618. Host-phage relationship of cheese starter organisms: I. Interaction of phage races with a strain of Streptococcus lactis and its lysogenic and resistant derivatives

1956 ◽  
Vol 23 (1) ◽  
pp. 120-125 ◽  
Author(s):  
J. Czulak ◽  
Jill Naylor
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Strain ◽  
Acquired Resistance ◽  
Secondary Growth ◽  
The Other ◽  
Physiological Changes ◽  
Streptococcus Lactis ◽  
Lysogenic Culture ◽  
Relationship Of

A lysogenic culture, prepared in the laboratory from a strain of Streptococcus lactis, was used as a cheese starter in commercial factories. It was attacked in turn by two other unrelated phage races. The lysogenic condition, which involved slight morphological and physiological changes, persisted in the subsequent forms resistant to one or both the new phage races. Acquired resistance to any one of the three phages did not protect the culture from the other two phages.In nature such interactions between phage races and lactic acid bacteria must be constantly taking place, giving rise to similarly related strains.Two of the three phage races produced spreading haloes around their plaques due to a lysin released during phage action. The lysin may also interfere with the survival of secondary growth after attack by these phage races. Production of this type of lysin is thus a property of the phage race and not of the bacterial strain.

scholarly journals Hardening Properties of Cheeses by Latilactobacillus curvatus PD1 Isolated from Hardened Cheese-Ddukbokki Rice Cake

2021 ◽  
Vol 9 (5) ◽  
pp. 1044
Author(s):  
Jeong A Kim ◽  
Geun Su Kim ◽  
Se Mi Choi ◽  
Myeong Seon Kim ◽  
Do Young Kwon ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acid Production ◽  
Lactobacillus Casei ◽  
Leuconostoc Mesenteroides ◽  
The Other ◽  
Rice Cake ◽  
Two Samples ◽  
High Protease Activity

Hardening of cheese is one of major issues that degrade the quality of Home Meal Replacement (HMR) foods containing cheese such as Cheese-ddukbokki rice cake (CD, stir-fried rice cakes with shredded cheese). The quality of cheese, such as pH, proteolytic, and flavor properties, depends on various lactic acid bacteria (LAB) used in cheese fermentation. The hardening of cheese is also caused by LAB. In this study, various LAB strains were isolated from CD samples that showed rapid hardening. The correlation of LAB with the hardening of cheese was investigated. Seven of the CD samples with different manufacturing dates were collected and tested for hardening properties of cheese. Among them, strong-hardening of cheese was confirmed for two samples and weak-hardening was confirmed for one sample. All LAB in two strong-hardening samples and 40% of LAB in one weak-hardening sample were identified as Latilactobacillus curvatus. On the other hand, most LAB in normal cheese samples were identified as Leuconostoc mesenteroides and Lactobacillus casei. We prepared cheese samples in which L. curvatus (LC-CD) and L. mesenteroides (LM-CD) were most dominant, respectively. Each CD made of the prepared cheese was subjected to quality test for 50 days at 10 °C. Hardening of cheese with LC-CD dominant appeared at 30 days. However, hardening of cheese with LM-CD dominant did not appear until 50 days. The pH of the LC-CD was 5.18 ± 0.04 at 30 days, lower than that of LM-CD. The proteolytic activity of LC-CD sample was 2993.67 ± 246.17 units/g, higher than that of LM-CD sample (1421.67 ± 174.5 units/g). These results indicate that high acid production and high protease activity of L. curvatus might have caused hardening of cheese.

Characterization of bacteria and antibiotic resistance in commercially-produced cheeses sold in China

2021 ◽  
Author(s):  
Jinghui Yao ◽  
Jing Gao ◽  
Jianming Guo ◽  
Hengan Wang ◽  
En Zhang ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acquired Resistance ◽  
Antibiotic Resistance Genes ◽  
16S Rrna Gene Sequencing ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Rrna Gene ◽  
Rrna Gene Sequencing

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.

Behavior of Listeria monocytogenes in Skim Milk during Fermentation with Mesophilic Lactic Starter Cultures

1988 ◽  
Vol 51 (8) ◽  
pp. 600-606 ◽  
Author(s):  
MICHELLE M. SCHAACK ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Skim Milk ◽  
Starter Cultures ◽  
Plate Count ◽  
Inoculum Level ◽  
Plate Count Agar ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris

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.

Detection by Warburg manometry of compounds stimulatory to lactic acid bacteria

1982 ◽  
Vol 49 (3) ◽  
pp. 479-486 ◽  
Author(s):  
Leslie E. Webb
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Scenedesmus Obliquus ◽  
Test Organism ◽  
Rapid Test ◽  
Lag Phase ◽  
Streptococcus Lactis ◽  
Manometric Method ◽  
Strain Dependent ◽  
Stimulation Of

SUMMARYThe effect of aqueous algal extract, yeast extract casein peptone and meat peptone on acid production by 4 strains of lactic acid bacteria was tested manometrically using a milk–bicarbonate medium. A strain-dependent stimulation of the bacteria was detected after 4 h incubation. After fractionation of an aqueous extract of the green algaScenedesmus obliquuson a Sephadex G25 column, 2 fractions with stimulatory activity were found usingStreptococcus lactisas the test organism. One of the peaks of activity, confined to shortening of the lag phase, was due to hypoxanthine which, however, had only a slight stimulatory effect in conventional milk souring tests. The manometric method provides a sensitive and rapid test for detecting compounds with biological activity in µg amounts, but it should be accompanied by milk souring tests for interpretation of the type of stimulation involved.

