16 SCIENCE BULLETIN, No. 20. 



The system of working and salting butter on an open worker facilitates 

 the inclusion of many bacteria, moulds, oidium, and yeasts. 



The plates, poured with the waters used at the factory, suggests that 

 bacteria are reduced in numbers by chilling to 40 deg. Fah. The atmospheric 

 exposure plates indicate plainly the amount of re-contamination that took 

 place from exposure of the cream and butter to the conditions and surround- 

 ings of these old and (in a hygienic sense) badly constructed rooms. They 

 also point to the advisability of doing away with all overhead obstructions 

 (beams, pipes, belting, flat ceilings, &c.) that collect or distribute dust. 



The presence of such large numbers of undesirable water bacteria as those 

 shown in the plate exposed over the cream-receiving vat (adjacent to the 

 water-spray tower), and in subsequent plates of cream and butter, indicates 

 the danger incurred in exposing cream and butter to outside influences in 

 this case arising from the infection constantly being carried into the factory 

 by the spray of the condenser water tower, the source of supply for which 

 came from the stagnant lagoons described above, The necessity of draining 

 all such stagnant pools and lagoons cannot be too strongly emphasised. 



Example 2. 



It had been noted that the choicest quality butter manufactured in a 

 certain large factory, while true to description as regards quality 

 immediately after manufacture, soon began to show signs of deterioration, 

 and when kept in cold storage for any lengthy period became unmistakably 

 "off" in flavour and aroma. 



As a result of the series of examinations made at different stages of the 

 manufacture, it was ascertained that while the pasteurising of the cream was 

 effectively done, in that the bacteria were practically all killed, yet this same 

 pasteurised cream, on being put into the churn, was found to be contami- 

 nated in the same manner as when first received at the factory. On inquiry 

 it was found that the manager, following out advice he had received, was 

 using a quantity of high acid unpasteurised cream as a '* starter " for that 

 which had been neutralised and pasteurised. The " starter " cream was 

 found to contain similar germs to those in the bulk of the supply, and as a 

 consequence the work and expense of pasteurising were being nullified. On 

 the plates being shown and the matter explained, the factory manager at 

 once discontinued the practice. 



Selecting special cans of cream from the general supply to be used as 

 "starters" in this way is a very dangerous procedure; even with the most 

 skilled operator mistakes must occur, and it should be discontinued wherever 

 it has been in vogue. In propagating and using " starters " there is no room 

 for guess-work. 



This factory, as in the previous example, is an old one erected some twenty 

 years ago, but in a better state of repair and kept in a much more sanitary 

 condition. The design is similar, and likewise there are a number of rooms 

 on the first storey. The main walls and partitions, as also the ceilings and 



