Morphology evolution of gold nanoparticles as function of time, temperature, and Au(III)/sodium ascorbate molar ratio

Abstract: In this work the morphology evolution of Au nanoparticles (AuNPs), obtained by direct reduction, was studied as a function of time, temperature, and Au(III)/sodium ascorbate molar ratio. The NPs morphology was examined by transmission electron microscope with image analysis, while time evolution was investigated by visible and near-infrared absorption spectroscopy and dynamic light scattering. It is found that initially formed star-like NPs transform in more spheroidal particles and the evolution appears more rapid by increasing the temperature while a large amount of reducing agent prevents the remodeling of AuNPs. An explication of morphology evolution is proposed. Graphical Abstract: [Figure not available: see fulltext.

Validation of the Micro Biological Survey Method for Total Viable Count and E. coli in Food Samples

""The rom of this study was the validation of the Micro Biological Survey (MBS) method for. microbiological analysis of food for Total Viable Count (TVC) and Escherichia coli (E. coli), The. MBS method is a rapid quantitative alternative method for the detection and selective counting of. bacteria in agro-food, in water and in environmental samples. It is based on colorimetric survey in. mono-uss disposable reaction vials that must be filled with the samples without any preliminary. treatment (e.g., homogenization, dilution, etc.); the greater the number ofbacteria presents into. the sample, the faster the color change. However, an independent evaluation of the analytical. results obt.ained with MBS method would be required before commercialization. Therefore, this. alternative method was validated in comparison to the reference method. The general estimate of. precision, reliability, uncertainty, linearity, accuracy and selectivity were determined. Ali the. performance parameters have demonstrated total corrslation between the alternative method and. the reference method for the detection and counting of TVC and E. coli both in artificially. contaminated and in naturaliy contaminated samples. MBS assay can be used as rapid and user. friendly screening method for detection of TVC and E. coli in food industry."

Microbiological safety and quality of Mozzarella cheese assessed by the microbiological survey method

Dairy products are characterized by reduced shelf life because they are an excellent growth medium for a wide range of microorganisms. For this reason, it is important to monitor the microbiological quality of dairy products and, in particular, the total viable count and concentration of Escherichia coli, as they are indicators of the hygienic state of these products. In addition, in dairy products such as Mozzarella cheese, it is important to monitor the concentration of lactic acid bacteria (LAB), as they are the major components of starter cultures used in cheese production, contributing to the taste and texture of fermented products and inhibiting food spoilage bacteria by producing growth-inhibiting substances. For these reasons, to ensure the quality and safety of their products, cheese makers should monitor frequently, during fresh cheese production, the concentration of LAB and spoilage bacteria. However, usually, small- to medium-size dairy factories do not have an internal microbiological laboratory and external laboratories of analysis are often too expensive and require several days for the results. Compared with traditional methods, the microbiological survey (MBS) method developed by Roma Tre University (Rome, Italy) allows faster and less-expensive microbiological analyses to be conducted wherever they are necessary, without the need for a microbiological laboratory or any instrumentation other than MBS vials and a thermostat. In this paper, we report the primary validation of the MBS method to monitor LAB concentration in Mozzarella cheese and the analysis, using the MBS method, of total viable count, E. coli, and LAB concentrations in the production line of Mozzarella cheese as well as during the shelf life of the product stored at 20°C. The results obtained indicate that the MBS method may be successfully used by small- to medium-size dairy factories factories that do not have an internal microbiological laboratory. Using the MBS method, these dairy factories can monitor autonomously the microbiological safety and quality of their products, saving both time and money

A New Method For Microbiological Analysis That Could Be Used For Point-Of-Care Testing (POCT)

