scholarly journals Assessment of the Spoilage Microbiota during Refrigerated (4 °C) Vacuum-Packed Storage of Fresh Greek Anthotyros Whey Cheese without or with a Crude Enterocin A-B-P-Containing Extract

Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2946
Author(s):  
Nikoletta Sameli ◽  
Eleni Sioziou ◽  
Loulouda Bosnea ◽  
Athanasia Kakouri ◽  
John Samelis
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
Leuconostoc Mesenteroides ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Spoilage Bacteria ◽  
Rrna Sequencing ◽  
Leuconostoc Lactis ◽  
Enterocin A

Although fresh whey cheeses are prone to rapid deterioration, mainly by psychrotrophic Gram-negative bacteria and lactic acid bacteria (LAB), data on the specific spoilage species in traditional Greek whey cheeses are scarce. Therefore, this study quantified growth and characterized the primary spoilage bacteria in fresh Anthotyros whey cheeses stored at 4 °C in a vacuum for 40 days, without or with an added 5% (v/w) of an enterocin A-B-P crude extract (CEntE). Psychrotrophic Pseudomonas spp., Aeromonas spp., Hafnia spp. and Serratia spp. grew faster than LAB during early storage. However, LAB outgrew the Gram-negative bacteria and prevailed by mid to late storage in all cheese batches, causing a strong or milder batch-dependent natural acidification. Two major non-slime-producing and two minor biotypes of Leuconostoc-like bacteria, all identified as Leuconostoc mesenteroides by 16S rRNA sequencing, dominated the LAB association (76.7%), which also included four subdominant Carnobacterium maltaromaticum biotypes (10.9%), one Leuconostoc lactis biotype (3.3%) and few Lactococcus (1.6%), mesophilic Lactobacillus (0.8%) and Enterococcus (0.8%). Growth and distribution of LAB and Gram-negative species were strongly batch-dependent and plant-dependent. The CEntE neither retarded growth nor altered the whey cheese spoilage association but enhanced LAB growth and the declines of Gram-negative bacteria by late storage.

In Vitro antibacterial activity of lactic acid bacteria isolated from goat’s raw milk of Mostaganem (West Algeria) against Gram negative bacteria responsible for urinary tract infections

2016 ◽  
Vol 6 (1) ◽  
pp. 15-22
Author(s):  
Zergoug Amina ◽  
Cheriguene Abderrahim ◽  
Chougrani Fadela
Keyword(s):  
Antibacterial Activity ◽  
Lactic Acid ◽  
Urinary Tract ◽  
Lactic Acid Bacteria ◽  
Raw Milk ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Tract Infections ◽  
West Algeria

Urinary tract infections (UTI) are a serious bacterial pathological challenges all over the world, leading to respiratory infections, that’s why new strategies don’t cease to develop. Lactic acid bacteria having shown beneficial effects for years in various areas, may prove to be excellent candidates in medical field. The current research focused on the selection of lactic acid bacteria having the potential of an antibacterial activity against Gram negative bacteria responsible for UTI, for an eventual use as a therapeutic agent. A total of 40 isolates were isolated from goat’s raw milk of Mostaganem (West Algeria). In vitro tests were conducted in order to determine the efficiency of the isolates to produce antibacterial agents in interaction with uropathogens. Among 40 isolates, only 10 isolates identified as Lactobacilli and Lactococci were performant. The Screening showed that the inhibitor agent was proteinaceous substance. Therfore, it is noted that a treatment with presence of LAB is very encouraging as a result of the production of bacteriocin-like substance. On the other hand, LAB can be considered as a good alter-native to the large extent to the antibiotics in the treatment of UTI.

Method of Applying Sanitizers and Sample Preparation Affects Recovery of Native Microflora and Salmonella on Whole Cantaloupe Surfaces†

2004 ◽  
Vol 67 (5) ◽  
pp. 999-1004 ◽  
Author(s):  
DIKE O. UKUKU ◽  
WILLIAM F. FETT
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Treatment Method ◽  
Microbial Populations ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Selective Media ◽  
Selective Agar ◽  
Agar Media ◽  
Native Microflora

