Control thermoduric bacteria
A recent Teagasc Dairy Newsletter article focused on thermoduric bacteria, which survive pasteurisation and can affect milk quality, and can be controlled through proper cow hygiene, milking practices, and effective cleaning of milking equipment.
Thermoduric bacteria naturally occur in the cow’s environment in soil, faeces, animal feed and bedding. These bacteria survive the pasteurisation process, and therefore cause issues in relation to milk processing and can limit the shelf life of pasteurised milk. Increased emphasis should be placed on the correct management practices in order to control thermoduric levels.
Cow cleanliness
Initial contamination of milk occurs during the milking process if udders or teats are contaminated with material such as soil or faeces. This often results in moderate thermoduric counts. Ensure the cow’s environment is kept clean, with particular focus on farm roadways and collecting yards. Clipping cow tails and udder hair will help improve cow hygiene. Milkers should always wear gloves when milking and wash them regularly throughout the milking process.
Correct plant cleaning procedure
Following a recommended plant cleaning procedure is critical to the prevention of an environment that will facilitate milk contamination. Where thermoduric counts are very high, milking plant contamination is the likely the cause.
Remember the three Ts with regard to plant cleaning
Temperature
Ensure sufficient hot water is available for washing (75-80oC) – hot wash solution should still be at least 45oC at dumping for effective cleaning.
Titration
Ensure detergents are used at the correct concentrations – a higher concentration (1%) will be required for cold washing, and where automatic washing systems are fitted, regularly check that the correct volume of detergent is being used, and always recalibrate if changing products – where peracetic acid is being added to the final rinse ensure all detergent has been rinsed from the plant before circulating the peracetic acid solution.
Turbulence
The ‘sloshing effect’ of the wash solution moving through the plant is an important part of the washing process. Check that all units are washing correctly – a small issue like a blocked air bleed on a cluster is enough to affect this. Ensure there is always a small amount of solution in the wash trough when the wash solution is circulating. Finally where an air purge system is fitted, listen to check that it is functioning properly, as it is a vital part of the wash process in larger parlours.