Clean dairy, quality milk

Cleaning must be done properly as bacteria can build up in the plant and contaminate milk. The bacteria affect milk quality by breaking down the components in milk. This reduces the shelf life of milk and milk products and produces off flavours in cheeses and milk powders.

Machine cleaning maintains milk quality by aiming to removing milk residues from plant and destroying resident bacteria. 

Milk is a difficult material to clean from surfaces because it has many different components, each requiring different temperatures and chemical environments to aid removal.

Cleaning does not allow shortcuts, but good equipment and systems will minimise the time it takes. Adopting a cleaning routine tailored to a milking plant and other available resources (volume and quality of water) will reduce the need to manually scrub or ‘bomb’ clean a plant.

The benefits of ensuring you have the correct cleaning process include:

Maintain milk quality. Put in place a process which ensures cleaning is done properly, so that all residues are removed and bacteria are destroyed.

Ensure safety issues are considered.

Bacteria can enter the plant from cows (teat skin and infected udders) and the environment (drawn into the cluster). The milking environment is ideal for bacteria growth. Effective machine cleaning will control the presence of bacteria in a plant.

The quality of water used is important in achieving a successful clean. There are four key elements to a cleaning routine:

Thermal energy from hot water. 

Time taken for effective cleaning. This is often dependent on the type of cleaning system.

Kinetic energy from water turbulence: dictated by water volume and flow rate (hence the use of a flushing pulsator to improve the cleaning of milk lines and receivers).

Chemical energy from acid (pH 2.5-3.0) and alkali (pH 11.5-12.5) detergents.

PLANT CLEANING ROUTINES

AN EXAMPLE of an ideal cleaning sequence which includes the minimum requirements is as follows:

Cold water rinse

The post milking rinse needs to be completed immediately after milking or milk collection. It rinses most of the residual milk from the milking system and bulk milk tank.

Hot water alkaline / acid wash

The milking system should be hot washed as least once a day and twice a day during high risk periods (e.g. when grading, calving). The bulk milk tank should be hot washed after every collection. The purpose of the hot detergent wash is to remove any adhering non-rinsing milk residue. This process should alternate between acid and alkaline in some systematic way to ensure all residues are removed on a routine basis.

Alkaline detergent wash

A hot water alkaline wash should be done at least twice weekly on the milking system and bulk milk tank. The wash water should be recycled for 5-7 minutes once water discharging the plant/tank is hot.

Cold water acid wash

A cold water acid wash is normally carried out at night and hot alkaline washes done after the morning milking.

Acid sanitiser detergent wash

This should always be the final wash through the milking system and bulk milk tank. Acid sanitiser washes can be used hot or cold.