FOODS — HUMAN NUTRITION. 355 



These experiments do not support the belief that the moisture of the crumb 

 is imparted to the crust, causing it to lose its crispness. The analytical data 

 show conclusively that the loss of moisture by the crumb is practically always 

 accompanied by a corresjtonding loss of moisture by the crust. In the case of 

 ordinary breads, lactic acid acidity does not develop within six days of baking, 

 either in the unwrapped or in the wrapped loaves. 



" The use of semiporous and paraffin wrappers does not injure the quality of 

 the loaf after the third day. Up to that time the keeping quality both as to 

 condition of crumb, flavor, and odor is enhanced by the use of the wrappers. 

 Unwrapped bread loses its freshness after the first day. But little difference 

 is observed in the condition of the straight dough pan bread, straight dough 

 rye, sjionge dough rj-e bread, and straight dough Vienna hearth bread. Bo- 

 hemian rye sponge dough wrapped or unwrapped bread is not of satisfactory 

 quality on and after the third day." 



This paper was followed by a discussion. 



A report of a chemical and bacteriological study of wrapped bread, B. R. 

 Jacobs, J. A. Leclerc, and Maud L. Mason (Amcr. Jour. Pub. Health, 4 (1914), 

 No. 9, pp. 721-732). — In this investigation the following aspects of the question 

 of wrapi:)ed bread were studied : The kind of paper best adapted to wrapping 

 bread; the lapse of time after baking before bread should be wrapped to secure 

 the best results; bacteriological examination of both wrapped and unwrapped 

 bread ; and the relative weights of wrapped and unwrapped bread. 



The experimental procedure as carried out in the bakeries was as follows : 

 The rate of cooling of the freshly baked loaves was determined by means of 

 thermometers inserted in them immediately after removal from the oven. One 

 loaf from each baking was wrapped in sterile paper and taken at once to the 

 laboratory for bacteriological examination. At intervals of one hour for five 

 hours, three of the remaining loaves in each experimental baking were weighed, 

 wrapped, and set aside for examination. Some of the loaves were also allowed 

 to remain unwrapped in the bakery. On the next day both the wrapped and 

 unwrapped bread was taken to the laboratory by one of the regular delivery 

 wagons of the bakery and allowed to remain at room temperature. Some loaves 

 were exposed to the air and others kept in a closed show case, weights and 

 samples being taken at intervals. 



Bread wrapped in unwaxed paper lost more moisture than that in waxed 

 paper, and bread in paper waxed on both sides lost less moisture than that 

 wrapped in paper waxed on only one side. The firmness of the crust of all 

 the bread was directly proportional to the loss of moisture. It is therefore 

 probable that breads whose crusts are to be kept firm and dry, such as Vienna 

 and French breads, may be kept in the best condition by wrapping in porous 

 rather than in waxed paper. In the case of ordinary bread none of the papers 

 used showed any detrimental results and no objectionable features developed, 

 so far as could be determined by odor or taste, in wrapped bread even at the 

 end of 114 days. 



In the bacteriological examination samples were taken from the outside of 

 the loaf only. The results of this examination showed that the crust of the 

 loaf as it leaves the oven is practically sterile. If exposed unwrapped in the 

 bakery it may collect a large number of bacteria, but in 0.1 gm. samples of such 

 bread examined no organisms of the Bacterium coli type were found. Bread 

 which has been cooled for only one hour before being wrapped retained sufficient 

 heat and moisture to favor the growth of organisms, especially when waxed 

 paper was used for wrapping. The lapse of time before which bread should be 

 wrapped can be fixed approximately at three hours, since the bread reaches the 

 80967"— No. 4—15 5 



