57^ MICROBIOLOGY OF FOODS 



formation. "Sweet silage" always contains an appreciable amount 

 of acid. 



According to Hunter and Bushnell of the Kansas Station* four 

 groups of organisms are responsible for the changes occurring in the 

 silo: (i) the acid group, (2) the colon group, (3) yeasts, and (4) miscel- 

 laneous. They found that the most important acid formers belong 

 to the bulgarian group. Recently the use of cultures of B. bulgaricus 

 grown in milk as starters for silage fermentations has been advocated 

 in farm journals. Whether this practice will prove successful and 

 desirable remains to be seen, but it would certainly appear to be a logical 

 procedure for the reason that the addition of lactic cultures to beet 

 cosette silage has proved successful. 



Probably a great deal of the gas formation in silage is due to mem- 

 bers of the colon group. 



Plant enzymes are of some importance in silage fermentation. 

 Some of the starch of corn or corn stalks is converted into "sugar by the 

 plant diastase and the presence of a plant invertase which acts upon the 

 cane sugar present has been demonstrated. However, it is believed that 

 no appreciable proportion of the rise in temperature in the silo is due to 

 these or other similar purely plant activities. It is held by most 

 investigators that the important changes are due rather to bacterial 

 activity. 



Recently the work of Graham of Kentucky and others has brought 

 to light in a startling manner the importance of Bacillus botulinus in 

 relation to forage poisoning from silage and hay or straw. Because of 

 the fact that hay or silage responsible for stock poisoning was usually 

 moldy it was assumed that the mold was the responsible agent. Silage 

 at the surface of the silo becomes moldy and alkaline in reaction and is 

 considered by many stock men as poisonous because of the mold. 



It has now been demonstrated, however, that the most common 

 death-producing organism in silage is very similar if not identical with 

 B. botulinus, Pearson as early as 1900 demonstrated the relation 

 between a sporadic outbreak of forage poisoning and the poisonous 

 quality of ensilage fed to the stock in question. Stonge and Buchanan 

 of Iowa obtained positive results under conditions similar to the above. 

 More recently Bush and Gridley of Illinois and Graham, Brueckner 

 and Pontius of Kentucky, have shown B. botulinus or an organism 



* Kansas Station Technical Bulletin 2 (1916). 



