A study has been made of the quality properties of 12 home-grown varieties of black-currant. Samples were obtained from six localities over a period of three years. The properties studied consisted of the aroma number, the organoleptic evaluation, and the degree of ripeness. As regards aroma number, great variations were noted between the samples. The influence of variety was rather slight. In general, the aroma numbers were higher when the summer was cool and the growing locality more to the north, probably by reason of the losses of volatile reducing substances at higher temperatures. The utility of the aroma number in characterization of quality seems limited in scope. Smell and taste were taken as the main criteria in the organoleptic evaluation. The differences between the varieties were not very great, but in any event a relatively consistent sequence was discovered. Consideration is given to some factors which influence organoleptic properties. The degree of ripeness of the samples, and the effect of this factor on the quality properties, were studied. The degree of ripeness displays a correlation with the corresponding effective temperature totals. Here, the effect of the ripeness factor on the results was only slight, as unripe berries were removed from the samples before analysis. However, some effect may have remained, to some degree influencing the colour strength, but the organoleptic properties to a lesser degree.

The Marvin A. Norcross papers relate to food safety and food residues, including integrating the concept of risk assessment into food production and processing. There are manuscripts for talks (including slides), publication, and awards. There is also all the research data associated with his Ph.D. titled "An Immunological Study of the Localization of Certain Chemical Carcinogens in Rat Tissue" and includes black and white photographs of dissections, camera slides, and microscope slides.