Microfiltration of human milk to reduce bacterial contamination
The present invention relates to a method for treating raw human milk to produce treated human milk having undetectable levels of bacteria. The milk is skimmed to produce skim human milk then subjected to microfiltration to yield a filtrate which has undetectable levels of bacteria, including Bacillus cereus . The resultant human milk can be further processed, used and/or sold.
1. A method for treating raw human milk to obtain microfiltered human milk having lower bacteria content compared to raw human milk, comprising:
(a) providing raw human milk;
(b) separating the raw milk into a cream fraction and a skim milk fraction, wherein the skim milk fraction contains about 1.0% to about 0.1% fat content;
(c) pre-filtering the skim milk fraction using a filter aid through one or more pre-filters to produce pre-filtered skim milk, wherein said filter aid is added to said skim milk fraction in a concentration of from about 20 g/L to about 50 g/L, and wherein said filter aid has a permeability of from about 0.100 D to about 0.300 D; and
(d) microfiltering the pre-filtered skim milk obtained in step (c) through one or more microfilters to obtain microfiltered human skim milk.
2. The method of claim 1 , wherein the filter aid is diatomaceous earth.
3. The method of claim 1 , wherein the filter aid is added to the skim milk fraction obtained in step (b) to form a slurry.
4. The method of claim 3 , wherein the slurry is passed through the said pre-filter to form the said pre-filtered skim milk.
5. The method of claim 1 , wherein the microfiltered human skim milk obtained in step (d) further comprises the step of: concentrating said microfiltered human skim milk by ultrafiltration.
6. The method of claim 5 , wherein the concentrated microfiltered human skim milk has about 5% to about 15% protein content.
7. The method of claim 1 , wherein the method further comprises adding human milk cream into the microfiltered human skim milk to produce a whole human milk product.
8. The method of claim 1 , wherein the bacteria comprise Bacillus species.
9. The method of claim 1 , wherein the microfiltered skim milk fraction has no more than 10 1 bacteria per milliliter.
10. The method of claim 3 , wherein the filter aid in the skim milk fraction is about 2% w/v to about 5% w/v.
11. The method of claim 1 , wherein the microfilters having an average pore size sufficient to reduce the bacterial content of the skim milk.
12. The method of claim 11 , wherein the average pore size of the microfilters is about 0.2 to 1 micron.
13. The method of claim 1 , wherein the pre-filters comprising an average pore size of about 1 to 10 microns.
14. The method of claim 1 , wherein said filter aid has a concentration of about 50 g/L and a permeability of about 0.300 D.