Your Milk needs to be produced as hygienically as possible. Bacterial contamination is the most important cause of hygiene-related problems as milk is an excellent source of food for bacteria. When milk is at a temperature of about 35oC bacterial numbers can double within half an hour- so, within two hours, 1,000 bacteria in a mL of milk can become 10,000 bacteria and, within 5 hours, 1,000,000. Temperature is key, below 5oC most bacteria which affect milk quality do not multiply. However, the bacteria are not killed they are just dormant waiting for an increase in temperature to start reproducing again. High levels of bacteria in milk affect both its manufacturing properties and its shelf life. Measuring the number of bacteria in milk is thus an extremely valuable measure of quality.
The problem is preserving the quality of raw cow milk and its complying with the main standards for dairy buyers. The initial quality of milk is found to be preserved when it is intensely cooled only during the first stage of its production.
Milk produced under hygienic conditions will retain good quality for a period of up to 15 to 20 hours. However, it is not only the storage temperature that is important; the cooling time to reach storage temperature, normally 4 °C, is also critical. Bulk milk coolers have been specially designed to cool the milk to 4 °C within a specified time period
Rapid cooling to below 4 °C greatly contributes to the quality of the milk on the farm. This treatment slows down the growth of the bacteria in the milk, thereby greatly improving its keeping qualities
Bulk milk coolers, generally, are designed to cool the milk to 4°C within a specified time period, normally 30 minutes.
However, it is vital to recognise that cooling is a part, not a solution, for hygienic working conditions. Avoiding infections through good hygiene practices, and cooling the milk as soon as possible after milking, combine to ensure high milk quality
Cooling is the part of the solution against growth, and with efficient cooling and good hygiene practice is the solution to reduce micro-organisms.
If pre-cooling and refrigeration do not quickly and effectively get the temperature of the milk below 7oC, the bacteria that are naturally present in the milk at low numbers will multiply leading to elevated Bactoscan.
High thermoduric count
Thermoduric are bacteria which can tolerate high temperatures. The most common cause of a high thermoduric count is inadequate cleaning of the milking plant. There is often hard milk residue on the upper surface of the milk lines and visible residue in the tanks. Less commonly, thermoduric can arise because of environmental contamination
A recent visit to a farm it was noted the farmer was under the impression that the milk cooled in 20 minutes , however with a temperature recorder it took over one hour .
Do you know how long it takes to cool your raw milk?