Centrifuge
Dairy products can become heavily contaminated by bacteria and spores, somatic cells and non-milk constituents. This makes it all the more important to remove impurities from the raw and vat milk as well as the whey efficiently, a job that is reliably performed by the bacteria removal separators from GEA.
Optionally, the bacteria removal separators can be equipped with the GEA proplus system. With proplus it is possible to extend the ejection intervals during production up to six-fold compared to conventional bacteria removal separators. The result is a significant boost in protein yield from the raw milk used by means of consistent loss minimization of up to 75 %. In addition, there is a decrease in costs for waste water, maintenance and wear.
The bacteria removal separator separates in particular spore formers such as Bacillus cereus, heat-resistant up to 128 °C and cold-tolerant at the same time, which negatively impact the shelf life of the drinking milk due to sweet coagulation. A large number of cheese defects can likewise be prevented effectively through the application of bacteria removal separators.
The use of nitrate is also largely superfluous or can be dispensed with completely. Due to the higher specific gravity of the spores compared to the raw milk and skim milk, they can be removed from the milk extremely efficiently with the aid of bacteria-removing centrifuges. The design of the centrifuge – the feed, disk stack and centripetal pump in particular – is configured optimally for this task. Additionally, every GEA bacteria removal separator is equipped with a so-called recirculation system. Up to 3% of the feed volume is tapped off as carrier liquid and recycled back into the feed. In this way, the spores can be reduced by up to 99%.
In the clarifiers the raw milk is separated in to the heavy phase “sludge” and the light phase “clarified milk”. Directly after the light phase leaves the clarifier, a sample has to be taken in order to avoid any recontamination. The sample must be cooled to a temperature < 3 ˚C using iced water or dry ice. This temperature may not be exceeded until the samples are examined after no more than 24 hours. For detailed information about the sample taking procedure please contact us.
Evidence of | Used in (product) | Damage caused | Name of method | Reference method |
Total bacteria count | Fresh milk, factory milk, whey | General quality defects | Koch’s plate method | IDF standard 100B: 1991, colony count MB* Vol. VI, 6.3.1 |
Aerobic spores of the Bacillus genus, e.g. Bacillus cereus | Fresh milk, UHT milk | Sweet clotting, slime formation, gas formation, swelling | Plate method using GCA agar | MB Vol. VI, 7.17.2 |
Anaerobic spores e.g. Clostridium tyrobutyricum, C. butyricum | Cheese milk | Late blowing in cheese, butyric acid formation | Nizo method, setting up dilution series, evaluation as per MPN method, Weinzirl sample | MB Vol. VI 7.18.2 7.18.3 7.18.4 |
Anaerobic spores e.g. Clostridium tyrobutyricum, C. butyricum | Cheese milk | Late blowing in cheese, butyric acid formation | Nizo method, setting up dilution series, evaluation as per MPN method, Weinzirl sample | MB Vol. VI 7.18.2 7.18.3 7.18.4 |
On account of the design features mentioned, it is possible to apply the prolong process developed by GEA and already successfully in use in several dairies. There is no further heat treatment apart from the necessary pasteurisation (IDF standard with no excessive heat load). When milk is temperature-treated to inactivate bacteria and spores (e.g. UHT, ESL) undesired side effects such as changes in flavor may occur and process costs increase.
Following bacteria separation, the drip whey can be remixed with the other whey instead of being used as animal feed or being disposed of altogether as was previously the case. Due to the long retention times and optimum growth temperatures, intense bacterial growth also takes place in the filtration equipment for concentrating the whey. When, for example, serum proteins are to be recovered from the clarified and skimmed milk in concentrated form (WPC, whey protein concentrate) by means of ultrafiltration, many dairies are meanwhile using bacteria removal separators. To meet the most stringent quality requirements, GEA bacteria removal separators can be used effectively for whey as well as concentrates. To sum up, efficiency levels of up to 90 % and often more can be achieved in relation to the total germ count.
GEA ecoclear: 3,000 – 25,000 l/h
CSI / CSE: 8,000 – 60,000 l/h
GEA proplus extends the ejection intervals of milk separators from 20 – 30 minutes to up to 90 minutes. This ensures added value, a significant increase in protein yields from the quantity of milk used and a clear reduction in fresh water consumption and waste water creation.
Even the best centrifuges cannot function optimally if they are not partnered with control systems of equal quality. For their range of separators and decanters, GEA offers standardized as well as tailor-made solutions for machine automation with many features to meet customer requirements.
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Is a FAT (Factory Acceptance Test) of your centrifuge not possible on site due to current travel restrictions, a very tight schedule or other urgent reasons? Are you generally looking for ways to make business processes more digital and to sustainably reduce costs and time?
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