364. Studies on the bacteriological flora and keeping quality of pasteurized liquid cream

Abstract

1. The special conditions of the cream trade are discussed. Keeping quality is a major consideration which influences all operations and it has been shown that unusually high bacteriological standards of handling are essential.2. The requirements for bacteriological control testing are indicated, together with the limitations of existing standard methods.3. A rough sorting test has been developed which permits sufficiently rapid estimation of the probable keeping quality of heat-treated cream and which is applicable to routine grading of numbers of individual units.4. Data from 2558 samples of heat-treated cream are presented to show the relationship between the colony count, conform test, grading test, and keeping quality.5. Possible sources of bacteriological contamination have been indicated by the examination of 2337 plant samples. Commercial processing methods are discussed and satisfactory practical methods of operation have been developed to ensure a minimal bacterial population.6. The keeping quality of cream has also been studied in relation to the effects of cold storage before distribution and of exposure to atmospheric temperature during distribution.