scholarly journals Enzymatic Time-Temperature Indicator Prototype Developed by Immobilizing Laccase on Electrospun Fibers to Predict Lactic Acid Bacterial Growth in Milk during Storage

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1160
Author(s):  
Ting-Yu Tsai ◽  
Shih-Hsin Chen ◽  
Li-Chen Chen ◽  
Shih-Bin Lin ◽  
Shyi-Neng Lou ◽  
...  
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Polyvinyl Alcohol ◽  
Prediction Error ◽  
Temperature Response ◽  
Electrospun Fibers ◽  
Visual Monitoring ◽  
Temperature Changes ◽  
Colony Forming Units

Laccase was immobilized on a chitosan/polyvinyl alcohol/tetraethylorthosilicate electrospun film (ceCPTL) and colored with guaiacol to obtain a laccase time–temperature indicator (TTI) prototype. The activation energy (Ea) of coloration of the prototype was 50.89–33.62 kJ/mol when 8–25 μg/cm2 laccase was immobilized on ceCPTL, and that of lactic acid bacteria (LAB) growth in milk was 73.32 kJ/mol. The Ea of coloration of the TTI prototype onto which 8–10 μg/cm2 laccase was immobilized was in the required range for predicting LAB growth in milk. The coloration endpoint of the TTI prototype onto which 10 μg/cm2 (0.01 U) laccase was immobilized could respond to the LAB count reaching 106 colony-forming units (CFU)/mL in milk during a static temperature response test, and the prediction error was discovered to be low. In dynamic temperature response experiments with intermittent temperature changes between 4 and 25 °C, the coloration rate of the laccase TTI prototype was consistent with LAB growth. The results of this study indicate that the laccase TTI prototype can be applied as a visual monitoring indicator to assist in evaluating milk quality in cold chains.

Effects of enzymes and nutrients in a bacterial inoculant on quality of timothy or alfalfa silage and dairy cow performance

1991 ◽  
Vol 71 (3) ◽  
pp. 781-791 ◽  
Author(s):  
A. H. Fredeen ◽  
R. E. McQueen ◽  
D. A. Browning
Keyword(s):  
Lactic Acid ◽  
Dairy Cow ◽  
Latin Square ◽  
Ammonia Nitrogen ◽  
Temperature Changes ◽  
Colony Forming Units ◽  
Silage Quality ◽  
Cow Performance ◽  
Silage Inoculants

Timothy (trial 1) and alfalfa (trial 2) were inoculated at ensiling (33–37% dry matter (DM)) in concrete-stave, vertical silos with a culture of lactic acid bacteria (Lab; Lactobacillus plantarum and Pediococcus acidilactici) alone, or with additional nutrients and enzymes (Supersile®, Biotal Canada, Calgary, AB), and compared with an untreated (control) silage. Colony forming units of Lab, ammonia nitrogen (NH3-N), lactic acid and volatile fatty acid concentrations, pH, DM disappearance and temperature changes during ensiling were measured to assess silage quality. Nine dairy cows in mid-lactation (alfalfa) and nine cows in late lactation (timothy) were used to evaluate inoculants in repeated Latin square designs. Timothy silage that had been inoculated with Supersile or Lab had lower concentrations of acetic and butyric acid (P < 0.05) compared with the control. No other effects on silage quality were observed, and cow performance was not affected by using inoculants on either timothy or alfalfa in this study. Enzymes added in this experiment were not beneficial. Key words: Silage, inoculants, alfalfa, timothy, dairy, cow

scholarly journals Quantification of Lactobacillussp in fermented milks marketed in Fortaleza-CE

2018 ◽  
Vol 39 (4) ◽  
pp. 302-307
Author(s):  
Ana Paula Colares de Andrade ◽  
Libanea Maria Batista Cavalcante
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Total Count ◽  
Anaerobic Conditions ◽  
Plate Technique ◽  
Brazilian Legislation ◽  
Colony Forming Units ◽  
Peptone Water ◽  
Genus Lactobacillus

This research aimed to evaluate the quantification of Lactobacillussp in three brands of fermented milks collected in the supermarkets of Fortaleza-CE. At the time of purchase of the products, it was observed that none of the lots were at an ideal coolingtemperature (up to 5 °C)according to Brazilian legislation (2002). All the evaluated products declared to have bacteria of the genus Lactobacillus, so the viability/ quantification of the probiotic cultures was monitored as a function of the total count of lactic acid bacteria in MRS agar at 37 °C under anaerobic conditions for 72h (IDF, 1995). The samples were previously diluted in peptone water (0.1%) and plated using the Spread Plate technique (ICMSF, 1978), and theresults were expressed in Colony Forming Units per mL of product (UFC/mL). It is observed that of the three brands evaluated, only one showed a significant amount of cells for the product to be considered probiotic.

