Centrifuge

Bacteria Removal Separators for Milk and Whey

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.

The application spectrum ranges from 1-stage, 2-stage and special bacteria separation from drinking milk through variable bacteria separation to cheese-making milk, right up to treatment of whey concentrate.

Increased protein yield with GEA proplus

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.

Optimum design for the efficient removal of spore formers

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%.

Taking samples

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 ofUsed in (product)Damage causedName of methodReference method
Total bacteria countFresh milk, factory milk, wheyGeneral quality defectsKoch’s plate methodIDF standard 100B: 1991, colony count MB* Vol. VI, 6.3.1
Aerobic spores of the Bacillus genus, e.g. Bacillus cereusFresh milk, UHT milkSweet clotting, slime formation, gas formation, swellingPlate method using GCA agarMB Vol. VI, 7.17.2
Anaerobic spores e.g. Clostridium tyrobutyricum, C. butyricumCheese milkLate blowing in cheese, butyric acid formationNizo method, setting up dilution series, evaluation as per MPN method, Weinzirl sampleMB Vol. VI 7.18.2 7.18.3 7.18.4
Anaerobic spores e.g. Clostridium tyrobutyricum, C. butyricumCheese milkLate blowing in cheese, butyric acid formationNizo method, setting up dilution series, evaluation as per MPN method, Weinzirl sampleMB Vol. VI 7.18.2 7.18.3 7.18.4
* Handbuch der landwirtschaftlichen Versuchs- und Untersuchungsmethodik, Methodenbuch Band VI [Manual of agricultural experimental and test methods, method book volume VI] published by the VDLUFA [Verband Deutscher Landwirtschaftlicher Untersuchungs- und Forschungsanstalten – Association of German Agricultural Test and Research Institutes]

Double bacteria removal

Fresh milk with a longer shelf life thanks to GEA prolongThe double bacteria removal with two bacteria removal separators reliably removes somatic cells, bacteria and spores from the milk. The result: the first fresh milk that combines natural flavor and full vitamin content with a long shelf life. The GEA prolong process can be integrated profitably into a broad spectrum of dairy concepts because the double bacteria removal can be used without difficulty in the production of further products such as cheese and milk powder.
Centrifuge-Clarifier-CSI-Milk-Whey-top-view

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.

Whey

Bacteria separation of wheyBacteria separation is likewise recommended downstream of the cheese-making process since the whey are processed at temperatures conducive to optimal bacterial growth.
Centrifuge - Clarifier CSE for Milk or Whey

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.

Machine Portfolio

Technical Features & CapacitiesThe ecoclear is by default equipped with the GEA proplus system, which is optionally available for types CSE and CSI.
Capacities
Centrifuge - Clarifier GEA ecoclear for Milk or Whey

GEA ecoclear: 3,000 – 25,000 l/h
CSI / CSE: 8,000 – 60,000 l/h

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