6o 
HOUSEHOLD BACTERIOLOGY 
Bacteria 
Necessary 
for Flavor 
in ptomaine poisoning. This would be putrid cheese. 
As with cream, so the cheese curd may be inoculated 
with the particular germ which, by its growth and life 
processes, is known to give the desired flavor, just as 
a person may be inoculated with a certain disease germ. 
In both the processes are similar, although the results 
are different. 
If cheese be made from boiled or Pasteurized milk 
or from that to which a germicide has been added, the 
ripening process does not go on, showing that the 
living micro-organism is necessary to the production 
of the desired flavors. 
Pure cultures are now used for cheese ripening and 
therefore cheeses that have heretofore been imported, 
because the species of bacterium necessary was not 
native to this country, may now be made here when the 
conditions of growth are understood. 
Butter and cheese are possibly the most common 
foods whose desirable and varied flavors are due to 
bacteria and molds, but there are others where their 
work is often productive of a pleasant taste. 
VINEGAR 
Anyone who has seen a cider mill in operation in 
the country or has seen the cider made “while you 
wait” at a city fair knows the process by which the 
whole apple is crushed and the juice extracted. Such 
juice must, of course, be seeded with wild yeasts and 
with bacteria which were on the skin of the fruit or 
in the air. When it runs directly from the press, it 
