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We supply membranes and modules for many applications in
Milk processing and Cheese production,
concentrating, fractionating and separating milk components.
MICROFILTRATION OF MILK
Skim milk can be microfiltered (1.4 micron pore size)
to remove spoilage bacteria and spores, extending its shelf life.
Using a smaller pore size filter (0.1 micron),
skim milk can be microfiltered to retain casein
but filter out other macromolecules,
making it an ideal milk for process cheesemaking.
Microfiltration can be used at a fluid milk plant
prior to pasteurization to reduce microbial counts.
This process produces a product with organoleptic
and chemical properties similar to traditional HTST milk,
without the “ cooked taste” that often results from other
ESL milks like those obtained through ultra-pasteurization.
The process involves preheating and separating raw milk,
with the resulting skim milk microfiltered and separated into a
bacteria-poor skim milk (permeate) and a bacteria-rich skim milk (retentate).
Skim milk is used because the fat globules are similar in size
to bacteria and are therefore retained by the membrane.
The retentate can be either removed from the process
or it can be mixed with a standardized quantity of cream
(if a fat-containing milk product is desired).
This mix is then sterilized by high-heat treating at 240°F for 4 seconds
and reintroduced to the permeate. The reblended milk is homogenized,
pasteurized and packaged. Because less than 10% of the milk is heat treated
at the high temperature heat treatment, the result is a product with a
fresh taste and up to 45 days shelf life when stored below 43°F.
Four basic types of membrane filtration present potential applications
for the dairy industry:
reverse osmosis (RO),
nanofiltration (NF),
ultrafiltration (UF) and
microfiltration (MF)
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