PDF Library

Please click on the downloadable PDF files to open them.

Technical Advice

Somatic Cell Count
The Somatic Cell Count normally rises as a result of Mastitis in the udder. Mastitis is caused by a bacterial infection and resulting inflammation of the udder. The management of somatic cell counts is therefore heavily reliant on the management of mastitis in the herd and in individual cows within the herd..


Milk Testing
Every dairy company carries out a series of milk quality tests on all milk supplied.
The following notes give background on these tests.


Total bacteria come mainly from the milking machine itself and usually mean that the milking machine is dirty. However, the total bacteria downgrade can also be caused by other problems such as water quality and a type of mastitis.


Coliform Grades
Coliform bacteria are usually found in dung and soil and sometimes in the water supply. However, coliform grades are usually the result of poor milking machine cleaning. Coliform bacteria are easily killed by hot water. Once coliform bacteria are in the plant they will grow rapidly if the milking system is not clean. Hygienic milking and cleaning procedures are required to prevent and control coliform bacteria.


Inhibitory Substances
The inhibitory substance test is carried out to detect substances that inhibit or reduce the growth of bacteria in milk. The test is performed by adding a standard bacterium to a milk sample. The presence of an inhibitory substance will stop the bacteria growing. This is indicated by a lack of colour change to a standard indicator dye.


Sediment is objectionable to the consumer and can reduce the efficiency of the manufacturing process.


Chemical Flavours
The flavour of some chemicals may be barely noticeable in the supplier’s consignment and even under laboratory assessment, but when certain products are manufactured then problems occur.


Foaming and Churning
Foaming and churning of milk can cause serious quality defects. Milk contains an enzyme, lipase, which will under certain conditions split milk fat into glycerol and free fatty acids.


Freezing Point Grade
Excess water in milk causes freezing point grades. Water can enter milk in a number of ways. For example, water leaking into the milk side of the cooler, not draining the plant after putting a wash through, and machine failure or permanent (illegal) reverse flow connections. Rinse water going into the milk tank is the most likely cause.


Plants That Taint Milk
Milk can be tainted by certain crop plants and some pasture weeds. Often the substances that cause the taints are fat soluble and become concentrated in high fat products such as cream and butter. The taints are sometimes difficult to detect in the milk tank but show up later in the product.


Thermodurics are a heat resistant bacteria. Even a small number may have a large impact on shelf life.