Survival and residual activity ofLactobacillus acidophilusfrozen cultures under different conditions

1996 ◽  
Vol 63 (2) ◽  
pp. 295-303 ◽  
Author(s):  
Roberto Foschino ◽  
Enrico Fiori ◽  
Antonietta Galli
Keyword(s):  
Lactobacillus Acidophilus ◽  
Total Population ◽  
Storage Temperature ◽  
Lactic Acid Production ◽  
Survival Rates ◽  
Residual Activity ◽  
Skim Milk ◽  
Selective Media ◽  
Active Population ◽  
Fermentative Activity

SummaryEight strains of theLactobacillus acidophiluscomplex were subjected, as concentrated cultures in skim milk, to different freezing treatments (rapidly in liquid nitrogen and more slowly in cold air at −30 °C), then stored at −80 and −30°C for 9 months. Survival was determined by plate counting with and without bile salts or sodium chloride at the highest tolerated concentration for each strain, to distinguish the undamaged population from the total population. Fermentative activity was measured as total lactic acid production by thawed cultures under standard conditions. Higher survival rates and greater activity were always obtained by storing cultures at −80 °C, but most strains stored at −30°C also survived well. Analysis of variance revealed that the viability of the frozen cultures was affected more by storage temperature than by cooling rate. Selective media were unable to distinguish the active population from the total surviving population. The correlation between values for activity and survival with selective media was poor.

scholarly journals Survivability of Lactobacillus acidophilus and quality attributes of puffed pounded-unripe rice supplemented with probiotics using a fluidized-bed coating method

Food Research ◽  
2021 ◽  
Vol 4 (S4) ◽  
pp. 73-80
Author(s):  
W. Duangkhamchan ◽  
P. Itsaranuwat
Keyword(s):  
Cell Count ◽  
Fluidized Bed ◽  
Lactobacillus Acidophilus ◽  
Survival Rates ◽  
Skim Milk ◽  
Value Added ◽  
Textural Properties ◽  
Thiobarbituric Acid ◽  
Fluidized Bed Coating ◽  
Coating Method

Value-added breakfast cereals are receiving increased interest due to changes in lifestyles and modern trends of health awareness among consumers. Among various cereal grains, puffed pounded-unripe rice (PPUR) was chosen because of its excellent health beneficial properties. Feasibility of supplementing the probiotic bacteria Lactobacillus acidophilus (LA5) into PPUR was investigated using a fluidized-bed coating method. Suitable fermentation conditions were tested based on a pH criterion of 4.5. Three types of cell host solutions as sucrose, skim milk and maltodextrin were examined as suitable carriers, and optimal coating condition was determined. Product qualities were evaluated for stability. Results showed that milk fermented for 24 hrs gave the highest viable cell count of approximately 109 to 1010 CFU/mL when optimally mixed with distilled water at milk: water ratio of 45:105. Skim milk was determined as the most suitable host giving the highest retention of LA5 cell count. Coating condition at a feed rate of 10 mL/min, coating time of 5 mins and constant temperature at 50°C gave the highest survival rates of LA5. Moisture contents and water activity (aw) values of all coated products ranged from 3.38-3.72% wb and 0.201-0.232, respectively. Regarding textural properties, coated PPUR showed increased hardness and crispiness compared with uncoated samples, while the variation of coating conditions had no significant effects. Dynamic changes in viable LA5 cell count, textural properties, aw, peroxide value and thiobarbituric acid values fitted well with various kinetic orders. Findings indicated the feasibility of adding probiotics to dry products associated with suitable coating solution and offered guidance for product development and process design.

scholarly journals Changes in Particle Size, Sedimentation, and Protein Microstructure of Ultra-High-Temperature Skim Milk Considering Plasmin Concentration and Storage Temperature

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2339
Author(s):  
So-Yul Yun ◽  
Jee-Young Imm
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Storage Temperature ◽  
Whey Proteins ◽  
Skim Milk ◽  
Storage Period ◽  
Sediment Analysis ◽  
Sediment Formation ◽  
And Storage ◽  
Ultra High Temperature

