PASTEURISATION OF MILK FOR CHEDDAR CHEESE-MAKING. 291 
after heating milk for thirty minutes at 140° to 145° F. the 
lactic acid bacteria are present in much greater proportion — 
to the remaining organisms than in the raw milk. There 
is no evidence apparently available to confirm this observa- 
tion for regenerative pasteurisation at 165 F. MacInnes 
and Randell’ state that 24,500 out of a total of 24,700 sur- 
vivors from: flash pasteurisation at 180° F. produced only 
‘slight acidity without noticeable taste or odour at the end 
of three weeks. 
In one case mould colonies were present in the cultures. 
‘These were probably a reinfection from a nearby curing 
room. Tom and Ayers?’ consider that the pasteurisation 
for thirty seconds at 165°—175° does practically destroy 
the spores of Aspergillus, Circinella, Mucor and Penicillium 
species experimented with by them. 
e 
Moruya Co-operative Cheese Company. 



| Micro-organisms other than Streptococcus lactis (Lister) present 
in milk at time renneting. 






Raw Milk. Pasteurised Milk. 
700,000 5000 
212,500 6000 
1,515,000 130,000 
* 252,000 
1,025,000 14,000 
863,125+ | 39,000+ 
* Petri dishes broken in transit. + Average of four. 
One of the beneficial influences of the pasteurisation 
process in cheese-making lies in the comparatively clear 
field left for desirable bacteria in the processed milk. These 
bacteria greatly predominate in the milk at the time of 
coagulation owing to the addition of starter to this cleared 
field. Once the coagulum has been formed it is of course 
almost impossible to introduce any new bacterial type, and 
