摘要:

Summary:A proprietary powder containing 10% by weight of spores of bacteria pathogenic for insects has been shown to kill the larvae of the flour moth. In wholemeal flour, between 0.1 and 0.3% by weight of the powder completely prevented the development of infestation by newly‐hatched larvae. Infestations of wholemeal flour in sheds were checked considerably by the application of surface deposits of the spores, established by dusting the dry powder or spraying a suspension in wate

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01974.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:In the course of field experiments designed to ascertain the main causes of pollution in shallow wells and the more important remedial measures which can be adopted, experimental renovations carried out on three shallow wells, all of poor hygienic quality, brought about a marked improvement in potability. The main items of renovation and construction concerned the use of correct waterproofing methods, and the sealing of the well orifice against surface seepage. Cemented concrete blocks and pre‐cast concrete cylinders provided adequate waterproofing for the first 10–14 ft. of the well shaft.Data obtained from a survey of 48 shallow wells in Northern Ireland sunk or renovated during the past two years, indicate the general ability of such wells to supply water of satisfactory quality, providing due care is taken in construction and siting to prevent the infiltration of surface wa

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01975.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:Solid carbon dioxide is recommended as a refrigerant for samples of ice‐cream whileen routeto the laboratory in insulated boxes. Ice‐cream mix should be heated to a temperature of 165° F. for a minimum of 10 min. The gravimetric sampling method appeared to be more accurate than the volumetric method in the routine bacteriological examination of ice‐cream. During ageing of pasteurized icecream mix at 34–37° F. the bacterial content decreased, but as the results were obtained on the product of one manufacturer only, further work is needed on this point. The methylene blue reduction time was sometimes unduly short in view of the bacterial content and it is suggested that this test should be used only for screening purposes and that the colony count and coli‐aerogenes tests are still the best measures of the hygienic quality o

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01976.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:About 20% of water samples examined 20 hr. after sampling, this period including 18 hr. storage at 3–5°, had coli‐aerogenes andBact. colicontents significantly lower than those determined after 2 hr. at air temperature. Samples with over 50 such organisms/100 ml. at the earlier testing time seldom showed an increased content after refrigeration overnight. The results of statistical analysis of the data confirmed the findings of other workers that coli‐aerogenes bacteria are less abundant in samples of water stored before analysis. Colony counts at 37° and 22° did not reflect this reduction in

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01977.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:Ex‐farm milk rejections from a large dairy in the Home Counties have been reviewed, and a detailed analysis made for the period October 1948‐September 1949. A number of samples rejected on taint but otherwise satisfactory were also subjected to the 30 min. resazurin and Breed count tests. The methods of a group of producers invariably sending acceptable milk have been examined in an attempt to discover a common factor which could account for their high standard. It is concluded that with existing methods of transport and daily reception the supply of acceptable milk is possible, that this is within the control of the producer, and that the objective laboratory tests at present available cannot entirely replace smell for determining the acceptability of m

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01978.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:To define a suitable technique for estimating thermoduric bacteria in raw milk supplies, experiments were made to determine whether any difference could be detected between colony counts after laboratory pasteurization at 145 or 150° F. (62.8 or 65.5°) and whether colony counts are affected by temperature and period of storage of samples before laboratory pasteurization. Temperatures above 63.5±0.5° occasionally gave underestimates of the thermoduric population. Within limits time and temperature of storage generally had no effect on numbers of thermoduric bacteria and samples to be examined for thermoduric content can be aged at temperatures between 4 and 20° and examined at any time up to 24–26 hr.It is recommended that the pasteurizing bath shall be capable, under working load, of heating the samples to 63.5° within 5 min. To ensure this with certain types of bath it may be necessary to circulate the water, or to avoid overloading.A limited study of types of thermoduric organisms predominating after different incubation periods and temperatures of storage revealed that the type initially predominant was generally present in greatest numbers after the milk had been aged for 24 hr. Occasionally Gram‐positive sporing rods overgrew other types and some micrococci were not favoured by stora

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01979.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:A standard method for the application of the laboratory pasteurization test for milk, and rinses and swabs of dairy equipment, is described. The interpretation of the thermoduric colony counts so obtained is discussed, and tentative advisory standards are suggested.

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01980.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:After soil burial of sisal rope and baler twine treated with a water repellent, the aerobic microflora was examined. Ten fungi and 71 bacteria capable of growth on an inorganic basal medium with the water repellent as the sole source of organic carbon were isolated. Six of the fungi were penicillia. All the bacteria were rod shaped and all except five were Gram‐negative; they comprised members of the generaPseudomonas, Alcaligenes, BacteriumandAchromobacter, in decreasing numerical order.In studies of the interactions between the bacteria and the ten fungi on potato dextrose agar, bacteria actively suppressed fungal growth in only 9% of cases, the most readily inhibited fungus of the cultures studied thoroughly being a member of the genusPaecilomyces.Fungi completely overgrew the bacteria in 34% of cases, the most aggressive fungus being aPenicillium.In the remaining 57% of tests neither bacterium nor fungus was seriously affected by the other. The fungi did not suppress one another.The reduction in mean tensile strength of single fibres taken from waterproofed baler twine was not significantly different from that of fibres from untreated twine, after soil burial for 7 days at 30

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01981.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:With unglazed porcelain or diatomaceous earth candle filters the bubble‐pressure test proved a reliable index of efficiency. A minimum of about 17 lb./in.2was necessary to ensure sterile filtrates over periods of 6–7 hr. Variations in wall thickness did not affect the ultimate efficiency of the filter, but only influenced the delay in passage of organisms. Some degradation of low bubble‐pressure filters resulted from repeated sterilization and use; high bubble‐pressure filters did not behave in t

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01982.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY

摘要:

Summary:Some of the chief methods used in the screening of new compounds against tuberculosis are briefly reviewed. Streptomycin,p‐aminosalicylic acid,p‐acetamidobenzaldehyde thiosemicarbazone,p‐ethylsulphonylbenzaldehyde thiosemicarbazone andp‐anisaldehyde thiosemicarbazone have been tested against mice infected intracerebrally and the results compared with those obtained using the ordinary guinea‐pig test. All were active in mice and all exceptp‐anisaldehyde thiosemicarbazone in guinea‐pigs. A suitable strain of mice is essential and a Table is given showing the susceptibility of several strains to tubercle bacilli inoculated in

ISSN:0370-1778    

DOI:10.1111/j.1365-2672.1950.tb01983.x

出版商:Blackwell Publishing Ltd    

年代:1950

数据来源: WILEY