The “Smear” of Brick Cheese and its Relation to Flavor Development

Abstract

The heavy growth of microorganisms on the surfaces of Brick cheese during the early stages of ripening is called the "smear." This smear appears only with proper conditions of temp. and humidity. Yeast-like organisms develop first in large numbers and are succeeded by micrococci and rod-shaped organisms of the Bacterium linens type. The smear reduces the acidity of the surface layer of the cheese while it is growing luxuriantly. The surface sections of Brick cheese show no marked changes in water- and alcohol-soluble N-containing compounds that are not also apparent simultaneously in the inner sections. There is no measurable evidence of ripening "from the outside" although the gradual diffusion of the characteristic surface flavor is very obvious. It seems probable that the slight odor of extensive protein decomposition which distinguishes the flavor of normal Brick cheese is produced by the microorganisms growing on the surface of the cheese and that the characteristic odor itself is absorbed by the cheese. The expts. suggest that the flavor of Brick cheese, and related smear-ripened types, may be controlled by regulating the development, activity and preservation of the smear.