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 Role of Plasmids in Lactobacillus brevis BSO 464 Hop Tolerance and Beer Spoilage

2014 ◽  
Vol 81 (4) ◽  
pp. 1234-1241 ◽  
Author(s):  
Jordyn Bergsveinson ◽  
Nina Baecker ◽  
Vanessa Pittet ◽  
Barry Ziola
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Brevis ◽  
The Other ◽  
Plasmid Curing ◽  
Content Type ◽  
Dramatic Effect ◽  
Plasmid Loss ◽  
Beer Spoilage

ABSTRACTSpecific isolates of lactic acid bacteria (LAB) can grow in the harsh beer environment, thus posing a threat to brew quality and the economic success of breweries worldwide. Plasmid-localized genes, such ashorA,horC, andhitA, have been suggested to confer hop tolerance, a trait required for LAB survival in beer. The presence and expression of these genes among LAB, however, do not universally correlate with the ability to grow in beer. Genome sequencing of the virulent beer spoilage organismLactobacillus brevisBSO 464 revealed the presence of eight plasmids, with plasmids 1, 2, and 3 containinghorA,horC, andhitA, respectively. To investigate the roles that these and the other five plasmids play inL. brevisBSO 464 growth in beer, plasmid curing with novobiocin was used to derive 10 plasmid variants. Multiplex PCRs were utilized to determine the presence or absence of each plasmid, and how plasmid loss affected hop tolerance and growth in degassed (noncarbonated) beer was assessed. Loss of three of the eight plasmids was found to affect hop tolerance and growth in beer. Loss of plasmid 2 (horCand 28 other genes) had the most dramatic effect, with loss of plasmid 4 (120 genes) and plasmid 8 (47 genes) having significant, but smaller, impacts. These results support the contention that genes on mobile genetic elements are essential for bacterial growth in beer and that beer spoilage ability is not dependent solely on the three previously described hop tolerance genes or on the chromosome of a beer spoilage LAB isolate.

scholarly journals Isolation and Identification of Microorganisms Including Lactic Acid Bacteria and Their Use in Microbial Deacidification of Wines from Domestic Vineyards

2013 ◽  
Vol 62 (3) ◽  
pp. 331-334
Author(s):  
IWONA DROŻDŻ ◽  
MAŁGORZATA MAKAREWICZ ◽  
TADEUSZ TUSZYŃSKI
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Acidophilus ◽  
Oenococcus Oeni ◽  
Lactobacillus Delbrueckii ◽  
The Other ◽  
Total Acidity ◽  
Isolation And Identification ◽  
Volatile Acidity ◽  
Other Hand

The aim of this study was to identify various bacteria isolated from grapes and their wines. Additionally we investigated the capacity of lactic acid bacteria for microbiological deacidification of wines produced in Poland. We have identified Oenococcus oeni, Lactobacillus acidophilus and Lactobacillus delbrueckii. During the microbial deacidification process, we observed decreases of total acidity and increases of volatile acidity, with statistically significant changes noted for O. oeni in Marechal Foch and Seyval Blanc, and for Lb. acidophilus in Frontenac. On the other hand, a statistically significant increase in pH was observed in Marechal Foch and Seyval Blanc following deacidification by O. oeni.

scholarly journals Antioxidant Activity, Fiber, Acidity (pH), and Population of Lactic Acid Bacteria in Green Juice as Functional Beverages

2020 ◽  
Vol 2 ◽  
pp. 00005
Author(s):  
Ni Wayan Nursini ◽  
Komang Lina Venti ◽  
I Gusti Ayu Wita
Keyword(s):  
Antioxidant Activity ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gravimetric Method ◽  
The Other ◽  
Crude Fiber ◽  
Plate Method ◽  
Dpph Method ◽  
Functional Beverages ◽  
Β Carotene

<p><span style="line-height: 107%;">Bok choy (<i>Brassica rapa </i>L) is a vegetable group of <i>Brassicaceae </i>which still a family with Chinese vegetables. It contains phytochemical substances such as carotenoids, </span><span lang="EN" style="line-height: 107%;">β-carotene</span><span style="line-height: 107%;">, and glucosinolates which are a source of antioxidant. Bok choy can be processed into juice. The purpose of this research is to determine the content of the antioxidant activity, fiber, acidity (pH) and population of lactic acid bacteria in each formulation. The other ingredients added in making this green juice are yogurt and honey made into 5 formulations. The analysis of this research was the analysis of antioxidant activity content using DPPH method (2.2, -diphenyl-1- picrylhydrazyl), crude fiber contents analysis using gravimetric method, pH analysis using pH meter and analysis of lactic acid bacteria using spread plate method. The result obtained is the highest content of the antioxidant activity was found in formulation 5 consist of 30 g yogurt, 15 g honey and 50 g bok choy with 35,198 ± 0,057%. The content of crude fiber ranged from (0,447 ± 0,046) g to (0,507 ± 0,058) g. The highest of acidity (pH) is in formulation 1 which consists of 10 g of yogurt, 15 g of honey and 50 g of bok choy at 5,50 ± 0,040. The highest population content of lactic acid bacteria in formulation 5 consists of 30 g yogurt, 15 g honey and 50 g bok choy at 2,8 x 106cfu/mL. Therefore, green juice can be used as functional drinks.</span><br> </p>

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