Inactivation of Calcium-Dependent Lactic Acid Bacteria Phages by Phosphates

2007 ◽  
Vol 70 (6) ◽  
pp. 1518-1522 ◽  
Author(s):  
V. B. SUÁREZ ◽  
M. L. CAPRA ◽  
M. RIVERA ◽  
J. A. REINHEIMER

The capacity of three phosphates to interrupt the lytic cycle of four specific autochthonal bacteriophages of lactic acid bacteria used as starters was assayed. The phosphates used (polyphosphates A and B and sodium tripolyphosphate–high solubility [TAS]) were selected on the basis of their capacity to sequester divalent cations, which are involved in the lytic cycle of certain bacteriophages. The assays were performed in culture media (deMan Rogosa Sharpe and Elliker broths) and reconstituted (10%, wt/vol) commercial skim milk to which phosphates had been added at concentrations of 0.1, 0.3, and 0.5% (wt/vol). Phosphate TAS was the most inhibitory one, since it was able to inhibit the lytic cycle of all bacteriophages studied, in both broths and milk. In broth, polyphosphates A and B inhibited the lytic cycle of only two bacteriophages at the maximal concentration used (0.5%), whereas in milk, they were not capable of maintaining the same inhibitory effect.

2007 ◽  
Vol 74 (4) ◽  
pp. 387-391 ◽  
Author(s):  
Maria BT Ortolani ◽  
Gabriela N Viçosa ◽  
Vanerli Beloti ◽  
Luís A Nero

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.


2013 ◽  
Vol 42 (6) ◽  
pp. 991-995 ◽  
Author(s):  
So-Lim Park ◽  
Sunhyun Park ◽  
Jieun Jang ◽  
Hye-Jung Yang ◽  
Sung-Won Moon ◽  
...  

LWT ◽  
2001 ◽  
Vol 34 (4) ◽  
pp. 239-243 ◽  
Author(s):  
Erika Trauth ◽  
Jean-Paul Lemaı̂tre ◽  
Christine Rojas ◽  
Charles Diviès ◽  
Rémy Cachon

Life ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 268
Author(s):  
Wei-Kuang Lai ◽  
Ying-Chen Lu ◽  
Chun-Ren Hsieh ◽  
Chien-Kei Wei ◽  
Yi-Hong Tsai ◽  
...  

Lactic acid bacteria have functions in immunoregulation, antagonism, and pathogen inhibition. The purpose of this study was to evaluate the effectiveness of lactic acid bacteria (LAB) in countering oral pathogens and develop related products. After a series of assays to 450 LAB strains, 8 heat-inactivated strains showed a strong inhibitory effect on a caries pathogen, Streptococcus mutans, and 308 heat-inactivated LAB strains showed a strong inhibitory effect on a periodontal pathogen, Porphyromonas gingivalis. The key reasons for inhibiting oral pathogens were bacteriocins produced by LAB and the coaggregation effect of the inactivated cells. We selected Lacticaseibacillus (Lb) paracasei 111 and Lb.paracasei 141, which had the strongest inhibitory effects on the above pathogens, was the main oral health food source. The optimal cultural conditions of Lb. paracasei 111 and Lb. paracasei 141 were studied. An oral tablet with a shelf life of 446 days made of the above strains was developed. A 40 volunteers’ clinical study (CSMUH IRB number: CS05065) was conducted with this tablet in the Periodontological Department of the Stomatology Research Center, Affiliated Hospital of Chung Shan Medical University (Taiwan). After 8 weeks of testing, 95% and 78.9% of patients showed an effect on reducing periodontal pathogens and improving probing pocket depth, respectively, in the oral tablet group.


2021 ◽  
Vol 51 (2) ◽  
Author(s):  
Fernanda Cristina Kandalski Bortolotto ◽  
Maria Helena da Rosa Farfan ◽  
Nathalia Cristina Kleinke Jede ◽  
Gabriela Maia Danielski ◽  
Renata Ernlund Freitas de Macedo

ABSTRACT: Sausages are highly susceptible to microbial spoilage. Lactic acid bacteria (LAB) is the main group of spoilage bacteria in vacuum packed cooked sausages. To control microbial growth natural antimicrobials have been used as food preservatives. The aim of this study was to identify strains of lactic acid bacteria isolated from spoiled commercial Calabresa sausages and use them in an in vitro challenge with the natural antimicrobials, nisin (NI) and ε-poly-L-lysine (ε-PL). Mass spectrometry identification of LAB isolated from sausages using MALDI-TOF revealed a predominance of L. plantarum in the LAB population. RAPD-PCR of L. plantarum strains showed four different genetic profiles. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of NI and ε-PL, alone and in combination, against a pool of different profiles L. plantarum were determined. MIC of NI and ε-PL were 0.468 mg/ L and 75 mg/ L; respectively, whereas MBC of NI and ε-PL were 12.48 mg/L and 150 mg/L, respectively. The combined effect of NI and ε-PL was determined using concentrations at 1/4 and 1/8 of individual MICs. Synergistic effect was confirmed at both concentrations showing a fractional inhibitory concentration index of 0.5 and 0.2, respectively. The combination of NI and ε-PL at a small concentration of 0.05 mg/L and 9.375 mg/L, respectively, showed inhibitory effect towards spoilage L. plantarum Results show the potential of the combined use of NI and ε-PL to control sausage spoilage-associated with lactobacilli.