scholarly journals Effect of 3-Phenyllactic Acid and 3-Phenyllactic Acid-Producing Lactic Acid Bacteria on the Characteristics of Alfalfa Silage

Agriculture ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 10 ◽  
Author(s):  
Zhe Wu ◽  
Shengyang Xu ◽  
Ying Yun ◽  
Tingting Jia ◽  
Zhu Yu
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gene Sequencing ◽  
16S Rdna Gene ◽  
Phenyllactic Acid ◽  
Colony Forming Units ◽  
Fermentation Quality ◽  
Alfalfa Silage ◽  
16S Rdna Gene Sequencing

In this study, an experiment was performed to evaluate the effect of lactic acid bacteria and 3-phenyllactic acid (PLA) on the fermentation quality and chemical composition of alfalfa silage. Several PLA-tolerant strains were screened from silages and identified. The selected strains (1 × 106 colony forming units/g fresh alfalfa) and PLA (1.0, 2.0, or 3.0 g/kg) were applied to alfalfa before ensiling. After 45 days of storage, the silages were unsealed and subjected to component analysis. Biochemical methods and 16S rDNA gene sequencing were used for the identification of the two strains as Lactobacillus plantarum. The characteristics of chemical and fermentation compounds indicated that PLA and the two strains efficiently improved the quality of the alfalfa silage. It can be concluded that the use of the strains and PLA can significantly improve the quality of silage.

Biogenic Amine Formation in Fresh Vacuum-Packaged Beef Stored at −2°C and 2°C for 100 Days

1995 ◽  
Vol 58 (3) ◽  
pp. 284-288 ◽  
Author(s):  
ANGELIA R. KRIZEK ◽  
J. SCOTT SMITH ◽  
RANDALL K. PHEBUS
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Biogenic Amine ◽  
Storage Temperature ◽  
Tap Water ◽  
Meat Products ◽  
Treatment Groups ◽  
Colony Forming Units ◽  
Plate Counts ◽  
Packaged Beef

When fresh, vacuum-packaged, meat products are stored for extended periods of time, undesirable changes, due to naturally occurring microbial flora present during packaging occur. Lactobacillus spp. are known to form amines through the decarboxylation of free amino acids. Tyramine and histamine can cause intoxication in individuals taking monoamine oxidase-inhibiting drugs. This study determined 1) the effect of storage temperature on bacterial growth and biogenic amine production in vacuum-packaged beef subprimals, 2) the effect of washing subprimals with water to remove tyramine contamination, and 3) the penetration of tyramine from the surface of the subprimal. Inside rounds were vacuum packaged and stored at −2°C or 2°C. Samples were evaluated over 100 days for amine concentrations, total psychrotrophic counts and lactic acid bacteria. Tyramine, putrescine and cadaverine were detected in this study. Significant levels (15 μg/g) of tyramine were detected at 20 days of storage at 2°C and 40 days of storage at −2°C. Putrescine and cadaverine were detected first at 40 days of storage at 2°C and 60 days of storage at −2°C. Both treatment groups contained about 130 μg/g of tyramine at 100 days of storage. Psychrotrophic plate counts and lactic acid bacteria counts were initially 103 colony forming units (CFU)/cm2 and ranged from 106–107 CFU/cm2 at 100 days of storage. Even though tyramine was evident at a depth of 6 mm from the surface of the cut, one-third of the amine was removed by washing the subprimal with tap water.

scholarly journals Novel Polyvinyl Alcohol/Starch Electrospun Fibers as a Strategy to Disperse Cellulose Nanocrystals into Poly(lactic acid)

Polymers ◽  
2017 ◽  
Vol 9 (12) ◽  
pp. 117 ◽  
Author(s):  
Carol López de Dicastillo ◽  
Karina Roa ◽  
Luan Garrido ◽  
Alejandro Pereira ◽  
Maria Galotto
Keyword(s):  
Lactic Acid ◽  
Polyvinyl Alcohol ◽  
Cellulose Nanocrystals ◽  
Poly Lactic Acid ◽  
Electrospun Fibers

scholarly journals Lactic acid fermentation of fish offal and chicken by-product with different starter cultures

1995 ◽  
Vol 4 (1) ◽  
pp. 19-26
Author(s):  
T. Mikael Lassén
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Redox Potential ◽  
Lactic Acid Fermentation ◽  
Starter Cultures ◽  
Clupea Harengus ◽  
Acid Fermentation ◽  
Stable Level ◽  
Colony Forming Units ◽  
By Products

Lactic acid fermentation was evaluated as a method to preserve fish and chicken by-products. Herring (Clupea harengus) by-products (viscera and heads) and chicken by-products (heads, viscera, feathers, feet and discarded whole chickens) were minced, mixed with 5% dextrose and inoculated with 108 colony forming units (cfu)/g of four different lactic acid bacteria cultures. The by-product was fermented at 25°C and evaluated for pH, % produced lactic acid, redox potential and odour during four weeks' storage. In herring offal, pH decreased from 6.8 to 4.2 in one week and stabilized at about 4.3. In the same time, 2.0% to 3.2% lactic acid was produced and concentrations stabilized from 2.5% to 4.0%. In chicken offal, pH decreased to a stable level of 4.4, and 3.2% lactic acid was produced after one week of fermentation. A negative and stable redox potential was achieved after one week of fermentation in both herring and chicken offal.