Standardized methods for applying sanitizer treatments to cantaloupes and for recovering surviving native microflora or Salmonella on inoculated cantaloupe after sanitizing are lacking. Accordingly, the objectives of this study were to compare four methods for applying sanitizers (dipping, dipping with rotation, dipping with agitation, and dipping with rubbing) using 200 ppm of chlorine or 5% H2O2, two recovery methods (homogenization of rind plugs in a stomacher or blender), and five selective recovery media for Salmonella. Whole cantaloupes were submerged in a cocktail of five strains of Salmonella (each at approximately 2 × 108 CFU/ml) for 10 min and allowed to dry for 1 h inside a biosafety cabinet and stored at 20° C for approximately 23 h before sanitizing. The recovery of Salmonella from whole cantaloupe without sanitizing averaged 5.09 log CFU/cm2 by blending and 4.30 log CFU/cm2 by homogenization in a stomacher for the five selective agar media. Microbial populations ( Salmonella or the indigenous aerobic mesophilic bacteria, gram-negative bacteria, lactic acid bacteria, Pseudomonas spp., and yeast and mold) were not significantly (P > 0.05) reduced by treating with water regardless of the treatment method used. Sanitizing with chlorine or H2O2 by dipping, with or without rotation for 2 min, also did not reduce microbial populations. However, populations of all classes of native microflora and Salmonella were significantly (P < 0.05) reduced by sanitizer treatments (2 min) applied with agitation or by rubbing. In general, sanitizer treatments applied by rubbing resulted in greater log reductions (by up to 1.7 log unit) than for treatments applied with agitation. Populations of native microflora and Salmonella recovered from cantaloupe were higher (by up to 1.8 log unit) by blending compared to homogenization in a stomacher. In most instances, selective media used did not differ significantly (P > 0.05) for recovery of Salmonella after washing treatments.

scholarly journals 1018. Bacterial Bioburden Characterization of Infected Diabetic Foot Ulcers in Hospitalized Patients in Association with Clinical Outcomes: Traditional Cultures vs. Molecular Sequencing Methods

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S599-S600
Author(s):  
Hadar Mudrik-Zohar ◽  
Shaqed Carasso ◽  
Tal Gefen ◽  
Anat Zalmanovich ◽  
Michal Katzir ◽  
...  
Keyword(s):  
16S Rrna ◽  
Clinical Outcomes ◽  
16S Rrna Sequencing ◽  
Gram Negative Bacteria ◽  
Metagenomic Sequencing ◽  
Gram Negative ◽  
Rrna Sequencing ◽  
Traditional Cultures ◽  
Molecular Sequencing ◽  
Toe Amputation

Abstract Background Infected diabetic foot ulcers (IDFU) are a major complication of diabetes mellitus. These potentially limb-threatening ulcers are challenging to treat due to the impairment of wound healing in diabetic patients and the complex microbial environment characterizing these ulcers. Our aim was to analyze the microbiome of IDFU in association with clinical outcomes. Methods Wound biopsies from IDFU were obtained from hospitalized patients and were analyzed using traditional microbiology cultures, 16S rRNA sequencing and shotgun metagenomic sequencing. Patients’ characteristics, culture-based results and sequencing data were analyzed in association with clinical outcomes. Study Design Results 31 patients were enrolled. Significantly more anaerobic and Gram-negative bacteria were detected with sequencing methods compared to conventional cultures (59% and 76% were anaerobes according to 16SrRNA and metagenomic respectively vs. 26% in cultures, p=0.001, and 79%, 59% and 54% were Gram negative bacteria respectively, p< 0.001). Culture-based results showed that Staphylococcus aureus was more prevalent among patients who were conservatively treated (p=0.048). In metagenomic analysis the Bacteroides genus was more prevalent among patients who underwent toe amputation (p< 0.001). Analysis of metagenomic-based functional data showed that antibiotic resistance genes and genes related to biofilm production and to bacterial virulent factors were more prevalent in IDFU that resulted in toe amputation (p< 0.001). Occurrences and mean relative abundances of the most prevalent bacteria of IDFU Comparison between [A] traditional cultures, 16S rRNA sequencing and metagenomic sequencing results (genera level - 12 samples) [B] traditional cultures and metagenomic sequencing results (species level – 30 samples) [C] traditional cultures and 16S rRNA sequencing results (genera level - 30 samples) CUL – cultures; 16S - 16S rRNA sequencing; MTG – metagenomic sequencing Bacteroides genus association with toe amputation Bacteroides genera was more common among samples of patients who underwent toe amputation compared with samples of patients who were conservatively treated (p < 0.001). Species level analysis showed that Bacteroides fragilis and Bacteroides xylanisolvens predominated IDFU of patients who underwent toe amputation (p=0.04, p=0.002 respectively). No – conservative treatment; Yes – toe amputation. Functional genes differentiating patients who underwent toe amputation from conservatively treated Yellow stars – indicate genes that were associated with bacterial virulent factors, biofilm formation and resistant mechanisms – all were more prevalent in patients who underwent toe amputation (with p values<> Conclusion Molecular sequencing tools uncover the complex biodiversity of IDFU and emphasize the high prevalence of anaerobes and Gram-negative bacteria in these ulcers. Furthermore, sequencing results highlighted the possible association between certain genera, species, and bacterial functional genes to clinical outcomes Disclosures Yossi Paitan, PhD, Ilex Medical Ltd (Employee, Other Financial or Material Support, As of 01.01.2021 I am the Laboratories Manager of Ilex Labs)

scholarly journals Bryndza cheese of Slovak origin as potential resources of probiotic bacteria

