The Numerical Interpretation of Fermentation-Tube Results

McCrady, M. H.

doi:10.1093/infdis/17.1.183

Cited by 224 publications

(107 citation statements)

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“…Isolates presumptively identified as salmonella were characterized further by the biochemical tests of Edwards & Ewing (1972) and analysis of somatic and flagellar antigens using slide and tube agglutinations with sera from Burroughs Wellcome (Beckenham, Kent). The most probable number (MPN) of salmonella/g sample was established, with McCrady's (1915) tables, only after the complete characterization of all isolates.…”

Section: Methodsmentioning

confidence: 99%

The incidence and level of contamination of British fresh sausages and ingredients with salmonellas

Banks¹,

Board²

1983

J. Hyg.

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SUMMARYA five-tube most probable number (MPN) method, with pre-enrichment and enrichment stages, was used in a study ofthe incidence ofsalmonella contamination of British fresh sausages and the ingredients used in their manufacture. All samples were taken from a large factory in the course of routine production. There was an incidence of 65 % contamination of pork (n = 20) and 55 % (n = 20) in pork and beef sausages. The incidences of contamination of uncooked ingredients varied from 95 % for mechanically recovered meat (n = 20) to 10 % for another type of meat. Cooked and/or dried ingredients were rarely contaminated with these organisms and, when contamination occurred, coliforms were also important.The numbers of salmonellas isolated ranged from 7-40 for pork sausages, from 8-24 for beef and pork sausages and from 0-8-378 organisms/g for ingredients.The following salmonella serotypes were isolated (ranked in descending order of incidence): S. derby, S. dublin, S. newport, S. stanley, S. typhimurium, S. heidelberg, S. infantis and S. agona.

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Section: Methodsmentioning

confidence: 99%

The incidence and level of contamination of British fresh sausages and ingredients with salmonellas

Banks¹,

Board²

1983

J. Hyg.

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“…Incubations were performed at 28°C, in the dark, for more than eight weeks. Positive wells were assessed by nitrite concentration using Griess reagent ; according to the statistical method of McGrady (1915), the MPN of nitrifying bacteria per mL of sample was determined from computed scores according to Clarke and Owens (1983).…”

Section: Enumeration Of Bacteriamentioning

confidence: 99%

Nitrogen dynamics in the shallow groundwater of a riparian wetland zone of the Garonne, SW France: nitrate inputs, bacterial densities, organic matter supply and denitrification measurements

Sánchez‐Pérez

Vervier

Garabetian

et al. 2003

Hydrol. Earth Syst. Sci.

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This study highlights the role of interactions between surface and sub-surface water of the riparian zone of a large river (the Garonne, SW France). Information is given about the role of surface water in supplying Dissolved Organic Carbon (DOC ) to the riparian zone for nitrate removal processes. The densities of bacteria (up to 3.310 6 cell m L -1 ) in groundwater are strongly conditioned by the water moving during flood events. Total bacterial densities in groundwater were related to surface water bacterial densities. In sediment, total bacteria are attached mainly to fine particles (90 % in the fraction < 1 mm). Spatial variations in organic carbon and nitrate content in groundwater at the site studied are correlated with exchanges between the groundwater and the river, from the upstream to the downstream part of the meander. Total bacterial densities, nitrate and decressing organic carbon concentrations follow the same pattern. These results suggest that, in this kind of riparian wetland, nitrate from alluvial groundwater influenced by agricultural practices may be denitrified by bacteria in the presence of organic carbon from river surface water.

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“…The MPN technique was first introduced by McCrady (30,31) and consists of the incubation of aliquots of sample dilutions with appropriate media at an ideal temperature for the desired organism. After incubation, the aliquots are examined for the presence or absence of growth (with growth indicating the presence of at least one organism in that aliquot).…”

mentioning

confidence: 99%

Determination of Amoebicidal Activities of Multipurpose Contact Lens Solutions by Using a Most Probable Number Enumeration Technique

Beattie¹,

Seal

Tomlinson³

et al. 2003

J Clin Microbiol

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Six multipurpose contact lens solutions [All-in-One, All-in-One (Light), ReNu MultiPlus, Optifree Express, Complete, and Solo-care soft] were tested for their efficacies against Acanthamoeba castellanii trophozoites and cysts by using a most probable number (MPN) technique for amoebic enumeration. Against trophozoites, All-in-One, ReNu Multiplus, and Optifree Express achieved total kill (log reduction of >3) after the manufacturer's minimum recommended disinfection time (MMRDT), with the remaining solutions failing to reach a log reduction of 1. After 24 h of exposure, all solutions proved trophozoiticidal, achieving, with the exception of Complete (log reduction of 3.13), total kill. Against cysts, All-in-One gave a log reduction of >3 within the MMRDT, with all other solutions failing to achieve a log reduction of 1. After 24 h of exposure, All-in-One achieved total kill of cysts (log reduction of 3.74), ReNu MultiPlus gave a log reduction of 3.15, and the remaining solutions reached log reductions of between 1.09 and 2.27. The MPN technique provides a simple, reliable, and reproducible method of amoebic enumeration that depends on simply establishing the presence or absence of growth on culture plates inoculated with a series of dilutions and determining the MPN of amoebae present from statistical tables. By use of this technique, two of the multipurpose solutions tested, ReNu MultiPlus and Optifree Express, demonstrated effective trophozoiticidal activities within the recommended disinfection times; however, only All-in-One proved effective against both trophozoites and cysts over the same time period. This MPN technique, which uses axenically produced trophozoites and mature, doublewalled cysts, has the potential to form the basis of a national standard for amoebicidal efficacy testing of multipurpose contact lens disinfecting solutions.

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The Numerical Interpretation of Fermentation-Tube Results

Abstract: The writer has prepared" table which contains logarithms for the rapid calculation of "most probable numbers," values of the ordinates of the curves for the results N/l N/2 N/3, N/5 and N/10, etc., copies of which he will be glad to furnish upon request.

Cited by 224 publications

References 0 publications

The incidence and level of contamination of British fresh sausages and ingredients with salmonellas

The incidence and level of contamination of British fresh sausages and ingredients with salmonellas

Nitrogen dynamics in the shallow groundwater of a riparian wetland zone of the Garonne, SW France: nitrate inputs, bacterial densities, organic matter supply and denitrification measurements

Determination of Amoebicidal Activities of Multipurpose Contact Lens Solutions by Using a Most Probable Number Enumeration Technique

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