Age gelation is a major quality defect in ultra-high-temperature (UHT) pasteurized milk during extended storage. Changes in plasmin (PL)-induced sedimentation were investigated during storage (23 °C and 37 °C, four weeks) of UHT skim milk treated with PL (2.5, 10, and 15 U/L). The increase in particle size and broadening of the particle size distribution of samples during storage were dependent on the PL concentration, storage period, and storage temperature. Sediment analysis indicated that elevated storage temperature accelerated protein sedimentation. The initial PL concentration was positively correlated with the amount of protein sediment in samples stored at 23 °C for four weeks (r = 0.615; p < 0.01), whereas this correlation was negative in samples stored at 37 °C for the same time (r = −0.358; p < 0.01) due to extensive proteolysis. SDS-PAGE revealed that whey proteins remained soluble over storage at 23 °C for four weeks, but they mostly disappeared from the soluble phase of PL-added samples after two weeks’ storage at 37 °C. Transmission electron micrographs of PL-containing UHT skim milk during storage at different temperatures supported the trend of sediment analysis well. Based on the Fourier transform infrared spectra of UHT skim milk stored at 23 °C for three weeks, PL-induced particle size enlargement was due to protein aggregation and the formation of intermolecular β-sheet structures, which contributed to casein destabilization, leading to sediment formation.

scholarly journals Antibacterial effect of the adhering human Lactobacillus acidophilus strain LB.

1997 ◽  
Vol 41 (5) ◽  
pp. 1046-1052 ◽  
Author(s):  
M H Coconnier ◽  
V Liévin ◽  
M F Bernet-Camard ◽  
S Hudault ◽  
A L Servin
Keyword(s):  
Lactobacillus Acidophilus ◽  
Culture Supernatant ◽  
Oral Treatment ◽  
Shigella Flexneri ◽  
Lactic Acid Production ◽  
Heat Stable ◽  
Wide Range ◽  
Production Activity ◽  
Acidic Conditions

The spent culture supernatant of the human Lactobacillus acidophilus strain LB produces an antibacterial activity against a wide range of gram-negative and gram-positive pathogens. It decreased the in vitro viability of Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium, Shigella flexneri, Escherichia coli, Klebsiella pneumoniae, Bacillus cereus, Pseudomonas aeruginosa, and Enterobacter spp. In contrast, it did not inhibit lactobacilli and bifidobacteria. The activity was heat stable and relatively sensitive to enzymatic treatments and developed under acidic conditions. The antimicrobial activity was independent of lactic acid production. Activity against S. typhimurium SL1344 infecting human cultured intestinal Caco-2 cells was observed as it was in the conventional C3H/He/oujco mouse model with S. typhimurium C5 infection and oral treatment with the LB spent culture supernatant.

Study on Labour Force in Romanian Agriculture

2018 ◽  
Vol 7 (2) ◽  
pp. 36-44 ◽  
Author(s):  
Maria Nica
Keyword(s):  
Unemployment Rate ◽  
Agricultural Production ◽  
Total Population ◽  
Labour Force ◽  
Labour Productivity ◽  
Current Level ◽  
Active Population ◽  
Current Context ◽  
The Unemployed ◽  
Total Labour

This article describes how in the current context, there are many opinions in Romania which lead to the claim that there is no longer a labour force in agriculture, especially the seasonal labour force. In the present article, it is desirable to analyse the dynamics of the agricultural labour force in recent years as well as to determine the current level, but also its productivity. Thus, with the data collected from the national, European and international databases on the total population, indicators such as the active population, the employed population, the share in the total labour force, as well as the unemployed and the unemployment rate were analysed. In order to determine labour productivity, total agricultural production is analysed along with the indicators presented above. At the end of the study, the author also analyses the earnings of the population working in agriculture, trying to determine how this indicator influences the workforce in this sector of the national economy.

