摘要:

SUMMARYThe heat resistance of spores ofBacillus subtilisstrain Bac 1–11, isolated from processed fried rice, and strain Bac 1–12, isolated from processed evaporated milk, has been determined. The calculatedD112.5of spores of Bac 1–11, inM/40 phosphate buffer (pH 6.8) and in fried rice (pH 6.4) was 4.2 min and 4.5 min (z= 18 and 20 resp.), respectively. The calculatedD112.5of spores of Bac 1–12, in M/40 phosphate buffer (pH 6.8) and in evaporated milk (pH 6.4) was 5.0 min and 6.7 min (z= 18 and 23 resp.), respectively. The extrapolatedD121values were 0.57, 0.76, 0.71 and 1.45 min, respe

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00319.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYThe initiation of vegetative growth by spores in Reinforced Clostridial Medium (RCM) adjusted to different water activities (aw) by the addition of NaCl or glycerol does not depend solely on the awof the medium; minimum awat which spores ofCl. botulinumtypes A, B and E could initiate growth were higher in the media containing NaCl. The minimum awat which vegetative cell inocula could grow were similar to those at which spore inocula could initiate growth. The combined effect of lowering the pH and awof the medium was to increase the minimum at which spores of types A and E could germinate and also increase the minimum at which spore and vegetative cell inocula ofCl. botulinumtypes A, B and E could initiate growth.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00320.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYThe commoner mesophilic clostridia have been screened for sporulation in several meat and other media. A method employing enriched spent medium has also been evaluated. A cooked meat medium based on Hartley's digest broth supported sporulation of more species than any other medium examined.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00321.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYThe fine structure ofClostridium sporogenesandCl. bifermentansusing ultrathin sectioning is described. The location of esterases during various stages of sporulation is related to the fine structure, together with the location of surface antigens using the ferritin labelled antibody technique.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00322.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYThe degree of sporulation exhibited by yeasts was greatly influenced by cell population density (CPD). In general, optimal sporulation occurred over a narrow range of low CPD values for solid and liquid media. On acetate agar, however, optimal sporulation was obtainable over a wide range of CPD values above a certain, usually low, threshold. There is evidence that on this medium, the effect of CPD is due to a small but critical requirement of CO2for sporulation. Addition of potassium improved sporulation in the presence of acetate and pyruvate, but there was little effect with glucose. Nitrogen compounds and yeast extract tended to delay and depress sporulation in the presence of acetate. Most yeasts sporulated best on acetate agar at pH 8.4‐10.6 irrespective of CPD; a high pH was also necessary for optimal sporulation on glucose agar, but its value depended on glucose concentration and CPD. Buffering of pyruvate and glucose agar was necessary for the best results, but it was not usually needed for acetate media, the pH of which rose rapidly after inoculation to the optimal range. Glucose, pyruvate and, in particular, acetate, all proved capable in general of inducing a higher degree of sporulation than was possible, under the best conditions, in their absenc

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00323.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYHarvested and stored fruit, and juice collected from the cider press, showed larger numbers and a wider range of yeast species than did fruit picked aseptically from the tree. The ratios of species changed during storage. Under clean factory conditions or in the pilot plant the range of species was limited.Saccharomycesspp. and other spore‐formers were absent, possibly having been eliminated by thorough cleaning of equipment.Kloeckeraspp. which increased markedly on the fruit during harvesting and storage, remained as an appreciable component of the juice microflora. Factories with less rigid standards of sanitation harboured a much wider range of yeasts.Saccharomycesspp. and extraneous sporeformers, which were rarely detected on the whole fruit, appeared in the freshly pressed juice, and together withKloeckeraspp., made up a large proportion of the microflora. The undesirable sporeforming spp.,SaccharomycodesandHansenula, were detected in some instance

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00324.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYThe interaction between aqueous solutions of radioactive iodine (131I) and washed suspensions ofEscherichia coliandStaphylococcus aureushas been investigated. The conditions of the experiments were such that the bacteria were killed and no free iodine remained. Most of the iodine reacted with the bacteria by an oxidation‐reduction process, but halogenation also took plac

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00325.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYA double layered plating procedure has been adapted for the determination of lipolysis by micro‐organisms. The base layer is prepared by mixing any fat, oil or triglyceride with Victoria Blue B and agar in a blender. Layers 2–3 mm thick are poured, allowed to solidify and overlaid with a suitable nutrient medium. This procedure allows considerable flexibility in the choice of fat as well as of nutrient medium. If lipolytic counts are desired, dilutions can be placed on the surface of the base layer prior to pouring the nutrient medium. Data are presented to show that no single fat or nutrient medium is suitable for all micro‐organisms. Acid production from carbohydrates in the medium rarely caused confusion in recognizing lipo

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00326.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYA sterile disposable plastic Petri dish is described that is divided internally into 25 separate wells. It is designed for use with multipoint inoculators, and allows many commonly used tests to be performed quickly and cheaply. It can also be used for making aseptic serial dilutions.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00327.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYA method is described by which all surface organisms are washed off into a sampling diluent.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1967.tb00328.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY