# Membrane Filtration Techniques for Bacterial Removal in Milk

Topic radar · 67 documents · 2021-01-01–2026-10-09 · updated 2026-10-26

Canonical: https://slate.greyb.com/radar/membrane-filtration-techniques-for-bacterial-removal-in-milk/innovations

## In one minute

### A micrometre of pore size separates two industries
| Membrane and pore | Duty | What was measured |
|---|---|---|
| Ceramic, 1.4 µm | Bacterial and spore removal before the heat step | 2.17 log of *Bacillus licheniformis* spores; *Geobacillus* spores almost fully removed; total count down up to 2 log [1] [2] |
| Ceramic, 1.2 µm | Same, tighter | 4.57 log of *B. licheniformis* spores [1] |
| Ceramic, 0.8 µm and 0.45 µm | Shelf-life extension | About two weeks and three weeks of refrigerated life, with negligible loss of alpha-lactalbumin and beta-lactoglobulin [3] |
| Ceramic, 0.1 µm | Casein from whey protein | Retained all caseins; 0.2 µm let 1.4% casein through and whitened the permeate [4] |
| Polymeric, 0.1 µm | Fractionation | Not sterilising; every permeate sample grew bacteria within six days [2] |
| Ceramic, 0.05 µm | Serum protein from micellar casein, goat milk | 96.2% of serum protein removed over three stages; flux recovered to 99.2% after caustic and nitric cleaning [5] |

Trade coverage puts the bacterial-removal range at 0.8 to 1.4 micrometres with four to six logs of reduction, inside a chain that also includes pasteurisation and cold-chain discipline [6]. The measured numbers land in that band when the membrane is combined with heat: 5.6 log for microfiltration plus pasteurisation in Cornell's work, where microbial stability ran past 92 days [7], and 4.66 log in the 2013 trial that reached 60 to 90 days at 1.7 and 5.7 degrees Celsius [8].

1. [10.3168/jds.2018-14888](https://doi.org/10.3168/jds.2018-14888)
2. [10.1016/j.lwt.2021.113064](https://doi.org/10.1016/j.lwt.2021.113064)
3. [pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/42011119/)
4. [10.3168/jds.2016-11090](https://doi.org/10.3168/jds.2016-11090)
5. [10.1111/jfpe.13334](https://doi.org/10.1111/jfpe.13334)
6. [dairyfoods.com](https://www.dairyfoods.com/articles/98981-membrane-technology-improving-dairy-product-shelf-life)
7. [journalofdairyscience.org](https://www.journalofdairyscience.org/article/S0022-0302(06)72361-X/fulltext)
8. [journalofdairyscience.org](https://www.journalofdairyscience.org/article/S0022-0302(13)00703-0/fulltext)

### Bacterial control reaches buyers inside a complete line, and the line is what gets ordered
GEMAK's Turkish unit is filed as a whole set, from membrane skid through separator, homogeniser and filler, with a claimed 4 to 5 log spore reduction and at least 21 days of shelf life. APV describes the same shift in architecture terms, with microfiltration removing what heat treatment used to remove while reverse osmosis concentrates at lower energy than evaporation.


### Equipment builders in Turkey and China are patenting whole bacterial-removal lines
The most recent invention is a packaged drinking-milk unit. GEMAK, a Turkish processing-equipment maker, filed on a line built around 0.2 to 2 micrometre ceramic membranes that it says reaches 4 to 5 log reduction of Bacillus cereus spores, holds at least 21 days of shelf life, and processes 3 tonnes an hour on cow, goat or buffalo milk. The unit ships as a complete set: membrane skid, separator, homogeniser, standardiser, cream pasteuriser and control panel. Gemak already builds turnkey dairy plants from three manufacturing sites and sells into the UK, US, UAE and Canada.


### Spore surface chemistry changes what a given pore size removes
Spores are not little spheres that either fit or do not. B. licheniformis spores measured 1.37 to 1.59 micrometres long and 0.64 to 0.81 wide, yet some still passed a 1.2 micrometre membrane. Geobacillus spores, which are hydrophobic, clumped in the milk and were almost completely held back even at 1.4 micrometres.


### The order book is for protein and water, and bacterial removal rides along
MMPA began full operations at Ovid, Michigan in February 2026 after a January ribbon-cutting, adding ultrafiltered capacity. Byrne Dairy is putting $120 million into a Cortlandville expansion that adds ultrafiltered capacity and aseptic and ESL bottle lines.


### The established suppliers are putting their effort into efficiency and application support
Tetra Pak, GEA and Alfa Laval are positioning membranes as plant-performance levers judged on water, energy and overall efficiency. GEA showed pilot units at IFT First in July 2026 framed around reducing energy, water and other inputs. APV argues for integrated architectures where microfiltration takes over what thermal treatment used to do and reverse osmosis concentrates at lower energy than evaporation.


### The fouling layer ends up deciding what passes
Munich's group found that deposits reduce flux and in many cases dominate a system's retention characteristics. Deposit thickness and porosity vary along the module because of pressure drop in crossflow, and casein micelles deform as filtrate flows toward the surface. The deposit is part of the separation, so the membrane's rejection is not a fixed property of the sheet.


### The economics being underwritten moved within five months
Capital committed in this window was priced against a whey market near its top.


## Overview


Bacterial removal by membrane is a specified, legally embedded step in dairy processing, and it is the least measured part of the technology it belongs to. The claims about bacterial removal are abundant and the measurements are few. The research, the capital and the supplier messaging have all moved toward protein fractionation, water recovery and cleaning cost, and bacterial removal now travels with that equipment as a property rather than as a purchase in its own right.