Effect of different encapsulating agent combinations on viability of Lactobacillus casei Shirota during storage, in simulated gastrointestinal conditions and dairy dessert

2019 ◽  
Vol 25 (7) ◽  
pp. 608-617 ◽  
Author(s):  
Osman Gul ◽  
Ilyas Atalar ◽  
Latife Betul Gul
Keyword(s):  
Lactobacillus Casei ◽  
Freeze Drying ◽  
Survival Rates ◽  
Skim Milk ◽  
Gum Arabic ◽  
Storage Conditions ◽  
Ternary Mixtures ◽  
Gastrointestinal Conditions ◽  
Lactobacillus Casei Shirota ◽  
Free Cells

In this study, the effects of various matrices consisting of maltodextrin and reconstitute skim milk and their binary and ternary mixtures with gum Arabic in the microencapsulation of Lactobacillus casei Shirota by freeze-drying technique were assessed. Microcapsules produced with reconstitute skim milk showed high viability (>99%) after freeze drying. While the free cells were completely inactivated after exposure to simulated gastrointestinal conditions, the survival rates of microencapsulated L. casei Shirota were found high for all microcapsules except for maltodextrin and maltodextrin:gum Arabic formulas. The viability of microencapsulated L. casei Shirota during storage at refrigerate and room temperatures decreased between 0.39 and 2.43 log cycles and microcapsules produced with reconstitute skim milk:gum Arabic was found more durable at the both storage conditions. Reduction in the number of free cells was higher than encapsulated L. casei Shirota numbers during production of dessert, however the viability of encapsulated L. casei Shirota was found stable for 14 days of storage and consequently desserts containing encapsulated L. casei Shirota (except maltodextrin) showed stable pH values. This study revealed that combination of reconstitute skim milk:gum Arabic was an effective wall matrix for microencapsulation of L. casei Shirota by freeze drying and also very resistant against gastrointestinal fluids and storage conditions in view of protection of L. casei Shirota.

INHIBITION OF GROWTH OF AIRBORNE COLIFORMS AND OTHER BACTERIA ON SELECTIVE MEDIA1

1972 ◽  
Vol 35 (3) ◽  
pp. 156-162 ◽  
Author(s):  
Attila K. Stersky ◽  
T. I. Hedrick
Keyword(s):  
Methylene Blue ◽  
Skim Milk ◽  
Enterobacter Aerogenes ◽  
Colony Growth ◽  
Coliform Bacteria ◽  
Plate Count ◽  
Pseudomonas Fragi ◽  
Selective Media ◽  
Standard Plate Count ◽  
Plate Count Agar

Coliforms when sampled from air were inhibited or restricted in growth on regular selective media. For trials, growth on Standard Plate Count Agar ( SPC) was used as 100%. The percentage of colony growth of Escherchia coli and Enterobacter aerogenes on modified selective media or with SPC were respectively as follows: violet red bile/violet red bile (VRB/VRB) (overlay on base) &lt;4, 15; desoxycholate/desoxyeholate (DES/DES) &lt; 1, 17; tergitol/tergitol (TER/TER) 23,49; eosine methylene blue/eosine methylene blue (EMB/EMB) 122, 86; endo/endo (END/END) 40, 104; MacConkey/MacConkey (MAC/MAC) &lt;2, 10; SPC/VRB &lt;2, 22; SPC/DES &lt;2, 23; VRB/SPC 54, 60; TER/SPC 72, 119; EMB/SPC 97, 119; END/SPC 95, 90; 1 VRB: 1 SPC, as overlay and base 14, 50. Recovery percentages of Pseudomonas aeruginosa and Pseudomonas fragi on modified selective media were greater than those of the coliform bacteria. Fewer Serratia marcescens colonies grew on DES or SPC/DES and more grew on the other modified selective media than did coliform colonies. Growth of airborne Salmonella newbrumwick ranged from &lt;1% on SS agar to 118% on MAC/SPC. Aerosolization of coliforms with skim milk compared to distilled water resulted in growth of more colonies on selective media. Desoxycholate, Bile Salts No. 3, Tergitol No. 7, and crystal violet in the media definitely limited growth of airborne coliforms.

