Sweet Flavor in Cheddar Cheese.
A new cause
of cheese
faults.
By methods similar to those just given the cause of the common and costly cheese fault known as “sweet flavor” has probably been found. This investigation was demanded by the occurrence in some of the best-conducted factories of outbreaks of the trouble which most thorough cleansing and scalding fail to overcome. It is believed that these attacks result in annual loss to the State of at least $10,000. The trouble is of obscure origin and is peculiar in its development, manifesting itself in flavors of varying intensity and character, from a faint sweetness to a well-marked fruity smell and taste, and seeming to appear and disappear without rule or method. This made study more difficult than in the case of well-defined troubles; but its manner of development in the cheese indicated some living germ as the cause; so the attempt at solution of the problem was made from that standpoint.
By cultural methods, study was made of the flora of good and poor cheeses; that is, the various forms of plant life existing in these cheeses were separated from each other and their forms, actions and effects noted. These forms of life were mostly bacteria and yeasts; and, contrary to the usual rule, it was the latter which finally seemed to demand attention.
Yeasts are plants a little higher in the scale of life than bacteria, a little larger but still microscopic, and differing from bacteria in their mode of reproduction, which is by budding of a new cell from an old one rather than by division of an old cell into two new ones of equal size. Their most characteristic action is the formation of alcohol and carbon dioxide; which makes them indispensable in brewing and bread making.
In good cheeses almost no yeasts were found, but in the sweet-flavored cheeses sometimes half of the germs present were yeasts; and they were always found where the sweet flavor was noticed. Yeasts have not been recognized, hitherto, as a cause for such cheese faults; but their presence in such numbers cast strong suspicion upon them; which actual work proved to be well founded, for pronounced cases of sweet flavor developed in cheeses made from pure milk inoculated with the yeasts; and the vat in which the cheese was made became contaminated so that, without further intentional inoculation, sweet-flavored cheese was produced where none had been known before. As yeasts have hitherto played minor parts in dairy investigations, no classification of those found has yet been made, nor has the exact flavor due to each one been determined. Further study is being given to the subject.