""Abstract: Standardized microbiological methods used in clinical analysis are based on traditional microbial enrichment. on selective media, possibly followed by characterization of bacteria with molecular methods. These techniques present. several difficulties, such as the subjectivity in the interpretation of genetic, biochemical or morphological tests and the. possible interference of biological matrices, specially when low levels of contamination are present. In addition, standardized. microbiological analyses are characterised by the high cost of the method, both in terms of labor and supplies, and. above all, by the long time needed to obtain definitive results (from 3 to 7 days). These reasons have led to the development. and refinement of microbiological POCTs which are now available for several microorganisms, even thought no microbiological. POCT was up to now developed for the count of total viable bacteria (TVC) in serum, urine or other biological. fluids.. MBS srl (a spin-off of Roma Tre University, Rome, Italy) has developed and patented an alternative method for selective. counting of bacteria, called Micro Biological Survey (MBS) method. The MBS method is based on colorimetric survey. performed in mono-use disposable reaction vials in which samples can be inoculated without any preliminary treatment.. The analyses can be carried out by untrained personnel and anywhere they are necessary, without the need for any other. instrumentation than a thermostated optical reader that can automatically detect the colour change providing the number. of bacteria present into the sample. The MBS method measures the catalytic activity of redox enzymes in the main metabolic. pathways of bacteria, allowing an unequivocal correlation between the observed enzymatic activity and the number. of viable cells present in the samples. The time required for a color change is inversely related to the log of bacterial concentration;. like an enzymatic reaction, the greater the number of bacteria, the faster the color change.. The objective of this study was the primary validation, in accord with ISO 13843:2003 (Guidance on validation of microbiological. methods), of the quantitative Micro Biological Survey (MBS) method for Total Viable Count (TVC). Validation. aims to compare the results obtained with an alternative method, in this case the MBS method, with the results obtained. with the reference method. To verify the equivalence between the two methods different parameters were analyzed:. selectivity, linearity and accuracy. The validation has shown that the MBS method gives similar results and is in agreement. with the reference methods. The MBS method could therefore represent a worthy aid in microbiological analysis as. POCT device without replacing the analysis carried out with traditional methods which are very precise though often long. and complex."

A new device for the prompt diagnosis of urinary tract infections

BACKGROUND: Urinary tract infections (UTIs) are among the most common infectious diseases. RESULTS obtained from conventional microbiological analysis of urine and antibiotic susceptibility testing are available only after a few days, delaying precise diagnosis and appropriate therapy. Micro Biological Survey (MBS) srl (a spin-off of Roma Tre University, Rome, Italy) has developed and patented an automated colorimetric test for rapid bacterial counting. In a preliminary validation study it was demonstrated that the results obtained with the MBS method are equivalent to the results obtained with conventional culture-based microbiological analysis. METHODS: In this study, sterile urine samples were artificially contaminated with bacterial species that are most frequently responsible for UTIs. The MBS method was used to evaluate the presence of bacteria and their sensitivity to some of the most commonly used antibiotics in UTIs. RESULTS: The MBS method was able to detect in a few hours the presence or absence of bacteria at clinically significant concentrations (>105 CFU/mL), and to provide their susceptibility pattern to a limited panel of antibiotics. DISCUSSION: The results obtained demonstrate that the MBS point-of-care testing (POCT) device could be developed into a valuable aid for the management of UTIs, possibly addressing more precise diagnosis and appropriate therapy

A new device for the prompt diagnosis of urinary tract infections.

Background: Urinary tract infections (UTIs) are among the most common infectious diseases. Results obtained from conventional microbiological analysis of urine and anti-biotic susceptibility testing are available only after a few days, delaying precise diagnosis and appropriate therapy. Micro Biological Survey (MBS) srl (a spin-off of Roma Tre University, Rome, Italy) has developed and patented an automated colorimetric test for rapid bacterial counting. In a preliminary validation study it was demonstrated that the results obtained with the MBS method are equivalent to the results obtained with conventional culture-based microbiological analysis. Methods: In this study, sterile urine samples were artifi-cially contaminated with bacterial species that are most frequently responsible for UTIs. The MBS method was used to evaluate the presence of bacteria and their sen-sitivity to some of the most commonly used antibiotics in UTIs. Results: The MBS method was able to detect in a few hours the presence or absence of bacteria at clinically significant concentrations ( >  105 CFU/mL), and to provide their sus-ceptibility pattern to a limited panel of antibiotics. Discussion: The results obtained demonstrate that the MBS point-of-care testing (POCT) device could be devel-oped into a valuable aid for the management of UTIs, pos-sibly addressing more precise diagnosis and appropriate therapy