10.5219/1413 ◽  
2020 ◽  
Vol 14 ◽  
pp. 641-646
Author(s):  
Miroslava Kačániová ◽  
Petra Borotová ◽  
Margarita Terenjeva ◽  
Simona Kunová ◽  
Soňa Felsöciová ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Klebsiella Pneumoniae ◽  
Enterococcus Faecalis ◽  
Yersinia Enterocolitica ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

Bryndza cheese includes several predominant lactic acid bacteria. The aim of our study was the antagonistic effect of lactic acid bacteria supernatant isolated from ewes´ cheese bryndza against ten Gram-positive and Gram-negative bacteria. Isolated strains of bacteria were obtained from bryndza which were produced in five different regions of Slovakia. Isolated strains of lactic acid bacteria were identified with mass spectrometry MALDI-TOF MS Biotyper. A total of one hundred and thirty lactic bacteria include Enterococcus faecalis, Enterococcus faecium, Enterococcus hirae, Lactobacillus brevis, Lactobacillus harbinensis, Lactobacillus johnsonii, Lactobacillus plantarum, Lactobacillus paracasei ssp. paracasei, Lactobacillus paraplantarum, Lactobacillus suebicus, Lactococcus lactis ssp. lactis, Lactococcus lactis, and Pediococcus acidilactici were tested in this study against Gram-negative bacteria: Escherichia coli CCM 3988, Klebsiella pneumoniae CCM 2318, Salmonella enterica subsp. enterica CCM 3807, Shigella sonnei CCM 1373, Yersinia enterocolitica CCM 5671 and Gram-positive bacteria: Bacillus thuringiensis CCM 19, Enterococcus faecalis CCM 4224, Listeria monocytogenes CCM 4699, Staphylococcus aureus subsp. aureus CCM 2461, Streptococcus pneumonia CCM 4501 with agar diffusion method. Lactic acid bacteria showed activity 92% against Yersinia enterocolitica, 91% against Klebsiella pneumoniae, 88% against Escherichia coli, 84% against Listeria monocytogenes. The most effective bacteria against Gram-positive and Gram-negative bacteria tested was Lactobacillus paracasei ssp. paracasei.

Microbicidal Activity of Tripotassium Phosphate and Fatty Acids toward Spoilage and Pathogenic Bacteria Associated with Poultry†

2005 ◽  
Vol 68 (7) ◽  
pp. 1462-1466 ◽  
Author(s):  
ARTHUR HINTON ◽  
KIMBERLY D. INGRAM
Keyword(s):  
Fatty Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Pathogenic Bacteria ◽  
Bacterial Flora ◽  
Aerobic Bacteria ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Microbicidal Activity ◽  
E Coli

The ability of solutions of tripotassium phosphate (TPP) and fatty acids (lauric and myristic acids) to reduce populations of spoilage and pathogenic microorganisms associated with processed poultry was examined. In vitro studies were conducted with cultures of bacteria (Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, and Staphylococcus aureus) and yeasts (Candida ernobii and Yarrowia lipolytica). Cultures of the bacteria and yeasts were suspended in solutions of TPP or mixtures of TPP with lauric or myristic acid and mixed for 5 min. Viable numbers (log CFU per milliliter) in the suspensions were enumerated on microbiological agar. Results indicated that TPP solutions are highly bactericidal toward gram-negative bacteria and that mixtures of TPP and fatty acids are highly microbicidal toward gram-negative bacteria, gram-positive bacteria, and yeasts. The microbicidal activity of mixtures of TPP and fatty acids toward the native bacterial flora of skin of processed broiler carcasses was also examined. Skin samples were washed in mixtures of TPP and fatty acid, and the populations of total aerobic bacteria, campylobacters, enterococci, E. coli, lactic acid bacteria, pseudomonads, staphylococci, and yeasts in the skin rinsates were enumerated on the appropriate microbiological media. Results indicated that washing the skin in mixtures of TPP and fatty acids produced significant reductions in the number of aerobic bacteria, campylobacters, E. coli, pseudomonads, and yeasts recovered from skin rinsates, but there was no significant reduction in the populations of enterococci, lactic acid bacteria, or staphylococci. These findings indicate that mixtures of TPP and fatty acids possess microbicidal activity against several microorganisms associated with processed poultry and that these solutions could be useful as microbicides to reduce the populations of some bacteria and yeasts associated with some poultry processing operations.

