Behavior of Listeria monocytogenes in Skim Milk and in Yogurt Mix during Fermentation by Thermophilic Lactic Acid Bacteria

1988 ◽  
Vol 51 (8) ◽  
pp. 607-614 ◽  
Author(s):  
MICHELLE M. SCHAACK ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Skim Milk ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Inhibition Of Growth ◽  
Order Of Magnitude ◽  
Thermophilic Lactic Acid Bacteria

Behavior of Listeria monocytogenes in skim milk and in yogurt mix during fermentation with thermophilic lactic starters was determined. Sterile skim milk was inoculated with ca. 103 L. monocytogenes cells/ml and with 5.0, 1.0 or 0.1% of a milk culture of Streptococcus thermophilus, Lactobacillus bulgaricus or a mixture of the two species. The milk was incubated at 37 or 42°C for 15 h, followed by refrigeration at 4°C. Yogurt mix was inoculated with ca. 5 × 103 L. monocytogenes cells/ml of mix and then was incubated at 45°C for 5 h, followed by refrigeration at 4°C. L. monocytogenes survived the 15-h fermentation with S. thermophilus in all combinations of level of inoculum and temperature of incubation, but inhibition of growth ranged from 96 to 100%. When incubated with L. bulgaricus, L. monocytogenes survived only between 9 and 15 h of incubation; a decrease in pH to below 4.0 was accompanied by rapid death of the pathogen. The combination of the two species was more inhibitory to L. monocytogenes than was S. thermophilus alone but less inhibitory than was L. bulgaricus alone. In yogurt mix, L. monocytogenes grew during the fermentation and increased in number by about one order of magnitude.

scholarly journals PENGARUH PENGGUNAAN MADU TERHADAP NILAI pH, SINERESIS, DAN TOTAL BAKTERI ASAM LAKTAT YOGHURT SINBIOTIK

ZOOTEC ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 214
Author(s):  
Reynaldi Baguna ◽  
A. Yelnetty ◽  
S.E. Siswosubroto ◽  
N. Lontaan
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Ph Value ◽  
Skim Milk ◽  
Animal Husbandry ◽  
Streptococcus Thermophilus ◽  
Test Tube ◽  
Lactobacillus Bulgaricus ◽  
Animal Product ◽  
Randomized Design

THE EFFECT OF THE ADDITION OF HONEY TO THE PH VALUE, SYNERESIS AND TOTAL LACTIC ACID BACTERIA OF SINBIOTIK YOGURT. This study was conducted to determine whether honey gives an influence on the pH value, syneresis and LAB of synbiotic yogurt. In this study, the main ingredients used were 5 liters UHT milk, Skim milk 400 g, honey 240 mL, Lactobacillus acidophillus bacteria, Streptococcus thermophilus and Lactobacillus bulgaricus, aqudes, MRS Media (Man Rogosa Sharpe Medium). Equipment used during the study included autoclave, pH meter, Erlenmeyer, test tube, pipette, thermometer, analytical scale, petri dishe, desiccator, blender, oven, incubator, micro pipette, burette, spritus lamp, goblet, refrigerator. This research was carried out on January 7 2019 until March 12 2019 at the Laboratory of Animal Product Technology Faculty of Animal Husbandry, Sam Ratulangi University, Manado. The experimental design used in this study was a Completely Randomized Design (CRD) method with treatments 5 and 4 replications. The variables analyzed in this study are pH, Sinereis and Total LAB. The data obtained were analyzed using ANOVA, there were significant differences between the treatments followed by the BNJ test. The results of this study indicate that the treatments of P0(0%), P1(3%), P2(6%), P3(9%) and P4(12%) have a very significant effect (P <0.01) on the pH value, Sineresis and Total LAB. Based on the results and discussion that the use of honey by 12% can increase the value and produce the best pH, syneresis and total lactic acid bacteria in synbiotic yogurt.Keywords: Sinbiotic Yogurt, Honey, pH, Sinresis, LAB.

