The Relationship of the Amount of Tyramine and the Numbers of Streptococcus Faecalis to the Intensity of Flavor in American Cheddar Cheese

Abstract

Exptl. American Cheddar cheese made with commercial lactic starter from pasteurized milk developed small amts. of tyramine, 4 to 87 [gamma] per g., and flavor of mild to medium intensity in 5 months of curing. The combination of lactic and S. faecalis starters in cheese produced the largest amts. of tyramine, 333 to 1397 [gamma] per g., and flavor of medium to sharp intensity. S. faecalis starter alone in cheese produced tyramine and flavor between these 2 extremes. In commercial American Cheddar cheese made from raw and pasteurized milk, cured for varying periods, there was a direct semilogarithmic relationship between tyramine content (25 to 2330 [gamma] per g.) and intensity of flavor. Of the 25 cheese samples, 18 gave plate counts in the special medium of over 100,000 S. faecalis per g. with a high count of 159 million. The 5. faecalis bacteria produced the tyramine, although other bacteria may contribute. Tyramine was not the Cheddar-flavor compound, but served as a means of measuring bacterial activity that accentuated flavor production. The activity of bacteria producing tyramine did not account for all cheese flavor. The increase in titratable acidity was related directly to cheese flavor intensity, and this relationship, even though subject to considerable variation, was too close in individual samples to be accidental. In a general way, the increase in volatile fatty acids and water-soluble N was related to flavor intensity, but variations in individual samples prevented a definite correlation and also established that these changes were incidental to flavor development.