SCIENCE BULLETIN, No. 20. 



0*6 per cent, of lactic acid. The plates showed the presence of a total of 

 162,749,000 micro-organisms; of these, 1,840,000 were organisms of the 

 Bact. Coli group, or undesirable lactose fermenters, of which three varieties 

 were isolated, viz., Bact. Goli communis, Bad. acidi lactici and Bact. lactis 

 cerojenis. Their presence in creanoi is evidence also of a proportion of volatile 

 acids (acetic and formic), so the 160,250,000 true lactose fermenters, Bact. 

 lactis acidi type, were not entirely responsible for the acidity of the cream. 

 Amongst the 770,000 gelatin liquefiers and casein digesters, were Bact. 

 prodigious, a species of the Proteus group, and Sarcina lutea, a liquefying 

 micrococcus and cladothrix sp. ; 19,000 micro-organisms, comprising species 

 of moulds, oidium and yeasts, were counted, while the 50,000 bacteria 

 causing alkalinity or no apparent change in litmus milk were both bacillary 

 and coccal forms. 



Sample J\ Cream, after Pasteurising. The cream was collected by means 

 of a sterile pipette immediately after being discharged from the outlet pipe 

 of the pasteuriser at a temperature of 180 deg. Fah. The sample was 

 neutralised to 0'2 per cent acidity with lime, and pasteurised by means of the 

 flash system, then cooled to 54 deg. Fah. by passing over pipe-coolers. 



It has been seen from the figures in Table I that 162,749,000 micro- 

 organisms in 1 c.c. of the cream were reduced by pasteurisation to 24,700. 

 Of these there were 200 per c.c. gelatin liquefiers of the B. Mycoides type of 

 spore-forming organisms. The remainder, 24,50.0 per c c., were insignificant, 

 inasmuch as only slight acidity, without noticeable taste or odour, was 

 produced by them in litmus milk in three weeks. 



Sample K\ Cream immediately prior to Churning. After being pas- 

 teurised and pumped over the pipe-cojlers the cream was gravitated into 

 circular holding vats, each about 6 feet in diameter and 4| feet deep, provided 

 with semi-rotary pipe brine coolers. These vats were placed in a room about 

 12 feet wide by some 40 feet in length. The walls, which were of nbro-cement, 

 were cracked, and broken, and dirty. The floor, also greasy and dirty, was 

 of hardwood, badly jointed, and in places leaked through to the basement 

 underneath. The beading round the bottom of the walls was loose and 

 rotting, and the room was ill-ventilated and lighted, and generally in a state 

 of disrepair and uncleanliness. The vats had open tops and the contents 

 were exposed to contamination from the above conditions. No " starter " 

 was added to the cream, which, pending churning, was held over-night 

 (twenty hours) at 57 deg. Fah. Here the plates show that 1 c c. of cream 

 contained 1,291,500 micro-organisms; 180,000 of these were found to be 

 desirable lactose fermenters or organisms of Bact. lactis acidi type and 

 1,000 were acid and gas formers of the coliform group, viz., Bact. lactis 

 oeroyenes. Amongst the 543,500 gelatin liquefiers and casein digesters were 

 Bact. proteus mirabilis, Ba^t. fluorescens liquejaciens, Sarcina lutea, and a 

 gram-positive bacterium. The 367,000 producing alkalinity or no change 

 in litmus milk were both rod-shaped and spherical forms, some being 