Optimization of an effective growth medium for culturing probiotic bacteria for applications in strict vegetarian food products

2012 ◽  
Vol 2 (10) ◽  
pp. 369 ◽  
Author(s):  
Manju Pathak ◽  
Danik Martirosyan
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Growth Medium ◽  
Culture Medium ◽  
Culture Media ◽  
Plant Seed ◽  
Meat Extract ◽  
Colony Forming Units ◽  
Lactobacillus Lactis ◽  
De Man

Background: This study aimed to modify de Man Rogosa Sharpe culture medium (termed MRS) for selective cultivation of probiotics strain for the consumption by the strictly vegetarian human population. Vegetarian probiotic foods by definition must be free from all animal-derived ingredients. This not only includes the product ingredients but the probiotic inoculum as well. Probiotic starter cultures are traditionally grown and stored in media containing milk or meat-derived ingredients. The presence of these ingredients makes the probiotic cell concentrates unsuitable for use in vegetarian products and thus creates the need for a growth medium which is free from animal-derived ingredients. Present study investigated the growth of a strain of Lactobacillus lactis in MRS. The present invention relates in general to a bacterial culture media, and more specifically a complex microbial culture media, based on plant seed powder extract in place of animal extract for probiotic bacterial growth.Methods: Lactobacillus lactis, a probiotic, was grown in standard MRS culture medium as well as in our various test media (TM) containing various vegetal source in place of beef extract, yeast extract and peptone as in case of MRS. The inoculated culture mediums were incubated at 37C for 72 hours and growth of probiotic is recorded at regular intervals. The growth was recorded as Colony Forming Units (CFUs).Results: The best growth of probiotic is observed in TM 2. TM 2 is the leguminous seed extract. Starter culture mediums for probiotics or other bacteria primarily contain protein from animal source. The possibility of using vegetal protein from TM 2 extract in place of peptones and meat extract for the nitrogen supplementation of culture media for the growth of lactic acid bacteria has been demonstrated. Conclusion: The absolute vegetarian culture medium containing TM 2 is better than standard MRS for the growth of probiotics.Abbreviations: de Man Rogosa Sharpe (MRS), Colony Forming Units (CFU), test media (TM), National Dairy Research Institute (NDRI), Tamarind seed powder (TSP), solid-state fermentation (SSF), Lactobacillus casei Shirota (LcS)Keywords: probiotics, lactic acid bacteria, vegetarian

Biogenic Amine Changes Related to Lactic Acid Bacteria During Brewing

1996 ◽  
Vol 59 (2) ◽  
pp. 175-180 ◽  
Author(s):  
MARIA IZQUIERDO-PULIDO ◽  
JUDIT FONT-FÀBREGAS ◽  
JOSEP-MIQUEL CARCELLER-ROSA ◽  
ABEL MARINÉ-FONT ◽  
CARMEN VIDAL-CAROU
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Biogenic Amine ◽  
Microbial Contamination ◽  
Great Variability ◽  
Wild Yeast ◽  
As Species ◽  
Acid Washing ◽  
Colony Forming Units ◽  
Wild Yeasts

Biogenic amine contents and microbial contamination (wild yeasts and lactic acid bacteria) were followed during beer fermentation in both industrial and pilot plants. No significant change in the amine contents was observed, except for tryptamine and tyramine. Tyramine formation showed a great variability (from 8 to almost 30 mg/l), while tryptamine formation was always much lower than tyramine (&lt;3.5 mg/l). No relationship was found between wild yeast counts and tyramine formation, whereas a significant positive relationship was found between tyramine formation and lactic acid bacteria. Colony-forming units (CFU) of these microorganisms ranging from 4 × 103 to 1 × 104 CFU/ml were related to low tyramine production (&lt;5 mg/l). Tyramine formation between 5 and 15 mg/l was related to lactic acid bacteria counts from 1 × 104 to 1 × 105 CFU/ml, while lactic acid bacteria higher than 1 × 105 CFU/ml were related to tyramine formation between 15 and 25 mg/l. No marked tyramine production occurred when lactic acid bacteria counts were lower than 4 × 103 CFU/ml. The lactic acid bacteria isolated were identified as species of Pediococcus. Secondary fermentation was not related to tyramine formation. Phosphoric acid washing of the brewer's yeast was effective in eliminating Pediococcus spp. and, therefore, in reducing tyramine levels in the final product.

