scholarly journals Polyphasic Approach to Bacterial Dynamics during the Ripening of Spanish Farmhouse Cheese, Using Culture-Dependent and -Independent Methods

2008 ◽  
Vol 74 (18) ◽  
pp. 5662-5673 ◽  
Author(s):  
Antonio M. Martín-Platero ◽  
Eva Valdivia ◽  
Mercedes Maqueda ◽  
Inés Martín-Sánchez ◽  
Manuel Martínez-Bueno

ABSTRACT We studied the dynamics of the microbial population during ripening of Cueva de la Magahá cheese using a combination of classical and molecular techniques. Samples taken during ripening of this Spanish goat's milk cheese in which Lactococcus lactis and Streptococcus thermophilus were used as starter cultures were analyzed. All bacterial isolates were clustered by using randomly amplified polymorphic DNA (RAPD) and identified by 16S rRNA gene sequencing, species-specific PCR, and multiplex PCR. Our results indicate that the majority of the 225 strains isolated and enumerated on solid media during the ripening period were nonstarter lactic acid bacteria, and Lactobacillus paracasei was the most abundant species. Other Lactobacillus species, such as Lactobacillus plantarum and Lactobacillus parabuchneri, were also detected at the beginning and end of ripening, respectively. Non-lactic-acid bacteria, mainly Kocuria and Staphylococcus strains, were also detected at the end of the ripening period. Microbial community dynamics determined by temporal temperature gradient gel electrophoresis provided a more precise estimate of the distribution of bacteria and enabled us to detect Lactobacillus curvatus and the starter bacteria S. thermophilus and L. lactis, which were not isolated. Surprisingly, the bacterium most frequently found using culture-dependent analysis, L. paracasei, was scarcely detected by this molecular approach. Finally, we studied the composition of the lactobacilli and their evolution by using length heterogeneity PCR.

2017 ◽  
Vol 1 (1) ◽  
pp. 89-90 ◽  
Author(s):  
Hanna Aljaksandrauna Bareika ◽  
Anatasija Vyachaslavauna Sidarenka ◽  
Galina Ivanovna Novik

Abstract From fresh and fermented vegetables (cucumber, sauercraut, eggplant), cereals (wheat, rice), legumes (soy) 37 cultures of lactic acid bacteria were isolated. Based on biochemical characteristics, MALDI-TOF MS protein profiling and 16S rRNA gene sequencing they were identified as representatives of Lactobacillus, Lactococcus, Leuconostoc, Pediococcus and Enterococcus genera. Six members of Lactobacillus genera and two members of Leuconostoc genera actively producing EPS were selected for further investigation as components of starters for production of special dietetic foodstuffs.


2019 ◽  
Vol 71 (1) ◽  
pp. 95-102
Author(s):  
Svetlana Bogdanovic ◽  
Aleksandra Jelusic ◽  
Tanja Beric ◽  
Ivan Nikolic ◽  
Bojana Danilovic ◽  
...  

The ?Pirot ?ironed? sausage? (Pis) is a traditional, dry, fermented product originating from the town of Pirot, situated in southeastern Serbia. This product is made from different types of meat (goat, sheep, beef and donkey) and spices, without additives or starter cultures. Pis is an organic, unprocessed product, without heat or smoke treatment. The aim of this study was to characterize 120 isolates of lactic acid bacteria (LAB) from Pis produced by six different brands during a two-year period using phenotypic and genetic identification. Preliminary characterization of the LAB was based on general morphology and biochemical tests. Repetitive elements such as REP, BOX and GTG5, found in the genome of these bacteria, and randomly amplified polymorphic DNA-polymerase chain reaction (RAPD PCR) sequences were used for determination of genetic polymorphism. Identification by 16S rRNA gene sequencing showed the presence of only two LAB species, Lactobacillus sakei (76%) and Leuconostoc mesenteroides (24%). However, genetic polymorphism was detected using fingerprinting methods. In comparison with other primers, the profiles obtained with GTG5 showed the highest heterogeneity for most of the tested isolates, with sequencing results additionally confirming its discriminatory power. In addition, M13 RAPD primer also produced satisfactory separation of the tested isolates.