2015 ◽  
Vol 12 (3) ◽  
pp. 479-484
Author(s):  
Baghdad Science Journal

In this study Candida speices was diagnosed in 26 swab samples from patients with denture stomatitis , investigates the antagonism activity of Lactobacillus was investigated against the yeast of Candida albicans in vitro.Results revealed that The inhibition effect of Lactic Acid Bacteria against C.albicans was examined in solid medium, L.plantarum gave higher inhibition average 11mm followed by L.acidophillus with average 9 mm and, L.fermentum , L.casei with averages 7 mm. Whereas the filtrates, the highest inhibition zone were 20 and 16 mm by L. plantarum and L.acidophillus, respectively.


2011 ◽  
Vol 74 (4) ◽  
pp. 631-635 ◽  
Author(s):  
VASILIKI A. BLANA ◽  
AGAPI I. DOULGERAKI ◽  
GEORGE-JOHN E. NYCHAS

Fifteen fingerprints (assigned to Leuconostoc spp., Leuconostoc mesenteroides, Weissella viridescens, Leuconostoc citreum, and Lactobacillus sakei) of 89 lactic acid bacteria (LAB) isolated from minced beef stored under modified atmospheres at various temperatures were screened for their ability to exhibit autoinducer-2 (AI-2)–like activity under certain growth conditions. Cell-free meat extracts (CFME) were collected at the same time as the LAB isolates and tested for the presence of AI-2–like molecules. All bioassays were conducted using the Vibrio harveyi BAA-1117 (sensor 1−, sensor 2+) biosensor strain. The possible inhibitory effect of meat extracts on the activity of the biosensor strain was also evaluated. AI-2–like activity was observed for Leuconostoc spp. isolates, but none of the L. sakei strains produced detectable AI-2–like activity. The AI-2–like activity was evident mainly associated with the Leuconostoc sp. B 233 strain, which was the dominant isolate recovered from storage at 10 and 15°C and at the initial and middle stages of storage at chill temperatures (0 and 5°C). The tested CFME samples displayed low AI-2–like activity and inhibited AI-2 activity regardless of the indigenous bacterial populations. The LAB isolated during meat spoilage exhibited AI-2–like activity, whereas the LAB strains retrieved depended on storage time and temperature. The production of AI-2–like molecules may affect the dominance of different bacterial strains during storage. The results provide a basis for further research concerning the effect of storage temperature on the expression of genes encoding AI-2 activity and on the diversity of the ephemeral bacterial population.


10.5219/1604 ◽  
2021 ◽  
Vol 15 ◽  
pp. 995-1004
Author(s):  
Aleš Vavřiník ◽  
Kateřina Štůsková ◽  
Adrian Alumbro ◽  
Methusela Perrocha ◽  
Lenka Sochorová ◽  
...  

The presented work aimed to study the inhibition using nanoparticles produced by the green synthesis in selected acetic acid and lactic acid bacteria, which are related to viticulture. The degree of ability to eliminate silver particles produced by green syntheses was determined using the plate method on Petri dishes. This is done using two different approaches - the method of direct application of the solution to the surface of the inoculated medium (determination of inhibition zones) and the method of application using nanoparticles to the inoculated medium. Gluconobacter oxydans (CCM 3618) and Acetobacter aceti (CCM 3620T) were studied from acet acetic bacteria. The lactic acid bacteria were Lactobacillus brevis (CCM 1815) and Pediococcus damnosus (CCM 2465). The application of silver nanoparticles was always in concentrations of 0, 0.0625, 0.125, 0.25, 0.5, and 1 g.L-1. All applied concentrations of silver nanoparticles showed an inhibitory effect on the monitored microorganisms. Silver particles could be used in wine technology for their antibacterial effects, mainly to inhibit microorganisms during vinification, as a substitute for sulfur dioxide.


1988 ◽  
Vol 51 (8) ◽  
pp. 600-606 ◽  
Author(s):  
MICHELLE M. SCHAACK ◽  
ELMER H. MARTH

The ability of Listeria monocytogenes to grow and compete with mesophilic lactic acid bacteria was examined. Autoclaved skim milk was inoculated with 103 cells of L. monocytogenes (strain V7 or Ohio)/ml, and with 5.0, 1.0, 0.5 or 0.1% of a milk culture of either Streptococcus cremoris or Streptococcus lactis. Inoculated milks were fermented for 15 h at 21 or 30°C, followed by refrigeration at 4°C. Samples were plated on McBride Listeria Agar to enumerate L. monocytogenes and on either APT Agar or plate count agar to enumerate lactic acid bacteria. L. monocytogenes survived in all fermentations, and commonly also grew to some extent. Incubation at 30°C with 5% S. lactis as inoculum appeared to be the most inhibitory combination for strain V7, causing 100% inhibition in growth based on maximum population attained. S. cremoris at the 5.0% and 0.1% inoculum levels, was slightly less inhibitory to L. monocytogenes at 37°C, but it was slightly more inhibitory to L. monocytogenes at the 1.0% inoculum level than was S. lactis. In general, S. lactis reduced the pH of fermented milks more than did S. cremoris. The population of L. monocytogenes began to decrease before 15 h in only one test combination, which was use of a 5.0% inoculum of S. cremoris and 30°C incubation. In most instances, growth of the pathogen appeared to be completely inhibited when the pH dropped below 4.75.


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