Search results for "Colony Count"

Can technical, functional and structural characteristics of dental units predict Legionella pneumophila and Pseudomonas aeruginosa contamination?

2011

Legionella pneumophila and Pseudomonas aeruginosa are common colonizers of water environments, particularly dental unit waterlines. The aim of this study was to assess whether the technical, functional and structural characteristics of dental units can influence the presence and the levels of opportunistic pathogens. Overall, 42 water samples were collected from dental units in a teaching hospital in Palermo, Italy, including 21 samples from the 21 taps supplied by the municipal water distribution system and 21 samples from oral rinsing cups at 21 dental units. L. pneumophila was present in 16 out of 21 water samples (76.2%) from dental units, and the median concentration was higher in samp…

The logarithmic transformation should be avoided for stabilising the variance of mould growth rate.

2007

Abstract Radial growth rate, μ (mm d − 1 ) was evaluated by plotting the radius of the colony, r (mm) versus time (d) for Alternaria alternata , Aspergillus flavus , Cladosporium cladosporioides , Mucor racemosus , Rhizopus oryzae and Trichoderma harzianum at different T and a w . For each of the 12 data sets, an analysis of variance of the raw growth rate data was performed. It was observed from the P -values that all square-root transformed values of μ were non-significant at the significance level α  = 0.05, whereas for untransformed values of μ , three of the 12 values were significant and for logarithmically transformed μ , nine of the 12 values were significant at the significance lev…

Synthesis and antifungal activity of new N-(1-phenyl-4-carbetoxypyrazol-5-yl)-, N-(indazol-3-yl)- and N-(indazol-5-yl)-2-iodobenzamides

2002

N-(1-Phenyl-4-carbetoxypyrazol-5-yl)-, N-(indazol-3-yl)- and N-(indazol-5-yl)-2-iodobenzamides 6, with a Benodanil-like structure, were synthesized by refluxing in acetic acid the corresponding benzotriazinones 5 with potassium iodide for 1 h in order to study the role on the antifungal activity of the N-substitution with an aromatic heterocyclic system on benzamide moiety. Among the tested iododerivatives, compounds 6d,f,g,h possess interesting activities toward some phytopathogenic fungal strains.

In vitro antifungal properties of mouthrinses containing antimicrobial agents

1997

The purpose of this study was to investigate the in vitro antifungal properties of seven commercial mouthrinses containing antimicrobial agents. These included cetylpyridinium chloride (CPC), chlorhexidine digluconate (CHX), hexetidine (HEX), sanguinarine (SNG), and triclosan (TRN). The minimum fungicidal concentration (MFC) against six species of yeasts was determined by a broth macrodilution method. The kill-time of mouthrinses at half the concentration of the commercial formulations was also determined. MFCs were achieved with each mouthrinse, except the SNG-containing mouthrinse, against all the organisms being tested. However, the CPC-containing mouthrinse appeared more active than the…

Influence of nitrogen and carbon sources on the production of ochratoxin A by ochratoxigenic strains of Aspergillus spp. isolated from grapes.

2008

This work studies the influence of nitrogen and carbon source on ochratoxin A production by three Aspergillus isolates A. ochraceus (Aso2), A. carbonarius (Ac25) and A. tubingensis (Bo66), all isolated from grapes. A basal medium (0.01 g/l FeSO4.7H2O, 0.5 g/l MgSO4.7H2O, 0.5 g/l Na2HPO4.2H2O, 1.0 g/l KCl) was prepared. This medium was supplemented with different nitrogen sources, both inorganic [(NH4)3PO(4), 0.3 g/l plus NH4NO3, 0.2 g/l] and organic (histidine, proline, arginine, phenylalanine, tryptophan or tyrosine) at two concentrations (0.05 g/l or 0.3 g/l), and different carbon sources (sucrose, glucose, maltose, arabinose or fructose) at three concentrations (10 g/l, 50 g/l or 150 g/l…

Application of propidium monoazide-qPCR to evaluate the ultrasonic inactivation of Escherichia coli O157:H7 in fresh-cut vegetable wash water.

2012

The efficacy of sanitizing technologies in produce or in vegetable wash water is generally evaluated by plate count in selective media. This procedure is time consuming and can lead to misinterpretations because environmental conditions and sanitizing processes may affect bacterial growth or culturable capability. Thus, the aim of this study was to determine the applicability of a propidium monoazide real-time PCR (PMA-qPCR) method to monitor the inactivation by ultrasound treatment of foodborne bacteria in fresh-cut vegetable wash water. To this aim, lettuce wash water was artificially inoculated with Escherichia coli O157:H7 (10⁶ CFU/mL) and treated by means of a continuous ultrasonic irr…

Could halophilic archaea improve the traditional salted anchovies (Engraulis encrasicholus L) safety and quality?

2010

Aims: The positive influence of two selected extremely halophilic archaea strains in the production of salted anchovies (Engraulis encrasicolus, L., 1758) was highlighted. Methods and Results: Anchovies produced with salt artificially contaminated with halophiles exhibited lower loads of staphylococci, Enterobacteriaceae and lactic acid bacteria, and a reduced content of histamine as well as an improved organoleptic acceptance. Conclusions: The findings of this survey are expected to enhance the safety of salted anchovies, with regard to the histamine formation during ripening, and to improve the sensory attributes of this product. Significance and Impact of the Study: This study represents…

Evolution of microbiological and chemical parameters during red wine making with extended post-fermentation maceration.

2014

Abstract The aim of the present work was to investigate the microbiological, chemical, and sensory characteristics of red wine subjected to post-fermentation maceration that was extended to 90 days. For this purpose, the ‘Aglianico di Taurasi’ grape was used as a case study. The total yeast concentration increased until day 40 of maceration and decreased thereafter, whereas the concentration of lactic acid bacteria slightly increased. Dekkera/Brettanomyces spp. and acetic acid bacteria were not detected. The yeast community was composed of Saccharomyces cerevisiae, Zygosaccharomyces bisporus, Metschnikowia pulcherrima, Hanseniaspora guilliermondii, Hanseniaspora uvarum, Pichia guilliermondi…

Being candid about Candida airway colonization and clinical outcomes: What can we really learn from unadjusted associations?

2020

Damage in Escherichia coli Cells Treated with a Combination of High Hydrostatic Pressure and Subzero Temperature

2007

ABSTRACT The relationship between membrane permeability, changes in ultrastructure, and inactivation in Escherichia coli strain K-12TG1 cells subjected to high hydrostatic pressure treatment at room and subzero temperatures was studied. Propidium iodide staining performed before and after pressure treatment made it possible to distinguish between reversible and irreversible pressure-mediated cell membrane permeabilization. Changes in cell ultrastructure were studied using transmission electron microscopy (TEM), which showed noticeable condensation of nucleoids and aggregation of cytosolic proteins in cells fixed after decompression. A novel technique used to mix fixation reagents with the c…