摘要:

SUMMARY:Methods for determining theBacillus cereuscontent of milks and of rinses of dairy equipment are described and their limitations discussed. Milk samples from various sources were examined throughout the year for ‘bittiness’ as well as forB. cereus.The organism was not detected in all samples showing bittiness. There was a marked seasonal variation in theB. cereusindex of raw milk supplies; maximum numbers were obtained from July to September and minimum numbers in April and May. Rinses of farm dairy equipment yielded fewB. cereusspores but milk cans not uncommonly contained large numbers, especially in the summer months, when 10·5% of cans showed more than 5 × 103/can. Preliminary observations on other sources ofB. cereusare described and some of the problems of the control of this organism in raw milk supplies are disc

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00116.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00117.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY:The application of a radial mechanical shaft seal, and other improvements to a 2–3 1. capacity culture vessel, are describe

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00118.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY:Counts ofEscherichia coliwere done on nutrient agar (control), on membrane filters on nutrient agar and on membrane filters on filter paper pads. With untreated bacteria counts were similar under all conditions, though membrane filters on nutrient agar tended to give slightly low counts. Phenol treated bacteria gave much lower counts when membrane filters were used: the mean counts for 3 strains of the test organism with filters on nutrient agar varied from 35–65% of the control, while counts with filters on filter paper pads were somewhat lower, varying from 30–47% of the control. The low counts on membrane filters on filter paper pads were not due to adsorption of phenol by the filters or to a low concentration of nutrients in the growth med

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00119.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY:Forty‐seven cultures of yeasts, isolated from 47 packs of spoiled acetic acid preserves including 11 varieties and originating from nineteen manufacturers, have been identified according to the system of Lodder&Kreger‐van Rij. Forty‐three cultures had the characteristics ofSaccharomyces acidifaciensand four those ofPichia membranaefa

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00120.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY:When sweet pea seeds were soaked in mercuric chloride solution a considerable quantity of mercury was taken up and was not removable by a washing procedure even more thorough than that usually employed in the technique for the surface sterilization of plant tissues. To remove the bulk of it, soaking the seed for 48 hr was needed.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00121.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY:A medium is described by means of which cells ofBacillus cereusin milk may be estimated without the prior use of a heat treatment. Into a nutrient agar are incorporated: egg yolk, to demonstrate production of the characteristic opacity; citrate, to render the inoculated medium more transparent; lithium chloride and polymyxin, to reduce the growth of other bacteria. A cover of water agar limits the development of certain spreading organisms. The medium has proved of value in a survey of samples of raw milk, providing information additional to that obtained by plating after a heat treatment.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00122.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY:The modification of the 44° test proposed by Mackenzie, Taylor&Gilbert (1948) is useful for the rapid identification ofEscherichia coliI in water and foods. False positive tests caused by other coli‐aerogenes bacteria, or by their association with other organisms, can be considered rare. Only a fewE. coliI fail to produce indole or ferment lactose at 44°, and further confirmation for routine purposes is necessary only when the results at 44° are discordant, e.g. indole positive‐lactose negative or indole negative‐lactose

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00123.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY:A study has been made of the immersion cleaning technique as applied on commercial farms. In an initial survey bacteriological results for rinses and swabs of the milking equipment were satisfactory on most farms, but on one farm the results were very disappointing. Further investigations at this farm showed that the poor results were caused partly by sporing bacteria which survived the caustic soda treatment, presumably in the spore state, and partly by non‐sporing organisms, chiefly chromobacteria and micrococci.These non‐sporing organisms are found in abundance on the surface of dirty wash troughs, and under certain conditions re‐contamination of the milking equipment can occur during the rinsing operation. Suggested modifications to the original immersion cleaning technique include the use of hot water for the before‐milking hypochlorite rinse, brushing the equipment in the after‐milking rinse to remove extraneous dirt, regular cleansing of the wash trough and the monthly cleansing of the baske

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00124.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

SUMMARY:A spore ‘spectrum’ is described of aerobic mesophiles capable of resisting different heat treatments. It is shown thatB. licheniformisis the most common spore former found in bulk milk but since its spores are rapidly destroyed at 100°, the more heat resistantB. subtilisis the dominant surviving spore former in commercial sterilized milk. The thermal resistance of strains ofB. subtilisandB. licheniformisisolated from different sources has been investigated and the strains ofB. subtilistyped according to the behaviour of their spores when heated at 100°. All strains ofB. licheniformiswere destroyed more rapidly by boiling for 2 min than strains ofB. subtilisbut only those strains of the latter which showed some degree of heat activation were more resistant thanB. licheniformis. The ‘resistant’ and heat activated strains ofB. subtilisappear to be sparsely distributed in nature and were only isolated from sterilized milk where the heat treatment applied would tend to eliminate other strains. The spore content of bovine faeces was similar to that in bulk milk and the total spore content varied seasonally, the spore content of faeces being on the average a hundred times greater during indoor feeding than during the period when the cattle were fed outside. A faecal infection of the milk in the ratio of 1:104would infect the milk with spores at about the same concentration as they are found in bulk raw milk, and it is suggested that bovine faeces could be a primary source of spore formers in milk

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1958.tb00125.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY