CREAM CANS

Wairarapa Times-Age, 22 August 1938, Page 3

CREAM CANS

SOURCE OF CONTAMINATION CHECKING BACTERIAL ACTIVITY. One of the most common sources of the contamination of cream, and one that is often overlooked, is the badlywashed can. More cream is spoilt by being stored or carried in a badly washed can than by most other ways. This applies to cans in good order as well as those that are dented and rusty. The reason is not far to seek. Hundreds of cans pass through the same rinsing water of the mechanical can-washer at the butter factory daily, and although a final steaming is carried out in the last stage of the washing process, it is not of sufficient duration (nor is it practicable) to sterilise thoroughly all of the cans thus treated, states the “Australasian.”

It should be obvious that cans which have contained second-grade cream will require extra attention, in order to prevent the transmission of taints due to bacterial activity—such as cheesiness and rancidity—to the fresh supplies of cream. A tallowy smell which is often found in returned cans may be due to inefficient washing, followed by exposure to the heat of the sun, causing deterioration of the fat.

It is, therefore, advisable in order to safeguard the quality of cream, to rinse all cans on their return from the butter factory with boiling water to which a little washing soda has been added. The cans should then be rinsed with clean boiling water to remove all traces of the soda.

The storage of the cleansed cans is important. They should be placed upside down on a suitable rack to allow for cooling and drying. On no account should anything but boiling water be used for the final rinsing, nor should any attempt be made to dry the cans with a cloth. The storage rack should be placed in such a position as" to be well removed from any possibility of contamination from the stockyard. Although the term pasteurisation is very commonly used nowadays, there perhaps are many who do not know its origin and meaning. Actually it dates back to 1860-1864, when Louis Pasteur, the famous French scientist, conducted experiments on “diseases” in wine and beer, and found that heating for a short period at a temperature of 140 deg. F. was sufficient to present abnormal fermentations and the souring of these beverages. The process of heating liquids to check the growth of undesirable microbes was extended to other industries, and was given the name pasteurisation in honour of Pasteur, who had first employed .it. . * .

Today it is best known through its application to the dairying industry. The pasteurisation of milk simply means that the milk is heated to a temperature of 145 deg. F. for 30 minutes, and then cooled as quickly as possible to 50deg. F. or lower. Cream in the butter factories is heated to 185 deg. F. for a few seconds, and then cooled rapidly to 40deg. F. Pasteurisation aims, firstly, at making milk and milk products safe, by destroying any disease germs that may be present; and, secondly, at improving the keeping quality of butter and cheese made from milk and cream so treated. It, however, has its limitations. It cannot perform miracles, such as improving the grade of cream from second to choice, or eliminating strong taints. Most dairy farmers are now aware of this, and know that the production of choice quality cream depends on the care and attention given at the farm, and that the pasteurisation process is beneficial in that a butter of choice quality can be manufactured to withstand long periods of cold storage.