2021 ◽  
Vol 9 (7) ◽  
pp. 1346
Author(s):  
Mariana Petkova ◽  
Petya Stefanova ◽  
Velitchka Gotcheva ◽  
Angel Angelov

Traditional sourdoughs in Bulgaria were almost extinct during the centralized food production system. However, a rapidly developing trend of sourdough revival in the country is setting the demand for increased production and use of commercial starter cultures. The selection of strains for such cultures is based on geographical specificity and beneficial technological properties. In this connection, the aim of this study was to isolate, identify and characterize lactic acid bacteria (LAB) and yeasts from typical Bulgarian sourdoughs for the selection of strains for commercial sourdough starter cultures. Twelve samples of typical Bulgarian sourdoughs were collected from different geographical locations. All samples were analyzed for pH, total titratable acidity and dry matter content. Enumeration of LAB and yeast was also carried out. Molecular identification by 16S rDNA sequence analysis was performed for 167 LAB isolates, and 106 yeast strains were identified by ITS1-5.8S-ITS2 rRNA gene partial sequence analysis. The LAB strains were characterized according to their amylolytic and proteolytic activity and acidification capacity, and 11 strains were selected for further testing of their antimicrobial properties. The strains with the most pronounced antibacterial and antifungal activity are listed as recommended candidates for the development of starter cultures for sourdoughs or other food products.


Author(s):  
Jinghui Yao ◽  
Jing Gao ◽  
Jianming Guo ◽  
Hengan Wang ◽  
En Zhang ◽  
...  

The consumption of cheese in China is increasing rapidly. Little is known about the microbiota, the presence of antibiotic-resistant bacteria, or the distribution of antibiotic resistance genes (ARGs) in commercially-produced cheeses sold in China. These are important criteria for evaluating quality and safety. Thus, this study assessed the metagenomics of fifteen types of cheese using 16S rRNA gene sequencing. Fourteen bacterial genera were detected. Lactococcus , Lactobacillus , and Streptococcus were dominant based on numbers of sequence reads. Multidrug-resistant lactic acid bacteria were isolated from most of the types of cheese. The isolates showed 100% and 91.7% resistance to streptomycin and sulfamethoxazole, respectively, and genes involved in acquired resistance to streptomycin ( strB) and sulfonamides ( sul2) were detected with high frequency. To analyze the distribution of ARGs in the cheeses in overall, 309 ARGs from eight categories of ARG and nine transposase genes were profiled. A total of 169 ARGs were detected in the 15 cheeses; their occurrence and abundance varied significantly between cheeses. Our study demonstrates that there is various diversity of the bacteria and ARGs in cheeses sold in China. The risks associated with multidrug resistance of dominant lactic acid bacteria are of great concern.


2020 ◽  
Vol 25 (6) ◽  
pp. 2079-2085
Author(s):  
LIN-HU NAN ◽  
◽  
YI-SHENG CHEN ◽  
HUI-CHUNG WU ◽  
YU-CHING SU ◽  
...  

Lychee is a popular fruit in China and southeastern Asia. Although it is very popular, the microbiota of lactic acid bacteria (LAB) associated with lychee remains poorly described. Lychee samples from seven different markets located in three cities in Taiwan were collected and a total of 104 LAB were isolated. Through RFLP analyses of 16S rDNA and rpoA genes for grouping and 16S rRNA gene sequencing, these isolates were finally divided into 6 groups (A to F). The most common genera of LAB in lychee samples were Weissella and Leuconostoc. Weissella confusa strain E was found to produce a bacteriocin active against Listeria monocytogenes and some other Gram-positive bacteria. Mass spectrometry analysis revealed the bacteriocin mass to be approximately 3426.77 Da, which is different to other known Weissella bacteriocins. In addition, strain MB7 included in the genus Leuconostoc was identified as potential novel species or subspecies on the basis of phylogenetic analysis of 16S rRNA, rpoA and pheS gene sequences. Thus, this is the first report describing the distribution and varieties of LAB associated with lychee fruits. In addition, one potential novel LAB species or subspecies and one potential novel bacteriocin were also reported in this study.