Behavior of Listeria monocytogenes in Pasteurized Milk during Fermentation with Lactic Acid Bacteria

2000 ◽  
Vol 63 (7) ◽  
pp. 916-920 ◽  
Author(s):  
WAYNE M. PITT ◽  
TERENCE J. HARDEN ◽  
RON R. HULL
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Starter Culture ◽  
Streptococcus Thermophilus ◽  
Experimental Period ◽  
Starter Cultures ◽  
Lactobacillus Bulgaricus ◽  
Pasteurized Milk ◽  
Nonstarter Lactic Acid Bacteria

The behavior of Listeria monocytogenes in pasteurized milk during fermentation with starter and nonstarter lactic acid bacteria was investigated. Pasteurized milk was co-inoculated with approximately 104 CFU/ml of L. monocytogenes and 106 CFU/ml of Lactococcus lactis, Lactococcus cremoris, Lactobacillus plantarum, Lactobacillus bulgaricus, or Streptococcus thermophilus. Inoculated milks were incubated at 30°C or 37°C for 24 to 72 h. Listeria monocytogenes survived and also grew to some extent during incubation in the presence of all starter cultures; however, inhibition ranged from 83 to 100% based on maximum cell populations. During incubation with L. bulgaricus and L. plantarum, L. monocytogenes was completely inactivated after 20 h and 64 h of incubation at 37°C and 30°C, respectively. The pH of the fermenting milks declined steadily throughout the fermentation periods and was approximately 4.2 at the conclusion of the experimental period regardless both of the starter culture and pathogen combination or the temperature of incubation.

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.

Influence of thermophilic lactic acid bacteria strains on propionibacteria growth and lactate consumption in an Emmental juice-like medium

1999 ◽  
Vol 66 (1) ◽  
pp. 105-113 ◽  
Author(s):  
ANNE THIERRY ◽  
DELPHINE SALVAT-BRUNAUD ◽  
JEAN-LOUIS MAUBOIS
Keyword(s):  
Amino Acids ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Free Amino Acids ◽  
Free Amino ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
The Media ◽  
Lactate Consumption ◽  
Thermophilic Lactic Acid Bacteria

Swiss-type cheeses such as Emmental are characterized by the successive development of thermophilic lactic acid bacteria (TLAB) and propionibacteria. The aim of this study was to determine whether the choice of TLAB strain influenced propionibacteria. TLAB and propionibacteria were cultured sequentially under the conditions prevailing in cheese. Firstly, 11 Emmental juice-like media were prepared by fermenting casein-enriched milk with pure or mixed cultures of TLAB (Lactobacillus helveticus, Lb. delbrueckii subsp. lactis and Streptococcus thermophilus), differing in their proteolytic activities. TLAB cells were then removed by microfiltration. Finally, five strains of Propionibacterium freudenreichii were grown on these media at 24°C under anaerobiosis and their growth characteristics and lactate consumption determined. The media mainly differed in their contents of peptides (1·9–5·3 g/kg) and free amino acids (1·0–5·6 g/kg) and the proportions of lactate isomers (42–92% of the L(+) isomer). Propionibacteria were significantly (P<0·05) influenced by TLAB strains (differences in doubling times of up to 20% and differences in lactate consumption after 600 h culture of up to 52%). The influence of TLAB was similar for all the propionibacteria tested, depended on the TLAB strains and could not be generalized to the TLAB species. Propionibacteria were stimulated by high peptide levels, low levels of free amino acids and NaCl, a low proportion of L(+)-lactate and other undetermined factors. However, variations due to TLAB were less than those between propionibacteria strains.

Microstructure and rheology of an acid-coagulated cheese (Karish) made with an exopolysaccharide-producing Streptococcus thermophilus strain and its exopolysaccharide non-producing genetic variant

2004 ◽  
Vol 71 (1) ◽  
pp. 116-120 ◽  
Author(s):  
Ashraf N Hassan ◽  
Milena Corredig ◽  
Joseph F Frank ◽  
Morsi Elsoda
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Physical Properties ◽  
Creep Test ◽  
Genetic Variant ◽  
Skim Milk ◽  
Streptococcus Thermophilus ◽  
Protein Network ◽  
Dynamic Rheology ◽  
Soft Acid

