was significantly affected by native strains during the ripening time (60 days) since the conjugated linoleic acid (CLA) level increased from 0.60 to 1.03 g 100 g-1 of fatty acids, whereas cheeses with commercial starter showed a CLA content of about 0.60 g of fatty acids. In cheeses with native strains, it was detected the highest desirable fatty acids, Δ9-desaturase and CLA desaturase indexes and the lowest atherogenicity index. The native strains inoculated as starter and adjunct cultures, grew conveniently in the cheese, developed their full potential as reflected by the profile of the metabolites released during ripening and in the global sensory perception of cheeses, and contributed thus to the development of a healthier food.

Isolation of exopolysaccharides producing lactic acid bacteria from dairy products

2015 ◽  
Vol 34 (4) ◽  
Author(s):  
Prasad Patil ◽  
Akanksha Wadehra ◽  
Kanchan Munjal ◽  
Pradip Behare
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Molecular Identification ◽  
Dairy Products ◽  
Raw Milk ◽  
Fermented Milk ◽  
Milk Products ◽  
Milk Samples ◽  
Fermented Milk Products ◽  
Exopolysaccharides Production

Currently, much attention is being paid for improving the texture of food by screening the new exopolysaccharides (EPS) producing strains. The aim of the present work was to isolate EPS producing Lactic acid bacteria (LAB) strains from raw milk and milk products samples. Total of thirty eight dahi, lassi and raw milk samples were collected from different villages and towns of Karnal and Delhi District. The samples were plated on milk agar and colonies showing ropy polysaccharides production were subjected to biochemical test. After molecular identification 2 were found as <italic>S. thermophilus</italic>, 2 were <italic>Lb. rhamnosus</italic> and 2 were confirmed as <italic>Lb. fermentum</italic>. Two <italic>S. thermophilus</italic> strains (PD7 and PD11) and <italic>Lb. fermentum</italic> strains (AL6 and AD3) showed better curdling pattern, acidity, exopolysaccharides production, and sensory properties. These cultures can be used for manufacture of indigenous fermented milk products.

scholarly journals Oenococcus kitaharae sp. nov., a non-acidophilic and non-malolactic-fermenting oenococcus isolated from a composting distilled shochu residue

2006 ◽  
Vol 56 (10) ◽  
pp. 2345-2348 ◽  
Author(s):  
Akihito Endo ◽  
Sanae Okada
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Novel Species ◽  
Malolactic Fermentation ◽  
Oenococcus Oeni ◽  
Rrna Gene ◽  
16S Rrna Gene Sequences ◽  
Phenotypic Characteristics ◽  
Optimum Ph ◽  
The 16S Rrna Gene

Six strains of lactic acid bacteria were isolated in Japan from a composting distilled shochu residue. The six isolates grew poorly on MRS agar and slowly in MRS broth. The 16S rRNA gene sequences did not show high levels of similarity to those of the recognized species of lactic acid bacteria, and formed a subcluster within the cluster comprising obligately heterofermentative lactic acid bacteria closely related to Oenococcus oeni. The levels of DNA–DNA relatedness revealed that the isolates belonged to the same taxon and were genetically separate from O. oeni. Furthermore, various phenotypic characteristics such as the optimum pH for growth, malolactic fermentation and resistance to 10 % ethanol revealed that the isolates are distinguishable from O. oeni. On the basis of their phylogenetic and phenotypic characteristics, the isolates represent a novel species, for which the name Oenococcus kitaharae sp. nov. is proposed. The type strain is NRIC 0645T (=JCM 13282T=DSM 17330T).

scholarly journals Identification of exopolysaccharides-producing lactic acid bacteria from Burkina Faso fermented milk samples

2003 ◽  
Vol 3 (3) ◽  
pp. 189-194 ◽  
Author(s):  
Savadogo Aly ◽  
A. T. Ouattara Cheik ◽  
W. Savadogo Paul ◽  
Barro Nicolas ◽  
S. Ouattara Aboubacar ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Burkina Faso ◽  
Fermented Milk ◽  
Milk Samples

scholarly journals Stability of Lactic Acid Bacteria in Pasteurized Cow’s and Goat’s Milk

2019 ◽  
Vol 1 (4) ◽  
pp. 77-82
Author(s):  
Nurfarhana Syed Malik ◽  
Mohd. Nizam Lani ◽  
Fauziah Tufail Ahmad
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Viable Count ◽  
Plate Count ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Goat’S Milk ◽  
Different Types ◽  
Goat's Milk ◽  
The Stability

This study was done to determine the effect of pasteurization on the stability of lactic acid bacteria (LAB) and its enzyme in raw and pasteurized cow’s and goat’s milk. The total viable count for plate count of the bacterial growth concentration was higher in both pasteurized cow’s and goat’s milk at 2.48 log CFU/ml. This is followed by raw cow’s milk (1.59 log CFU/ml) and raw goat’s milk (0.65 log CFU/ml). Lactic acid bacteria (LAB) was found to be similar in both raw cow’s and goat’s milk (p>0.05), and pasteurized milk of both animals also contained the same amount of LAB (p>0.05). LAB was still detected in pasteurized milk (p<0.05), indicating the stability of LAB against the pasteurization temperature. Interestingly, based on API ZYM assay kit results, there were nine different enzymes detected in all samples, which were leucinearylamidase, valinearylamidase,cystinearylamidase, trypsin, α-chymotrypsin, naphthol-AS-BI-phosphohydrolase, α-glucosidase, β-glucosidaseand acid phosphatise. The results revealed that different types of lactic acid bacteria were detected in treated and non-treated milk samples produced by different animals, indicating the different stability levels of LAB against pasteurization.

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