2021 ◽  
Vol 71 (4) ◽  
pp. 2553
Author(s):  
Y. N. DOĞAN ◽  
Ö. F. LENGER ◽  
M. DÜZ ◽  
I. DOĞAN ◽  
Z. GÜRLER

Biogenic amines (BAs) are formed by the decarboxylation of amino acids in fermented products and accumulate in these products due to the fermentation conditions, the natural microflora of the product, and the diversity of amino acids. Although they are inhibited by the human body, they are a hazard to public health. Starter cultures used in fermented sucuk should not have amino acid decarboxylase properties. The aim of the present study was to determine proteolytic activity, histidine and tyrosine decarboxylase enzyme activities of Lactobacillus plantarum, Lactobacillus sake, and Lactobacillus curvatus species and to evaluate the level of BA in sucuk groups containing these lactic acid bacteria (LAB). It was determined that none of the LAB generated these activities. While histamine values were not statistically significant in the sucuk groups (P> 0.05), tyramine values showed statistically significant differences (P<0.05). The tyramine values of GI ( = 1.43 ± 0.75) and GIII ( = 2.73 ± 1.02) groups were lower than C ( = 8.97 ± 5.29) and GII ( = 7.58 ± 2.90) groups. According to the results of the study, L. plantarum or L. curvatus can provide more reliable fermented products with respect to tyramine formation. L. plantarum, L. sake, and L. curvatus could reduce histamine and tyramine formation in fermented sucuk.


2021 ◽  
Vol 15 (01) ◽  
pp. 102-112
Author(s):  
Nazar Hussain ◽  
Muhammad Tariq ◽  
Per Erik Joakim Saris ◽  
Arsalan Zaidi

Introduction: Probiotic and postbiotic potential of thirty-two strains of lactic acid bacteria (LAB), obtained earlier from artisanal dairy sources in Pakistan, have been investigated against major multi-drug resistant (MDR) and food borne pathogenic bacteria. Methodology: LAB strains were identified by 16S rRNA gene sequencing and their antibacterial activity was assessed by the microdilution method. Four LAB isolates, Weissella confusa PL6, Enterococcus faecium PL7, and Lactobacillus delbrueckii PL11 and PL13 were shortlisted. Their ability to degrade lactose and safety for human consumption in terms of hemolysis and antibiotic susceptibility were assessed in vitro. The antibacterial components in the cell-free supernatants (CFSs) of isolate cultures were characterized biochemically by HPLC. Results: Acid neutralization but not protease treatment abolished the antibacterial activity of CFSs. Lactic, acetic and propionic acids were the main acids in the CFSs, and acid production peaked in the stationary phase of growth. The antibacterial activity of the LAB cultures resulted from secretion of organic acids that lowered the pH. The strains exhibited variable ability to degrade lactose and were non-hemolytic and susceptible to the most common antibiotics. Conclusions: These LAB strains are probiotic candidates for further investigation of their postbiotic role in naturally preserving processed foods and for attenuation of lactose intolerance.


2019 ◽  
Vol 8 (1) ◽  
pp. 5 ◽  
Author(s):  
Anshul Sharma ◽  
Jasmine Kaur ◽  
Sulhee Lee ◽  
Young-Seo Park

The present work aimed at tracking intentionally inoculated lactic acid bacteria (LAB) strains in yogurt and probiotic powder. Leuconostoc (Leu.) mesenteroides (11251), Lactobacillus (L.) brevis (B151), and Lactobacillus plantarum (LB41K) strains were tracked in yogurt, and L. plantarum (LB41P) was tracked in a commercial probiotic powder. The yogurt was intentionally inoculated with the selected bacterial strains. Two types of yogurt with known and unknown bacterial pools were utilized. The standard 16S rRNA gene sequencing was used to evaluate the initial screening. The molecular typing tools, random amplified polymorphic DNA (RAPD), repetitive element palindromic PCR (rep-PCR), and comparative gene sequence analysis of selected housekeeping loci were used to track the inoculated dubious strains. Out of 30 random selections for each inoculation, the developed method identified seven (11251), nine (B151), and five (LB41K) colonies in the yogurt. The validation was performed by identifying 7 colonies (LB41P) out of 30 in the probiotic powder. The DNA banding profiles and the gene sequence alignments led to the identification of the correct inoculated strains. Overall, the study summarizes the use of molecular tools to identify the deliberately inoculated LAB strains. In conclusion, the proposed polyphasic approach effectively tracked the intentionally inoculated strains: Leu. mesenteroides, L. brevis, and L. plantarum (LB41K) in yogurt and L. plantarum (LB41P) in probiotic powder. The study demonstrates how to track industrially relevant misused LAB strains in marketable food products.