Spray Method for Recovery of Heat-Injured Salmonella Typhimurium and Listeria monocytogenes

2012 ◽  
Vol 75 (10) ◽  
pp. 1867-1872 ◽  
Author(s):  
KYEONG-HWAN BACK ◽  
SANG-OH KIM ◽  
KI-HWAN PARK ◽  
MYUNG-SUB CHUNG ◽  
DONG-HYUN KANG
Keyword(s):  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Recovery Rate ◽  
Skim Milk ◽  
Selective Media ◽  
Spray Method ◽  
Selective Agar ◽  
Overlay Method ◽  
Peptone Water ◽  
Pathogen Recovery

Selective agar is inadequate for supporting recovery of injured cells. During risk assessment of certain foods, both injured and noninjured cells must be enumerated. In this study, a new method (agar spray method) for recovering sublethally heat-injured microorganisms was developed and used for recovery of heat-injured Salmonella Typhimurium and Listeria monocytogenes. Molten selective agar was applied as an overlay to presolidified nonselective tryptic soy agar (TSA) by spray application. Heat-injured cells (55°C for 10 min in 0.1% peptone water or 55°C for 15 min in sterilized skim milk) were inoculated directly onto solidified TSA. After a 2-h incubation period for cell repair, selective agar was applied to the TSA surface with a sprayer, and the plates were incubated. The recovery rate for heat-injured Salmonella Typhimurium and L. monocytogenes with the spray method was compared with the corresponding rates associated with TSA alone, selective media alone, and the conventional overlay method (selective agar poured on top of resuscitated cells grown on TSA and incubated for 2 h). No significant differences (P &gt; 0.05) were found in pathogen recovery obtained with TSA, the overlay method, and the spray method. However, a lower recovery rate (P &lt; 0.05) was obtained for isolation of injured cells on selective media. Overall, these results indicate that the agar spray method is an acceptable alternative to the conventional overlay method and is a simpler and more convenient approach to recovery and detection of injured cells.

scholarly journals Produksi Asam Laktat dari Fermentasi Limbah Cair Olahan Kelapa dengan Variasi Konsentrasi Inokulum Lactobacillus acidophilus

2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Ratna Ratna ◽  
Ulfa Triovanta ◽  
Darwin Darwin
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Acidophilus ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Liquid Waste ◽  
Total Suspended Solid ◽  
Strong Relationship ◽  
Suspended Solid ◽  
Continuous Systems ◽  
Inoculum Concentration

The aim of this research is to study the fermentation technique of coconut processed liquid waste by varying the inoculum concentration of Lactobacillus acidophilus bacteria for lactic acid production. This research was carried out in several steps, namely the first step was the inoculum cultivation process of Lactobacillus acidophilus bacteria, the second step was the fermentation process of coconut water with variations in the concentration of Lactobacillus acidophilus bacteria inoculum, namely 5%, 10% and 20%. Analysis of lactic acid products, pH, glucose, Total Dissolved Solid (TDS), Total Suspended Solid (TSS) and Volatile Suspended Solid (VSS). The variation in the concentration of Lactobacillus acidophilus bacteria inoculum 20% is the most optimum to produce total lactic acid for batch and continuous systems. The results of the correlation analysis for inoculum variations of 5%, 10% and 20% had a strong relationship with lactic acid production, decreased pH and decreased glucose levels. The greater the inoculum concentration, the greater the decrease in the TDS, TSS and VSS content.

scholarly journals Correlation of Some Substrate Parameters in Growing Lactobacillus acidophilus on Vegetable and Fruit Cocktail Juices

