摘要:

SUMMARY:A study of the bacteria from the surfaces of roots of subterranean clover (T. subterraneumL.) and Wimmera rye‐grass (L. rigidumGaud.) revealed that 21 genera were represented among the isolates from clover and 16 genera among those from rye‐grass. Bacteria showing branched forms predominated and accounted for 63% of the 151 clover isolates and 78% of the 167 grass isolates. Most of these were identified asArthrobacter, but from clover a significant proportion wereNocardia‐like types. Members of the generaMycoplana, Micromonospora, Mycobacterium, andMycococcuswere also identified among the branching forms.Although the soil had been inoculated with effective rhizobia and the clover plants were effectively nodulated only one of the 318 isolates was capable of nodulating subterranean clover. The majority of the isolates were chromogenic and Gram‐negative, produced acid from glucose and ammonia from peptone, were catalase‐positive and grew best aerobically. Approximately half the isolates liquefied gelatin and produced hydrogen sulphide fro

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1959.tb04613.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1959.tb04614.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SUMMARY:Studies of growth curves of enterobacteria in selenite broth containing different carbohydrates showed that whereas mannitol and lactose brought about a steep fall in coli‐aerogenes bacteria, mannitol improved the growth ofSalm. typhi‐murium. With mixed cultures ofCit. freundiiI andSalm. typhi‐muriumthe presence of lactose, utilizable by the former, adversely affected the viable count of the latter.Comparative studies with routine faeces specimens showed that selenite broth was an efficient selective medium with MacConkey's agar; but much better results were obtained when it was combined with deoxycholate‐citrate agar. Gentian violet introduced into selenite broth improved its selectivity for mostSalmonellatypes when MacConkey's agar was used for final is

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1959.tb04615.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SUMMARY:Experiments were designed to determine the effect of freezing and storage on the bacterial population of pasteurized milk. Samples taken on separate occasions sometimes reacted differently to freezing treatment. Significant changes in bacterial numbers occurred after the frozen milk had been stored for 4–5 months at −12°, and this coincided with definite physical changes in the milk. Known numbers of coliaerogenes organisms were added to the pasteurized product in order to study their behaviour when frozen and stored at low temperatures. The counts were significantly lower after storage for 4 mo

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1959.tb04616.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SUMMARY:In a survey of milk obtained from individual farms and creameries, 87% of samples were found to contain fewer than one cell ofBacillus cereus/ml. The remaining 13%, although they all yielded low counts, showed that the organism tended to occur in milk received from particular farms and creameries. On investigating sources of contaminated milk, it was found that the organism was derived chiefly from cans which, after being emptied of milk, had been allowed to stand for a long time before being washed properly and ‘sterilized’. The vegetative cells ofB. cereuswere shown to form spores readily in thin films of diluted milk, such as may occur in a rinsed

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1959.tb04617.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SUMMARY:Comparisons are given of the output of sorbose from 3 litre cultures ofAcetobacter suboxydansgrown in a sorbitol medium in batch and continuous culture. An estimate is given of the investment value of a continuous process of sorbose production relative to the batch process.

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1959.tb04618.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SUMMARY:The tests for faecal contamination in foods, based on ‘indicator species’, should be reconsidered for the following reasons. First, in Europe,Escherichia coliis regarded as a specific index of such contamination; but, apparently through the use of antibiotics, the proportion of human faeces containingKlebsiellahas risen from 5.2% in 1947 to 48.4% in 1956–7. Moreover,E. coliand other coli‐aerogenes organisms may be absent from the gut of certain animals, notably the pig. Second, while the usual methods of counting coli‐aerogenes bacteria do not permit the isolation of strains which ferment lactose slowly or not at all (i.e. paracolons), these occur in 35.6% of samples of human faeces. Further, the recommended methods of detecting such strains are not wholly satisfactory. Third, the origin of the coli‐aerogenes bacteria is uncertain.It is thus necessary to consider other organisms which normally inhabit the intestinal tract of humans and other animals. As toClostridium perfringens, its source is doubtful, for it may come from faeces or from soil, and many foods contain only soil strains. The group D streptococci, on the other hand, are excellent indicators of faecal contamination. They are constant or frequent in the intestines of man and animals, and often more numerous there than coli‐aerogenes bacteria. Their specificity as an index of faecal contamination is high and their investigation is easy with the selective media now available. Associated with the coli‐aerogenes bacteria, they justify the diagnosis of faecal contamination

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1959.tb04619.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

SUMMARY:In this paper some of the physical processes occurring when cotton articles are sterilized in metal drums or bare packages in an autoclave are discussed, with special reference to the case where a good vacuum is drawn before the admission of steam. It is shown that under these conditions the heating will be quick, uniform, regular and reversible, and that no separate drying‐off period should be needed. Calculation of the temperatures and moisture contents reached during the ‘quasiequilibrium’period shows that the ‘superheating’of the cotton is self‐limiting, can never exceed a few degrees Centigrade, and will not give rise to serious weakening of the cotton. Calculation of the rate of irreversible penetration of moisture into the contents of the drum shows that this can easily be limited to the wrapping layer. Information is given on the ‘heat‐tendering’of cotton, and the advantages of using a good vacu

ISSN:0021-8847    

DOI:10.1111/j.1365-2672.1959.tb04620.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY