A relatively simple method is described for the manufacture of Cheddar cheese under controlled bacteriological conditions. This method is shown to give the required degree of asepsis and to permit the manufacture of cheeses of uniform and normal composition.

The composition, bacteriology and flavour of 28 ‘aseptic’ cheeses and of 18 ‘nonaseptic’ control cheeses made by this method are discussed. Thirty-nine of these cheeses were made using singly 3 strains of Streptococcus cremoris and 2 strains of Str. lactis as starter and 7 were made using gluconic acid lactone in place of starter. The effect of inoculating the milk with a strain (25·2) of ‘Lactobacillus plantarumcasei’ and a strain (L1) of micrococcus was also investigated.

The term stickiness, as used in the butter industry, refers to that property of butter which permits it to remain attached to solid surfaces. It is a phenomenon in which the components of force caused by adhesion and cohesion are inseparably involved and have been described by the term ‘hesion’. Hesion measurements of commercial samples of conventionally-made butter were much higher than those of continuously-made butter. The results of experiments on conventional and laboratory continuously-made butter from the same butterfat source indicated that the characteristic crystal structure influenced the hesion values. Homogenization of Gold'n Flow and conventional commercial butters markedly increased hesion readings. When nitrogen gas was added to pre-crystallized continuously-made butter the hesion values decreased with increasing gas content. However, there was an increase in the amount of butter which remained on the adherend when it became detached from the butter surface. Limited experiments on the effect of gas content in conventional butter also indicated that an increase in gas content resulted in a decrease in hesion values with more butter remaining on the adherend. The results of this investigation indicated that the crystal structure was responsible for the adhesive property of butter and the gas content influenced the cohesive property. It would appear, then, that both the crystal structure and the gas content play an important part in causing stickiness of butter.

The serological identity of group N streptococci was established by Shattock & Mattick (1943), who discovered that Streptococcus lactis and Str. cremoris had a common antigen, which differentiated them from the rest of the Lancefield groups of streptococci. Although phage typing of these organisms has met with some success (Nichols & Hoyle, 1949; Whitehead & Bush, 1957) attempts to type these organisms with rabbit antisera so far have failed (Briggs & Newland, 1953).

The effects of depriving cows of pasture, for part or all of a single interval between the morning and evening milkings, on milk yield and composition have been investigated. The yields of milk and solids-not-fat, but not of fat, were reduced. The characteristics of the butterfat obtained at the first 2 milkings following grazing restriction differed markedly from those of cows allowed to graze normally.

The changes observed suggested that the grazing restriction led to a temporary reduction in the supply of volatile fatty acids from the rumen and an increased utilization of fatty acids from body fat by the mammary gland.

A study of casein micelles was made with the electron microscope, using very thin sections cut from micelles embedded in Araldite. The micelles appear to be built up of units that are approximately spherical, about 100 Å in diameter and of about 300000 molecular weight.