The objective of this research was to determine the effect of exopolysaccharide (EPS) production by lactic acid bacteria on the microstructure and rheology of Karish cheese, a soft acid coagulated cheese made using skim milk. An EPS-producing strain of Streptococcus thermophilus, and its EPS non-producing genetic variant were used to make comparable batches of the cheese. EPS in cheese was visualized by cryo-SEM as a large, dense, filamentous mass. Cheese made with the EPS non-producing culture was characterized by a dense protein network with smaller pores compared to that prepared with the EPS-producing culture. High elastic and viscous moduli measured by dynamic rheology were observed for EPS negative cheese and was attributed to its dense protein network. Creep test experiments demonstrated that cheese prepared with the EPS non-producing strain was more rigid and recovered its deformation, while cheese made using the EPS producing culture was more deformable. These results indicate that EPS-producing cultures can improve the physical properties of Karish cheese by reducing undesirable rigidity.

scholarly journals Identifying the Diversity of Dominant LABs from Fermented Dairy Products Dahi and Yoghurt in Eastern Region of Nepal

2019 ◽  
Vol 11 ◽  
pp. 60-64
Author(s):  
Sanjay Mahato ◽  
Aakash Kumar Shahani
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Eastern Region ◽  
Isolation And Identification ◽  
Carbohydrate Utilization ◽  
Variable Nature ◽  
Microbiological Techniques ◽  
Fermented Dairy

The aim of this study was to isolate and identify lactic acid bacteria diversity from dahi/ yoghurt. Curd, also known as commercially prepared yoghurt or homemade Dahi, is formed during the slow lactic fermentation of lactose from milk by thermophilic lactic acid bacteria (LAB). Thirty-five samples of yoghurt and curd were collected from the Biratnagar and isolation and identification of bacteria were done by various microbiological techniques like MRS Agar inoculation, colony characteristics, microscopic and biochemical examination. A total of sixty-six strains of lactobacilli were isolated from curd and identification of strains was done by biochemical and carbohydrate utilization test. Lactobacillus bulgaricus, L. casei, L. fermentum, L. acidophilus, and Streptococcus thermophilus were identified from curd. pH of samples was between 3.0 to 4.0 for homemade dahi; while 4.34 to 4.5 for commercially available yoghurt. The mean colony count of lactic acid bacteria was 1.4x107–4.9x107 cfu/g. 37.9% of samples contained Streptococcus thermophilus, 30.3% had Lactobacillus bulgaricus. Forty-five isolates from 24 industrial yoghurt samples showed 37.5% of the yoghurt contained both Lactobacillus bulgaricus and Streptococcus thermophilus followed by 25% samples having S. thermophilus and L. acidophilus. Other species like L. fermentum and L. casei were less common. From 11 homemade dahi samples, 54.5% of curd possessed both S. thermophilus and L. bulgaricus; 18.2% curd had both S. thermophilus and L. fermentum. The study concludes that L. bulgaricus and Streptococcus thermophilus are prevalent potent lactic acid bacteria. This study provides an account of the diversity of lactic acid bacteria in dahi/ yoghurt which will provide useful information about the variable nature of curd in this region to future researchers.

Utilization of Lesser Yam (Dioscorea esculenta L.) Flour as Prebiotic in Yogurt to Total Lactic Acid Bacteria (LAB), Sugar Reduction, and Organoleptic Properties

2020 ◽  
Vol 2 ◽  
pp. 00011
Author(s):  
Yoyok Budi Pramono ◽  
Nurwantoro Bambang Dwiloka ◽  
Sri Mulyani ◽  
Bhakti Etza Setiani ◽  
Maulida Rochmayani ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Raw Materials ◽  
Sugar Content ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Crude Fiber ◽  
Organoleptic Properties ◽  
Randomized Design ◽  
Sugar Reduction

This study aims to determine the effect of the concentration the addition of lesser yam as prebiotic to total Lactic Acid Bacteria (LAB), reducing sugar content, crude fiber, viscosity, and organoleptic properties of yogurt with a combination of three bacteria (Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus acidophilus). The design of this study used a completely randomized design (CRD) with 4 treatments and 5 replications with variations in the addition of lesser yam tuber, namely T1 with a concentration of 0%, T2 with a concentration of 2%, T3 with a concentration of 4% and T4 with a concentration of 6%. The raw materials used are pasteurized fresh cow's milk, lesser yam tuber flour, and yogurt starter. The results showed that the addition of different lesser yam tuber flour had a significant effect (P &lt;0.05) on total LAB, sugar reduction, crude fiber, viscosity, and organoleptic properties of yogurt. The ideal treatment for the addition of lesser yam tuber flour is the concentration of 2% lesser yam tuber, which produces a total LAB is 9.2 x 109, a sugar reduction is 0.653 mg/mL, crude fiber is 1.3%, 82.25 cPs, and organoleptic properties had sour taste and viscosity is rather thick which the most preferred.<br>

