12 



Dairy Bacteriology. 



Food. The bacteria like all other plants must have 

 their food in solution. Where they apparently live on 

 solids, such as meats, fruits, etc., they dissolve the food 

 substances before utilizing the same. If the solutions 

 are highly concentrated, as in the case of syrups, pre- 

 serves and condensed milk, the bacteria cannot readily 

 grow, although all of the necessary food ingredients 



FIG. 3. PHOTOMICROGRAPH OF LACTIC ACID BACTERIA. 

 Each cell is an individual organism, magnified 1250 diameters. 



are present. When such concentrated solutions are di- 

 luted, bacterial growth will take place and the solutions 

 will spoil. 



Generally speaking the bacteria grow best in a neutral 

 or slightly alkaline solution rather than in acid liquids. 



Temperature. One of the most important condi- 

 tions influencing the rate of growth of bacteria is the 

 temperature. Each form has a minimum temperature 



