Indirect conductimetry: a novel approach to the conductimetric enumeration of microbial populations

Owens, J.D.; Thomas, David B.; Thompson, Paul; Timmerman, W. A.

doi:10.1111/j.1472-765x.1989.tb00337.x

Cited by 77 publications

(42 citation statements)

References 5 publications

(3 reference statements)

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“…TSB was used as growth medium for detection of P. aeruginosa and E. coli whereas brain heart infusion broth (Oxoid CM225) was used for detection of Staphylococcus spp. The growth of P. aeruginosa was measured by the indirect conductance measurement (16)(17)(18), and the growth of E. coli and Staphyolococcus spp. was measured by the direct conductance method (16).…”

Section: Methodsmentioning

confidence: 99%

Microbial survival and odor in laundry

Munk

Johansen

Stahnke

et al. 2001

J Surfact & Detergents

137

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detergents were determined in laboratory wash experiments. Four test strains-Staphylococcus epidermidis, S. aureus, Escherichia coli, and Pseudomonas aeruginosa-were evaluated on cotton textile. A significant survival and transfer between textiles were found for all four test strains washed in E.U. and U.S. color detergents (without bleach), whereas no survival was observed in bleach-containing detergents. Gram-negative strains generally survived in greater numbers than Gram-positive strains. A greater survival was observed in U.S. detergents at U.S. conditions (30°C, 12 min) than in E.U. detergents at E.U. conditions (40°C, 30 min). The adhesion of odorants to cotton and polyester textiles during washing and drying was studied using six previously identified odorants in laundry [ethylbutanoate, (Z)-4-heptenal, (E)-2-nonenal, 3-methylbutanoic acid, 2-methoxyphenol (guaiacol) and 4-methyloctanoic acid]. All odorants were effectively removed from cotton during wash, whereas the odorants were more strongly associated with polyester fibers. During wash, hydrophobic odorants [(Z)-4-heptenal, (E)-2-nonenal, and guaiacol] adhered more strongly to polyester than the acids. The odor formed by surviving skin microflora attached to textiles soiled with human sebum and sweat after laundering at 30°C was studied by sensory evaluation and aroma extract dilution analysis. Intensive odor was formed in both cotton and polyester textiles during prolonged drying. Generally, the odor formation in cotton swatches and the bacterial count of the wash liquor from cotton swatches were greater than the odor formation and bacterial count from polyester swatches. Odorants with animal notes (branched fatty acids) dominated the odor profile after prolonged drying. Polyester swatches possessed a more complex odor profile than cotton; in particular, aldehydes were more dominating in polyester than in cotton. A high-impact and malodorous component, 3-methylindole, was formed during prolonged drying in cotton. The study demonstrates that microbial odor formation is a dominating factor determining the odor impression of laundered cotton and polyester textiles dried under slow drying conditions. The initial soiling with aromatic components has an additional impact on the odor profile of polyester textiles after wash, due to strong adherence of odorants during the wash cycle. a RI, retention index; FD, flavor dilution; ND, not determined, but a tentative identification is suggested by means of results with two different capillary GC columns, DB-FFAP and DB-5 (see Experimental Procedures section). b Identification based on comparison with the reference compound using the following criteria: 1 RI on the FFAP and DB-5 capillaries, mass spectra in the electron impact mode, and odor quality at the sniffing port (identified in Ref. 14). 2 Criteria described under footnote b,1 but not identified previously in Reference 14. 3 RI on two capillaries, mass spectra in the chemical ionization mode, and odor quality at the sniffing port (identified in Ref. 14). 4...

