CHAPTER VI 

 THE BREAD MOLD 



78. Molds. — We know that bread, if allowed to stand for 

 a time, becomes moldy. Spots, at first small and white or 

 gray, appear upon its strrface. Many of these spots are 

 covered with a fluffy substance. Under a hand lens, the 

 fluffy substance is found to be made up of many white or 

 grayish branching threads. The spots grow rather rapidly, 

 and in time they may cover the whole surface of the bread ; 

 their color changes to black, pink, red, blue, or green, and they 

 take on a powdery rather than a fluffy appearance. The 

 bread now has a characteristic " moldy " smell, and it grad- 

 ually loses its firm consistency, changing to a slimy mass. 

 Some of the changes in the bread are due to the action of 

 bacteria, which may be present in immense numbers ; but 

 the fluffy spots consist of fungi of various kinds that are 

 commonly called molds; they are much larger and more 

 highly developed than the bacteria and yeasts, and they 

 live upon the bread, using it as food. Similar mold spots 

 appear on exposed surfaces of cake, fruits, preserves, damp 

 leather, or in fact of almost any moist organic substance. 



One of the commonest of the molds is Rhizopus nigricans, 

 often called the bread mold, because it occurs so commonly on 

 bread, although it appears also on many other substances and 

 is said to cause a rot of sweet potatoes and of strawberries. 

 The fluffy mass that we first see on the bread is the body of the 

 fungus, and the powdery appearance as it grows older is caused 

 by the presence of its very numerous spores. The older 

 spots produced on the bread by this mold are black. 



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