The Relation of Certain Plant Processes to Flavor Development in Market Milk

Abstract

Summary The relation between a number of plant processes and the quality of market milk as indicated by its flavor has been studied. In the absence of more suitable methods the flavor of the milk was determined organoleptically. One of the most important of the plant processes bearing upon the quality of market milk is the use of an effective grading system. Such a system should provide for bacterial, flavor, and temperature control in the raw milk up until the time of delivery. Pasteurization improves the flavor of most raw milk. Continued heating at 142°F. for over one hour, however, may result in a noticeable cooked flavor. Milk should not be brought into contact with either iron or copper surfaces. Benedict nickel also may have a detrimental effect upon milk flavor. The development of a tallowy flavor in milk is closely associated with metal contamination. Glass and Allegheny metal have practically no ill effects on milk flavor. Two kinds of flavor defects may occur in milk exposed to sunlight, one a tallowiness, and the other a burnt flavor. Diffuse light is an important factor in the development of tallowy flavor in milk, especially that containing an added copper salt. The use of chlorin sterilizers on farm and plant equipment should be confined to those of a non-corrosive. nature. In no case should the-disinfectant be added directly to the milk, and all utensils and equipment treated with chlorin sterilizers should be rinsed with uncontaminated water before adding the milk. Otherwise, puckery, unclean, or medicinal flavors may develop. The odor and flavor of phenol, when present in milk is greatly intensified by the presence of chlorin in the form of sodium hypochlorite.