scholarly journals Biotransformation of Flavonoids by Newly Isolated and Characterized Lactobacillus pentosus NGI01 Strain from Kimchi

2021 ◽  
Vol 9 (5) ◽  
pp. 1075
Author(s):  
Chan-Mi Park ◽  
Gyoung-Min Kim ◽  
Gun-Su Cha
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
16S Rrna Sequencing ◽  
Sequencing Analysis ◽  
Lactobacillus Pentosus ◽  
Flavonoid Aglycones ◽  
Food Industries ◽  
Rrna Sequencing ◽  
16S Rrna Sequencing Analysis

Lactic acid bacteria (LAB) are generally recognized as safe (GRAS) microorganisms. This study aimed to identify novel LAB strains that can transform flavonoids into aglycones to improve bioavailability. We isolated 34 LAB strains from kimchi. The biotransformation activity of these 34 LAB strains was investigated based on α-L-rhamnosidase and β-D-glucosidase activities. Among them, 10 LAB strains with high activities were identified by 16S rRNA sequencing analysis. All tested LAB strains converted hesperidin to hesperetin (12.5–30.3%). Of these, only the Lactobacillus pentosus NGI01 strain produced quercetin from rutin (3.9%). The optimal biotransformation conditions for the L. pentosus NGI01 producing hesperetin and quercetin were investigated. The highest final product concentrations of hesperetin and quercetin were 207 and 78 μM, respectively. Thus, the L. pentosus NGI01 strain can be a biocatalyst for producing flavonoid aglycones in the chemical and food industries.

scholarly journals Microbiota of an Italian Grana-Like Cheese during Manufacture and Ripening, Unraveled by 16S rRNA-Based Approaches

2016 ◽  
Vol 82 (13) ◽  
pp. 3988-3995 ◽  
Author(s):  
Valentina Alessandria ◽  
Ilario Ferrocino ◽  
Francesca De Filippis ◽  
Mauro Fontana ◽  
Kalliopi Rantsiou ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
16S Rrna ◽  
Raw Milk ◽  
Lactobacillus Delbrueckii ◽  
Microbiota Composition ◽  
Rt Pcr ◽  
Content Type ◽  
Spoilage Bacteria

ABSTRACTThe microbial ecology of cheese involves a rich and complex interaction between starter lactic acid bacteria and nonstarter lactic acid bacteria (NSLAB), mainly originating from raw milk and/or from the environment, that can contribute to the final characteristics of cheese. The aim of the present research was the exploration of the active microbiota by RNA-based approaches during the manufacturing and ripening of a Grana-like cheese. Reverse transcriptase PCR (RT-PCR)-denaturing gradient gel electrophoresis (DGGE) and RNA-based high-throughput sequencing were applied to profile microbial populations, while the enumeration of active bacteria was carried out by using quantitative PCR (qPCR). Three different cheese productions (named D, E, and F) collected in the same month from the same dairy plant were analyzed. The application of the qPCR protocol revealed the presence of 7 log CFU/ml of bacterial load in raw milk, while, during ripening, active bacterial populations ranged from <4 to 8 log CFU/ml. The natural whey starters used in the three productions showed the same microbiota composition, characterized by the presence ofLactobacillus helveticusandLactobacillus delbrueckii. Nevertheless, beta-diversity analysis of the 16S rRNA sequencing data and RT-PCR-DGGE showed a clear clustering of the samples according to the three productions, probably driven by the different milks used. Milk samples were found to be characterized by the presence of several contaminants, such asPropionibacterium acnes,Acidovorax,Acinetobacter,Pseudomonas, and NSLAB. The core genera of the starter tended to limit the development of the spoilage bacteria only in two of the three batches. This study underlines the influence of different factors that can affect the final microbiota composition of the artisanal cheese.IMPORTANCEThis study highlights the importance of the quality of the raw milk in the production of a hard cheese. Independent from the use of a starter culture, raw milk with low microbiological quality can negatively affect the populations of lactic acid bacteria and, as a consequence, impact the quality of the final product due to metabolic processes associated with spoilage bacteria.

Sign in / Sign up

Export Citation Format

Share Document