2016 ◽  
Vol 62 (7) ◽  
pp. 550-561 ◽  
Author(s):  
Amandine Fessard ◽  
Emmanuel Bourdon ◽  
Bertrand Payet ◽  
Fabienne Remize

From 6 samples of tropically grown fruits and leaves, 10 lactic acid bacteria belonging Leuconostoc, Weissella, and Lactobacillus species were isolated and identified by 16S rRNA gene sequencing and (GTG)5 fingerprinting. Acidification kinetics determined from BHI broth cultures showed genus-related patterns. In particular, Weissella cibaria appeared to act as a potent acidifier. Tolerance of isolates to acid, oxidative, or salt stress was highly variable and strain dependent. Isolate S14 (Leuconostoc pseudomesenteroides) growth was not affected by the presence of 0.05% H2O2, while Lactobacillus spp. isolates (S17 and S29) were the most tolerant to pH 4.5. The growth of 4 isolates, S5 (Leuconostoc mesenteroides), S14 and S10 (Leuconostoc pseudomesenteroides), and S27 (W. cibaria), was not affected by 5% NaCl. Nutritional beneficial properties were examined through measurement of antioxidant activities of short-term fermented pineapple juice, such as LDL oxidation and polyphenol content, and through exopolysaccharide formation from sucrose. Two isolates, S14 and S27, increased the antioxidant capacity of pineapple juice. The robust capacity of W. cibaria and of Leuconostoc pseudomesenteroides for vegetable lactic fermentation aimed to ameliorate food nutritional and functional quality was highlighted.


2021 ◽  
Vol 22 (7) ◽  
Author(s):  
IMMANUELLA BERLIANA ELVANI HUTAJULU ◽  
PERISKILA DINA KALI KULLA ◽  
Endah Retnaningrum

Abstract. Hutajulu IBE, Kulla PDK, Retnaningrum E. 2021. Diversity of lactic acid bacteria isolated during fermentation of indigenous cassava obtained from Sumba, East Nusa Tenggara, Indonesia. Biodiversitas 22: 2561-2570. Traditional fermented food products hold a great significance in the routine diet of Indonesian inhabitants. The present study investigated the diversity of lactic acid bacteria (LAB) found in fermented indigenous cassava, ubi karet busuk, produced in Sumba, East Nusa Tenggara, Indonesia. The isolated LAB was characterized for their phenotypic, biochemical, and molecular traits, which involved 16S rRNA gene sequencing, determination of lactic acid fermentation pathway, and measurement of b-glucosidase and tannase activity in the LAB strains. During fermentation, 15 LAB strains were obtained from the cassava. Among these, 93.33% strains were found to be homofermentative, whereas 6.73% strains displayed heterofermentative traits. BLASTn and phylogenetic analysis classified 15 LAB strains into six species, namely Enterococcus faecium, Enterococcus faecalis, Enterococcus casseliflavus, Leuconostoc mesenteroides, Lactococcus lactis, and Enterococcus sp. Among these, 10 LAB strains displayed b-glucosidase activity, with highest enzyme activity of 7.13 U/mL recorded in L. lactis F14IS3. Interestingly, two of these strains also showed expression of tannase, with F6IS1 strain displaying highest enzyme activity of 38.23 U/mL. Thus, the study results highlighted the suitability of these b-glucosidase and tannase-producing LAB strains to be used as a starter in the fermentation of cassava and other substrates such as vegetables, fruits, and legumes. These strains can also be utilized in animal feed, food, and beverage industries.


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