scholarly journals Orally administeredLactobacillus plantarumreduces pro-inflammatory interleukin secretion in sera fromListeria monocytogenesinfected mice

2007 ◽  
Vol 99 (4) ◽  
pp. 819-825 ◽  
Author(s):  
Elena Puertollano ◽  
María A. Puertollano ◽  
Lidia Cruz-Chamorro ◽  
Gerardo Álvarez de Cienfuegos ◽  
Alfonso Ruiz-Bravo ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Host Resistance ◽  
Human Subjects ◽  
Lethal Dose ◽  
Host Protection ◽  
Colony Forming Units ◽  
Tnf Α

Lactic acid bacteria have traditionally been thought to have immunomodulating effects. To verify this property,Lactobacillus plantarumwas orally administered to mice (5 × 107colony forming units (c.f.u.)), prior to infection withListeria monocytogenesin order to evaluate the host resistance against an infectious micro-organism and to better define the influence ofL. plantarumon such responses. Balb/c mice were treated daily withL. plantarumor received PBS (sham-treated mice as controls) for 4 weeks. Subsequently, mice were intravenously infected with a clinical isolate ofL. monocytogenes. Our study revealed that the administration ofL. plantarumdid not significantly increase the survival (P = 0·13) of mice (fifteen in each group) afterL. monocytogenesinfection (106 c.f.u./ml), whereas a sub-lethal dose ofL. monocytogenes(105 c.f.u./ml) was eliminated from liver and spleen 5 d after the challenge in bothL. plantarum- and sham-treated mice (n5). Nevertheless, the levels of IL-1β and IL-6 from sera of orally administeredL. plantarumwere drastically reduced at 0, 4 (P < 0·01) and 6 d afterL. monocytogenesinfection, whereas TNF-α production was unaltered. In conclusion, administration ofL. plantarumreduced pro-inflammatory IL production after challenge withL. monocytogenes, although it did not significantly impact the survival of mice. We speculate thatL. plantarumcould exert anti-inflammatory effects, which may represent an important model to reduce inflammatory disorders. Therefore, further studies in human subjects should determine the role ofL. plantarumas an immunomodulatory micro-organism and its relationship in the host protection to pathogens.

Changes in carbohydrate and protein fractions during ensiling of alfalfa treated with previously fermented alfalfa juice or lactic acid bacteria inoculants

2018 ◽  
Vol 58 (3) ◽  
pp. 577
Author(s):  
L. Tao ◽  
H. Zhou ◽  
N.-F. Zhang ◽  
B.-W. Si ◽  
Y. Tu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Fatty Acid ◽  
Lactic Acid Bacteria ◽  
Protein Degradation ◽  
Volatile Fatty Acid ◽  
Fatty Acid Content ◽  
Fresh Weight ◽  
Protein Nitrogen ◽  
Soluble Fibre ◽  
Colony Forming Units

The effects of previously fermented juice (PFJ) prepared from alfalfa and lactic acid bacteria (LAB) inoculants on the dynamic changes of nutritive components in ensiled alfalfa after various ensiling periods were investigated by using the Cornell Net Carbohydrate and Protein System. The third-cut alfalfa was harvested at the budding stage, exposed to sunlight, weighed occasionally to estimate the dry matter (DM) content until the actual DM finally obtained was 347.8 g/kg fresh weight, and then chopped to 1–2-cm lengths. Chopped forages were treated with (1) distilled water (control), (2) alfalfa PFJ or (3) LAB at 1 mL/50 g fresh weight. The application amounts of PFJ and LAB to the fresh forage were 8.73 log (colony-forming units/mL) and 7.32 log (colony-forming units/mL) respectively. All silages were prepared in mini-silos of 100-mL polypropylene centrifuge tubes and kept in an incubator at 30°C, and triplicate silos from each treatment were opened after 1, 3, 7, 14 and 35 days of ensiling. Results suggested that silage treated with LAB and PFJ was of better quality than was the control silage, as evidenced by lower volatile fatty acid concentrations, as well as higher lactic acid, sugar, starch, soluble fibre and digestible natural detergent fibre production at various ensiling periods (P < 0.05), and a lower protein degradation as suggested by the low non-protein nitrogen production (P < 0.05). The effect of PFJ on alfalfa fermentation quality and protein degradation was greater than that of LAB, as evidenced by the lower pH value and volatile fatty acid content and the higher concentrations of lactic acid (P < 0.05). In addition, the cost of PFJ for 1 tonne of alfalfa silage is ~1/7–1/5 of that of LAB. In conclusion, adding PFJ to alfalfa forages before preservation as silage is a cost-effective way to improve the silage formation quality; in addition, its effect as a fermentation stimulant may be comparable to, or even better than, that of LAB inoculants at various ensiling periods.

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