682 DETERIORATION OF SUGAR CRYSTALS IN BULK, 



heating in a flame. The infected bottles are maintained at 37°. 

 In from two to four days the presence of Bac. hvaniformans is 

 shown by the fluid becoming milky. A turbidity of the solution 

 must not be confounded with the opaque milkiness which is 

 characteristic of ievanijormans. At the same time it must be 

 borne in mind that some races produce but a faint opalescence 

 that might easily be mistaken for a turbidity of the solution. In 

 all cases it is advisable to extract a small loop or a tiny drop by 

 means of a sterile looped platinum wire, or a sterile dropping 

 pipette, and infect a fresh bottle. In from 5 to 7 days, when 

 the formation of levan is at a maximum, the second culture could 

 be tested for reducing sugars and also for levan by precipitation 

 with alcohol and subsequent solution in water. 



Of course, the bacteriologist would also test the sugar straight 

 away by preparing plates from saccharose-agar or even ordinary 

 nutrient agar, infected with about 1 grm. of the sample. Any 

 suspicious colony that developed would be picked out, infected 

 into the saccharose fluid medium, and from this, as a starting point, 

 he would proceed to identify the organism. The primary plate 

 method is much more satisfactory than fluid cultures, because 

 foreign organisms, in some cases, appear to hinder the develop- 

 ment of Bac. levaniformaiis. 



So far as the economic importance is concerned, it is, perhaps, 

 .impossible to estimate the loss entailed directly or indirectl}^ 

 through the activity of the organism. In many cases raw sugar 

 has been known to have deteriorated during storage at the mill, 

 in transit to and in storage at the refinery. At one refinery in 

 Sydney the loss through inversion during the storage of the raw 

 sugar has at times been considerable. During the last three 

 3^ears, however, the Colonial Sugar Refining Company, suspecting 

 the loss to have been due to the activity of micro-organisms, have 

 altered their methods of manufacture, and the sugar is now less 

 subject to change. In three years the average loss through 

 deterioration has been reduced from 0-5 % to 0-1 % on the whole 

 stocks. This means that the loss of pure sugar on an annual 

 stock of say 50,000 tons, which three years ago was 250 tons, 



