Experiments with a view to utilising the isolated species. 



It "would be natural, of course, to test our lactic acid bacteria in practice at the places 

 from where they were isolated. There is no doubt, for instance, that the loss of dry matter 

 in souring of potatoes, beets and other fodder could be reduced considerably if the gas 

 developing bacteria there abounding could be at once subdued by rich inoculation with 

 such lactic acid bacteria as thrive well in the vegetable matter concerned. Experiments 

 on a large scale in this direction Were also planned by me in co-operation with the State 

 Plant Cultivation Committee („Planteavlsudvalg") but Were relinquished for the time 

 being owing to scarcity of fodder. 



We have attained some extremely favourable results with sour cabbage, at the 

 Ama preserving factory. Cabbage inoculated with Be. arabinosaceus No. 19 and Sbm. 

 plantarum No. 37 developed a much better aroma and was more tender than cabbage 

 which had soured spontaneously. 



Under the heading of Sc. ciemoris I have given several hints which will be of value 

 in the production of starters for souring of cream. 



Particularly interesting are the cheese bacteria, and it was indeed the desire to 

 study these further which led to the undertaking of the present work. Simultaneously 

 with our bacteriological investigations therefore, we have carried out a great number 

 of cheese-making experiments, in order to ascertain the effect produced in cheese by the 

 bacteria found in cheese — and especially in Danish dairy cheese. 



The experiments were carried out wdth sterile apparatus and with so called iced 

 milk from "The Copenhagen Milk Supply". The milk Was previously partly freed from 

 germs, either by heating for. half an hour at 70°, in the cheese vat itself, or by twenty four 

 hours' treatment with 1.5 % hydrogen peroxide at 50° in an acid demijohn. The surplus 

 of hydrogen peroxide Was removed, immediately before adding the rennet, by means 

 of Hepin, an extract of ox liver, containing catalase, placed on the market by the Beh- 

 ring Works, at Marburg. By this latter method, previously employed by Gerda Troili- 

 PETERSS0Ni),the power of the milk to coagulate with rennet is less impaired, but the milk 



M Centralblatt f. Haktcriologie. II. Abt. 1909, Bd. 24, p. 343, According to our investigations, nearly 

 1 " ,0 HiOj must be added to the mili< in order constantly to prevent the development of yeast and 

 bacteria. The hydrogen peroxide does not, however, impede the action of the proteolytic enzymes in 

 the milk, and milk to which hydrogen p^oxide has been added will therefore curdle in the course of 

 2-3 weeks, and then again dissolve. After six months, milk with 2" .oHiOj was foun.1 to contain 

 79 "lo SN and 10.5 «io DN. 