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Section: Methodsmentioning

confidence: 99%

Microbial survival and odor in laundry

Munk

Johansen

Stahnke

et al. 2001

J Surfact & Detergents

137

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“…An indirect technique was employed based on the measurement of variations in impedance in a 0.2% KOH solution caused by absorption of the CO 2 produced during fermentation (Owens et al 1989;Ribeiro et al 2003) using a lTrac 4200 impedance analyser (SY-LAB Instruments).…”

Section: Yeast Vitalitymentioning

confidence: 99%

Enological properties in wild and commercial Saccharomyces cerevisiae yeasts: relationship with competition during alcoholic fermentation

Barrajón

Arévalo‐Villena

Úbeda

et al. 2011

World J Microbiol Biotechnol

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Commercial yeasts are widely used in winemaking to carry out the alcoholic fermentation; nevertheless, some wild strains may compete with them and even dominate the process. In this research, 21 prevailing wild strains isolated from inoculated musts were chosen in order to study the competition between them and commercial yeasts. Some biotechnological properties which could enhance their performance during the process were also studied, such as vitality, killer factor, resistance to high concentrations of sugar, ethanol and SO 2 or trehalose and glycogen cell content. All yeasts, both commercial and wild strains, showed resistance to the killer toxin and they were all able to growth under adverse conditions. However, vitality and carbohydrate content were strain dependent in around 70% of the cases; the wild strain had a higher vitality and accumulated less trehalose than its commercial counterpart.

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“…For control experiments, the volume of the omitted constituents was replaced with HEPES buffer. The numbers of attached live cells on the lenses were determined after treatment by using indirect conductance measurements (2,6,11,19,33) with the Flexi 2000 instrument (Malthus Instruments Ltd., West Sussex, United Kingdom). In brief, the lenses were placed in Malthus glass tubes containing 3 ml of tryptone soy broth, and an insert with 0.5 ml of 0.1 N KOH was placed in each tube.…”

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confidence: 99%

Curvularia Haloperoxidase: Antimicrobial Activity and Potential Application as a Surface Disinfectant

Hansen

Albertsen

Schäfer

et al. 2003

Appl Environ Microbiol

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A presumed antimicrobial enzyme system, the Curvularia haloperoxidase system, was examined with the aim of evaluating its potential as a sanitizing agent. In the presence of hydrogen peroxide, Curvularia haloperoxidase facilitates the oxidation of halides, such as chloride, bromide, and iodide, to antimicrobial compounds. The Curvularia haloperoxidase system caused several-log-unit reductions in counts of bacteria (Pseudomonas spp., Escherichia coli, Serratia marcescens, Aeromonas salmonicida, Shewanella putrefaciens, Staphylococcus epidermidis, and Listeria monocytogenes), yeasts (Candida sp. and Rhodotorula sp.), and filamentous fungi (Aspergillus niger, Aspergillus tubigensis, Aspergillus versicolor, Fusarium oxysporum, Penicillium chrysogenum, and Penicillium paxilli) cultured in suspension. Also, bacteria adhering to the surfaces of contact lenses were killed. The numbers of S. marcescens and S. epidermidis cells adhering to contact lenses were reduced from 4.0 and 4.9 log CFU to 1.2 and 2.7 log CFU, respectively, after treatment with the Curvularia haloperoxidase system. The killing effect of the Curvularia haloperoxidase system was rapid, and 10 6 CFU of E. coli cells/ml were eliminated within 10 min of treatment. Furthermore, the antimicrobial effect was short lived, causing no antibacterial effect against E. coli 10 min after the system was mixed. Bovine serum albumin (1%) and alginate (1%) inhibited the antimicrobial activity of the Curvularia haloperoxidase system, whereas glucose and Tween 20 did not affect its activity. In conclusion, the Curvularia haloperoxidase system is an effective sanitizing system and has the potential for a vast range of applications, for instance, for disinfection of contact lenses or medical devices.

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Indirect conductimetry: a novel approach to the conductimetric enumeration of microbial populations

Cited by 77 publications

References 5 publications

Microbial survival and odor in laundry

Microbial survival and odor in laundry

Enological properties in wild and commercial Saccharomyces cerevisiae yeasts: relationship with competition during alcoholic fermentation

Curvularia Haloperoxidase: Antimicrobial Activity and Potential Application as a Surface Disinfectant

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