2010 ◽  
Vol 67 (2) ◽  
Author(s):  
Carmen Leane NICOLESCU ◽  
Lavinia Claudia BURULEANU
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Acidophilus ◽  
Acid Production ◽  
Sugar Content ◽  
Lactic Acid Production ◽  
Biomass Accumulation ◽  
Reducing Sugar ◽  
Fruit Juices ◽  
Cell Multiplication ◽  
Microbiological Methods

Using Lactobacillus acidophilus stains is a challenge in producing lactic acid fermented vegetable and fruit juices. There were analysed the correlation between the most important physico-chemical parameters of the substrate and the bacterial biomass accumulation in two vegetable and fruit juices. The data were collected during a 48 hour lactic acid fermentation using usually chemical and microbiological methods. There was analysed the correlation between the reducing sugar content and the lactic acid production, the correlation between the pH and lactic acid production, the correlation between the reducing sugar of the substrate and the microbial biomass accumulation and also between the lactic acid production and biomass accumulation. These correlations were analysed using simple regression on scatter plots. They were best fitted by the polynomial equation where the highest R2 were calculated. The two last correlations had large differences between the two experimental batches so that regression is not satisfactory to describe them. If all parameters were considered using the multiple regression, the correlation had a medium value because the cell multiplication of the bacteria Lactobacillus acidophilus in vegetable and fruit juices is influenced by many other environmental parameters. These had a large influence because juices are not the natural medium for this kind of lactic acid bacteria.

scholarly journals VIABILITY OF LACTOBACILLUS acidophilus AND SYNERESIS OF PROBIOTIC YOGHURT PRODUCED FROM RECONSTITUTED SKIM AND WHOLE MILK POWDER DURING 35 DAYS REFRIGERATED STORAGE AT 4±2 oC

2019 ◽  
Vol 2 (2) ◽  
pp. 54
Author(s):  
Obhioze Augustine Akpoka ◽  
T. E Obi
Keyword(s):  
Lactobacillus Acidophilus ◽  
Starter Culture ◽  
Milk Powder ◽  
Skim Milk ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Probiotic Bacteria ◽  
Whole Milk ◽  
Freeze Dried ◽  
Whole Milk Powder

Currently, the food industry wants to expand the range of probiotic yogurts but each probiotic bacteria offers different and specific health benefits. This study examined the viable counts of Lactobacillus acidophilus and percentage syneresis of probiotic yoghurt produced from reconstituted skim and whole milk powder stored for 35 days at 4±2 oC. Skim milk probiotic yoghurt (SMPY) and Whole milk probiotic yoghurt (WMPY) were produced by reconstituting dry milk powder (130 g/900 ml w/v), which was pasteurized at 85 oC for 15 mins, cooled to 43 oC and inoculated with freeze dried probiotic yoghurt mixed starter culture containing Streptococcus thermophilus (ST), Lactobacillus bulgaricus (LB) and Lactobacillus acidophilus (LA). The yoghurt samples were analyzed for viability of ST, LB, LA and also syneresis. During storage, the viable counts of ST in SMPY decreased from 5.43x108 to 5.18x106 cfu/ml, LB (2.47x108 to 8.10x105 cfu/ml) and LA (1.83x108 to 5.78x105 cfu/ml). Similarly, the viable counts of ST in WMPY decreased significantly from 5.40x108 to 5.15x106 cfu/ml, LB (2.43x108 to 7.82x105 cfu/ml) and LA (1.80x108 to 5.84x105 cfu/ml). Although the mean viable counts of the LA decreased during storage, both SMPY and WMPY still contained an average of 1.48x106 cfu/ml of probiotic cells up to 28 days of storage, which is above the “therapeutic minimum” of 106 cfu/ml. The percentage syneresis of SMPY and WMPY increased significantly during the 35 days of storage, from 24.4-32.0 % and 24.8-32.7 % respectively. There was a positive correlation between storage time and syneresis thus affecting the texture. In conclusion, yoghurt made from either skim or whole milk powder can be used as an adequate carrier of LA (probiotic bacteria) up to a period of 28 days at 4±2 oC and a stabilizer should be used to reduce the separation of whey and thus maintain the texture.

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