What is bactofugation?

Bactofugation is a process used to eliminate bacteria contained in milk using centrifugal force. It is a special form of separation of microorganisms, mainly spore formers (Bacilli/Clostridia) to enable milk to be sterilized at lower temperature-time combinations. In order to be more effective, hot milk is used because it shows lower resistance to the destruction of bacterial cells compared to the cold.

Bactofugation is used to improve the bacterial quality of raw milk and also used to enhance the quality of powders, consumption milk and cream. This mechanical process is mainly used in the production of cheese to eliminate anaerobic spores that can affect the flavor and destroy the texture of cheese due to uncontrolled gas formation.

Bacteria removing centrifuges or bactofuges support a wide variety of dairy processes. Applications range from single-stage bacterial clarification through the 2-stage process to the special bacterial clarification of drinking milk, and variable bacterial clarification of cheese milk, treatment of whey concentrate and pre-treatment of milk powder.

The objectives of bactofugation are as follows:
· To improve hygienic quality of milk
· To avoid heat resistant bacteria without resorting to excessive heating
· To ensure exceptionally high degree of bacteriological purity in milk.

Bactofugation uses a centrifugal force to remove bacteria and spores from milk as a simple and cost-effective complement to regular pasteurization. Bactofuge are special nozzle clarifying separator with high separation precision that can remove microorganisms from milk based on their density difference (skim milk – 1.036; bacteria – 1.07 – 1.13 g/cm3).

During the process, centrifugation force is gradually accelerated to achieve gentle treatment. The optimum bactofugation temperature at which the best results are achieved is 55-60 °C. In the bactofuge, the milk containing bacteria and spores is pushed outwards and collected outside the bactofuge. Bactofugation of milk can remove 80-90% bacteria and 90-95% of spores.

Bacterial clarification is recommended before processing into cheese, because this allows the addition of nitrate to prevent so-called blowing to be significantly reduced or even dispensed with.

There are two types of bactofuge:
· Two–phase bactofugation have two openings at the top of the drum, one for continuous drainage of bactofugated milk and one for the bactofuge (2–3 % of the total amount of milk).
· The one-phase Bactofuge has only one outlet at the top of the bowl for the bacteria-reduced milk. The bactofugate is collected in a sludgespace at the periphery of the bowl and discharged at preset intervals.
What is bactofugation?