510 EXPERIMENT STATION RECORD. [Vol.37 



inoculated in duplicate and a triplicate portion retained as a control. Only 

 10 per cent of the inoculated samples showed a greater deterioration than the 

 controls. The results indicate that " the original infection of the majority of 

 these samples was sufficient to cause their deterioration when suitable condi- 

 tions for this action obtained." 



Experiments conducted to determine the relative rate of deterioration of 

 sugar with varying amounts of absorbed moisture showed that deterioration 

 occurred only in samples having a factor liigher than 0.25. 



In a study to determine the relations between the rate of deterioration and 

 the density of the films of molasses surrounding the sugar crystals a series 

 of sugars was used which had factors of safety varying from 0.136 to 0.677, 

 with mola.sses films varying in density from 69 to 79° Brix. The samples were 

 stored for three months and a percentage deterioration was noted of 0.7 on a 

 sugar with a factor of 0.077, 0.6 on a sugar with a factor of 0.369, and 1.42 

 with a sample having a factor of 0.472. The small deterioration on the sugar 

 with the factor 0.677, which would ordinarily be considered very unsafe, is 

 indicated as being probably due to the lacli of certain impurities usually present 

 in plantation granulated sugar. 



Experiments on the influence of cold storage on the keeping of sugars sug- 

 gested the possible cold-storage warehousing of white sugar. In a further 

 study of the species of microorganisms causing the deterioration of sugar, the 

 18 bacterial cultures previously i.^Jdlated showed a great variation in deterior- 

 ative power, some cultures having as much as four times the deteriorative 

 power of others. Only two of the 20 yeast cultures isolated showed any in- 

 verting power, and this was very slight when compared to the action of the 

 bacterial species. " Mixed inoculations of torula and bacteria invariably re- 

 sulted in a deterioration greater than that produced by tlie torula, and much 

 less than where pure cultures of bacteria were introduced alone. No symbiotic 

 relation.ship between the two is therefore indicated in the results of these 

 experiments. 



"The maximum limit of density of the bacterial cultures was found to be 

 between 00 and 72° Brix, while no limit has yet been found for the activity of 

 the torula in fermenting invert sugar. Above 65° Brix the action of the torula 

 upon sugar solutions containing both sucrose and invert sugar is exclusively 

 confined to the latter, thus explaining the decrease in invert sugar during the 

 storage of sugars with low factors of safety. The bacterial species associated 

 with the deterioration of sugars have a very low minimum nutrient require- 

 ment. Standard gi'anulatetl sugar and distilled water in a 35 per cent solution 

 showed a loss of sucrose 2.09 per cent when inoculatetl with cultures of de- 

 teriorative bacteria. IMnntation granulated sugar showed a loss of 2.9 per 

 cent under the same condition. The addition of 1 cc. of a 1:1,000 molasses 

 solution to 100 cc. of the standard granulated sugar solution gave a deterie- 

 ration of 2.8 per cent, while the same addition to the plantation granulated 

 resulted in a deterioration of 4.9 i^er cent. The addition of 1 cc. of a 1 : 1,000 

 dirt suspension caused a deterioration of plantation granulated of 8.3 per cent. 

 These exi)eriments emphasize the importance of cleanliness in the manufacture 

 of white sugar of lieeping qualities." 



Experiments to determine acquisition of deteriorative power by the same 

 species of bacteria as those found in sugar, but isolated from other products, 

 showed in one case an increase in deteriorative power of about 1,100 per cent 

 when grown for successive generations in sugar solution. "This would indicate 

 that the most active infection of sugar comes from old sources of contamination 

 in the house, rather than from the dirt immediately introduced into the juice 

 from the soil adhering to the cane." 