SURVIVAL OF SALMONELLA TYPHIMURIUM IN REFRIGERATED CULTURED MILKS1

1972 ◽  
Vol 35 (8) ◽  
pp. 489-495 ◽  
Author(s):  
H. s. Park ◽  
E. H. Marth
Keyword(s):  
Lactic Acid ◽  
Citric Acid ◽  
Lactic Acid Bacteria ◽  
Salmonella Typhimurium ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
Lactobacillus Bulgaricus ◽  
Refrigerated Storage ◽  
Streptococcus Lactis ◽  
Pure Cultures

Cultured skimmilks containing Salmonella typhimurium were prepared at 21, 30, or 42 C using different species of lactic acid bacteria (0.25, 1.0, and 5% inoculum) either singly or in combinations. Several commercial cultures also were used. Cultured skimmilks were stored at 11 C and tested at 3-day intervals for numbers of viable salmonellae and lactic acid bacteria and for pH. Survival of S. typhimurium varied from 6 to 9 days and from 3 to 6 days in milks cultured with 0.25% Streptococcus lactis at 21 and 30 C, respectively. Increasing the inoculum to 1% with incubation at 30 C yielded a product no more detrimental to S. typhimurium than when the lower inoculum was used at 30 C. Survival of S. typhimurium always exceeded 9 days when S. cremoris was used to make cultured skimmilks. Products made with commercial mixed cultures composed of S. lactis and S. cremoris allowed S. typhimurium to survive for periods intermediate between the extremes observed when pure cultures were used. Skimmilks cultured with Streptococcus diacetilactis and Leuconostoc citrovorum, even when skimmilks cultured with the latter organism were acidified with citric acid and incubated further, were essentially without effect on survival of S. typhimurium during refrigerated storage. Use of Streptococcus thermophilus (1% culture, 42 C incubation) yielded cultured skimmilks that were most detrimental to survival of salmonellae, whereas skimmilks fermented with Lactobacillus bulgaricus permitted survival of low numbers of salmonellae beyond 9 days. Milks cultured at 42 C with a 5% inoculum of S. thermophilus mixed with L. bulgaricus or Lactobacillus helveticus were free of viable salmonellae before the incubation was complete. Salmonellae grown in skimmilk at 21 C without a lactic culture were more resistant to inactivation during refrigerated storage than was S. typhimurium grown at 30 or 42 C.

Effect of cadmium on the growth of Lactobacillus lactis, L. helveticus and Streptococcus thermophilus in milk

1984 ◽  
Vol 51 (4) ◽  
pp. 591-596 ◽  
Author(s):  
Hannu Korkeala ◽  
Stefan Soback ◽  
Jorma Hirn
Keyword(s):  
Lactic Acid ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Skim Milk ◽  
Streptococcus Thermophilus ◽  
Inhibitory Effect ◽  
Inhibition Of Growth ◽  
Lactobacillus Lactis ◽  
Stimulation Of ◽  
Slight Inhibition

SummaryThe viable counts, pH and production of lactic acid were determined for Lactobacillus lactis, L. helveticus and Streptococcus thermophilus after 0, 5 and 24 h anaerobic incubation at 44 °C in skim milk containing 0, 3, 5 or 7μg cadmium (Cd)/l. In skim milk containing 7μg Cd/l, a noticeable decrease in lactic acid production and inhibition of the decrease in pH was observed for all three strains after 24 h, although there was only a slight inhibition of growth. With 3 and 5μg Cd/l, there was only a slight inhibition in the decrease in pH. In addition, with 3 μg Cd/l some evidence of stimulation of lactic acid production was found. The inhibitory effect of low Cd concentrations on lactic acid bacteria may give rise to problems in the dairy industry.

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