scholarly journals One- and Two-Step Kinetic Data Analysis Applied for Single and Co-Culture Growth of Staphylococcus aureus, Escherichia coli, and Lactic Acid Bacteria in Milk

2021 ◽  
Vol 11 (18) ◽  
pp. 8673
Author(s):  
Pavel Ačai ◽  
Ľubomír Valík ◽  
Alžbeta Medveďová

The objective of this study was to compare one- and two-step kinetic data analysis approaches to describe the growth of Staphylococcus aureus, Escherichia coli, and lactic acid bacteria Fresco 1010 starter culture in milk under isothermal conditions between 10 and 37 °C. The primary Huang model (HM) and secondary square root model were applied to lag times and growth rates of each of the population. The one-step approach for single cultures data enabled the direct construction of a tertiary model combining primary and secondary models to determine parameters from all growth data, thus minimizing the transfer of errors from one model to another. The statistical indices showed a significant improvement in the prediction capability provided by this approach. Then, a one-step approach combining the primary Huang, Giménez, and Dalgaard model (H-GD) with the secondary square root model was used to simultaneously model the growth of the populations mentioned above in co-culture under the same conditions. Independent isothermal data sets were chosen for validation of the growth description of single cultures (HM) and co-culture (H-GD) using validation factors, including the bias (Bf) and accuracy (Af). For example, the values of Af for the one-step approach range from 1.17 to 1.20 and 1.04 to 1.08 for single cultures and co-culture, respectively, demonstrating high accuracy. Thus, this approach may be used for co-culture growth description in general or specifically, e.g., in various types of lactic acid fermentation, including artisanal cheese-making technology.

2012 ◽  
Vol 534 ◽  
pp. 78-81
Author(s):  
Ting Wei Hu ◽  
Shao Yun Shan ◽  
Shi Mei Yang ◽  
Li Hong Jiang ◽  
Ya Ming Wang ◽  
...  

Polyaniline(PANI)/TiO2 nanocomposites are successful synthesized by one step-interfacial polymerization method. Morphologies and structures of the nanocomposites are characterized using SEM, FTIR, and XRD. The antibacterial properties of PANI/TiO2 nanocomposites on Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Bacillus megateriu and Bacillus cereus are tested. The effect of molar ratio of aniline and tetrabutyl titanate on structures and antibacterial properties are also been explored. The results show that the content of tetrabutyl titanate has a obvious influence on structure and morphologies of the nanocomposites. PANI/TiO2 nanocomposites have antibacterial properties especially on Staphylococcus aureus and Escherichia coli, which shows a best antibacterial property when the molar ratio of aniline to tetrabutyl titanate is 3:2.


2002 ◽  
Vol 73 (2-3) ◽  
pp. 145-157 ◽  
Author(s):  
Kristel Bernaerts ◽  
Roos D. Servaes ◽  
Steven Kooyman ◽  
Karina J. Versyck ◽  
Jan F. Van Impe

2013 ◽  
Vol 781-784 ◽  
pp. 1681-1684
Author(s):  
Hong Man Hou ◽  
Gong Liang Zhang ◽  
Li Ming Sun

Cholesterol-lowering effect of lactic acid bacteria is well-known. In this study, nine cholesterol-lowering Lactobacillus strains from Chinese traditional cheese, pickle and yoghurt were screened and characterized for their potential use. The microbial content of all the strains was significantly decreased at pH 1.5, but the residual counts of L. casei subsp. casei GL-03, L. plantarum ZP-Z, L. plantarum ZP-05 and L. brevis ZP-04 were more than 107cfu/mL after 6h of incubation. All the nine strains of Lactobacillus indicated good tolerance to bile at concentration less than 0.2% after 2 or 6 h of incubation. L. plantarum ZP-W had maximum hydrophobicity towards xylene while GL-03 strain possessed maximum hydrophobicity for both hexadecane and octane. ZP-05 strain had more effective inhibitory activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Shigella dysenteriae than other eight strains. These results suggest that L. casei subsp. casei GL-03 may be effective as a probiotic with cholesterol-lowing activities.


2001 ◽  
Vol 56 (1-2) ◽  
pp. 82-88 ◽  
Author(s):  
Ahmed G. Hegazi ◽  
Faten K. Abd El Hady

Abstract The antimicrobial activity of four propolis samples collected from Upper Egypt against Staphylococcus aureus; Escherichia coli and Candida albicans was evaluated. There was a variation in the antimicrobial activity according to the propolis origin. Banisweif propolis showed the highest antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans, but Fayoum propolis had moderate activity against all tested pathogens. Propolis collected from Assiut and Souhag gave lower antimicrobial activity. Propolis samples were investigated by GC/MS, 71 compounds were identified, 14 being new for propolis. Banisweif propolis is characterized by the presence of 7 caffeate esters and 4 triterpenoids. Fayoum propolis showed the highest amount of lactic acid and the presence of 3 chalcones. But Assiut propolis is characterized by the presence of 4 prenylated coumar-ates. Souhag propolis is characterized by the presence of 5 aliphatic dicarboxylic acids and some other new compounds to propolis.


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