C. P. Cox

606. A variability study in firmness in cheese using the ball-compressor test

A variability study of ball-compressor readings on the upper faces of 10 Cheddar cheeses has shown that: 1. Percentage elasticity readings were generally less discriminating than total deformation readings. 2. As measured by the total deformation, there were firmness gradients across the faces of the cheeses, which tended to increase in firmness from the centre outwards. Further experimentation to determine consistent firmness differences on cheeses has been recommended and meanwhile, from preliminary examination of firmness discrimination, it is suggested that four total deformation readings may give sufficient accuracy for many routine purposes.

Relations between composition and viscosity of cow's milk

Theoretical and practical aspects of the apparent or effective viscosity of milk have been studied by many workers: see reviews by Scott Blair(1,2,3). Seidler & Elke(4), Cox(5), and others have considered the relations between observation temperature and viscosity measurements; Mohr & Oldenburg(6) and Puri & Gupta(7), for example, have investigated the effects of differences between individual viscometers. Other workers, including Puri & Gupta(7), Kobler(8) and Spottel & Gneist(9), have examined the viscosity of whole raw milk after different times and temperatures of storage; and Weinlig(10), Trout & Weinstein(11) and Whitnah, Rutz & Fryer(12,13) have studied changes in viscosity values in connexion with various processes such as pasteurization and homogenization.

493. Concerning the interpretation of observations, obtained from records and experiments, on milking dairy cows

1. Some questions concerning the interpretation of observations on milking dairy cattle are considered. 2. A formula is presented for analysing the contributions of changes in the numerator and denominator to the changes in a percentage or fraction, and the formula is applied to changes in the composition of milk. 3. The depressions of the butterfat and solids-not-fat percentages consequent on diets reduced in hay in a dairy-cattle feeding experiment are examined with this constituent analysis. The contributions of changes in the magnitudes of the aqueous, butterfat and solids-not-fat constituents to the difference between the butterfat percentages of cows on two treatments, 18 lb. hay/day (control) and 6 lb. hay /day, are about equal. There is an apparent qualitative difference between the effects of the two non-control treatments, and a reduced yield of butterfat would alone largely account for the lower butterfat percentage of cows on the 2 lb. hay /day treatment.