## Research

### Cold operation buys run length and changes the product
Temperature is the setting that pays twice. In a feed-and-bleed rig built to mimic an industrial plant, 0.1 micrometre filtration stopped on bacterial counts at 420 minutes at 55 degrees and ran past 1,440 minutes at 10 degrees.


### A fractionation line is a two-stage cascade with diafiltration
The standard build is 0.1 micrometre ceramic at 50 degrees, with the permeate concentrated on a 10 kilodalton ultrafiltration membrane. Cork's 2025 pilot ran it at 8.9 degrees or 50 degrees to produce a whey-dominant base whose casein profile sits closer to human milk, and a China Agricultural University team with Mengniu and Pucheng ran the complementary version at pilot scale, co-enriching beta-casein and whey protein.


### The whey train takes water out before it splits protein
Reverse osmosis runs first. At Mammen Dairies it strips about 75% of the water from whey, and the concentrate goes into infant formula and sports nutrition. At Arla's Danish site it is a polisher toward zero discharge, recovering 47 tonnes of water an hour and taking 65 tonnes an hour of whey to 18 tonnes at 23.5% solids. Ultrafiltration follows, to WPC35 through WPC80 and whey protein isolate, with microfiltration ahead of it to strip fat and cheese fines. Reverse osmosis rejects dissolved and suspended solids; ultrafiltration holds back protein and fat while lactose, salts and acids pass.


### Cleaning is engineered into the machine
Every line here is specified with its clean-in-place loop, and the savings are measured at the plant. Molkerei Ammerland reported 48% less water, 77% less energy and 15% less cleaning time across four plants, around 180,000 euros a year and payback under two years. A whey ultrafiltration programme cut clean-in-place time by 360 hours a year, and a ceramic microfiltration unit brought caustic cleaning cost from 420,000 dollars to under 240,000. GEA reported halving water and power in membrane plant cleaning, and dairy cleaning effluent can return 75% of its cleaning solution through ultrafiltration and nanofiltration.


### The integrity test exists and comes from sterile filtration
The hardware to prove a membrane still retains what it should is mature. For sterilising-grade cartridges, a bubble point test alone did not fail until a laser defect reached 30 to 60 micrometres, corresponding to log reduction values of 4.0 to 4.5, so it is paired with a gas-liquid diffusion test. Pall's dairy modules ship with 100% bubble point integrity testing, a 3-A sanitary certificate, steam sterilisation compatibility and operating lives beyond ten years. The verification discipline is therefore available on equipment already sold into dairy; what is missing is a dairy plant publishing log reduction across a membrane's working life.


### A heat step remains in every legal line
Microfiltration lowers the load a pasteuriser has to handle, and that is what buys the milder heat treatment and the better flavour. SPX describes removing bacteria and spores from skim milk, treating the cream separately so it is not overheated, then applying legal pasteurisation, with several weeks of downstream refrigerated life. Federal rules require pasteurisation for milk in final package form for direct consumption, and the 2025 Grade A Pasteurized Milk Ordinance is the standard states adopt. The membrane is a pre-treatment inside that frame.


### What is built, and where the gaps are
Running hardware spans four types: ceramic tubular microfiltration at 0.8 to 1.4 micrometres for extended-shelf-life milk, 0.1 micrometre ceramic cascades with a 10 kilodalton ultrafiltration stage for casein and whey fractions, reverse osmosis and ultrafiltration trains in commercial whey plants, and clean-in-place systems with measured water and energy savings. Adjacent to these, FrieslandCampina and Vito are developing ceramic nanofiltration with a grafted surface layer to replace ion-exchange demineralisation of whey, a conversion argued on operating cost, chemical use and wastewater.


## Market

### The bacterial claim in the market traces to the supplier making it
SPX FLOW's global technical sales leader called microfiltration a cornerstone technology for shelf life because it physically removes bacteria and spores before thermal treatment. The claim and the sale have one origin, and the same article gives the 0.8 to 1.4 micrometre range that the measured literature supports only when a heat step follows.


### Grant and recovery money sits inside the capex, so the pipeline is policy-timed
The Dairy Business Innovation Alliance has awarded nearly 320 grants worth more than $26.5 million since 2018, including one that installed an ultrafiltration membrane system for quark and cream cheese production. Michigan's economic development corporation backed both the Ovid expansion and MMPA's purchase of the Remus plant, and Bakoma's line runs under a national recovery plan component.


## Strategy

### The research front has moved to fractionation, with dairies as co-authors
The active groups are working on what comes out of a 0.1 micrometre membrane, not on how many bacteria a 1.4 micrometre membrane holds back. Cork ran a pilot at 8.9 or 50 degrees to make a whey-dominant base whose casein profile sits closer to human milk, and a China Agricultural University team with Mengniu and Pucheng co-enriched beta-casein and whey protein at pilot scale. Olsztyn has taken the same cold-microfiltration retentate into rennet gels, testing whether the fraction still behaves like milk when it is made into cheese.


### Fresh capacity is arriving through cooperatives and grant money, with the growth in Asia
In the United States, MMPA added ultrafiltered capacity at Ovid, Michigan and bought the Remus plant outright, and the Dairy Business Innovation Alliance has awarded nearly 320 grants worth more than $26.5 million since 2018, with at least one going to an ultrafiltration installation. Byrne Dairy is putting $120 million into a Cortlandville expansion that adds ultrafiltered capacity and aseptic and ESL bottle lines. In Poland, Bakoma tendered for an ultrafiltration line funded through the national recovery plan.


### The measured evidence for bacterial removal is not being renewed
The effort at the plant is going into lines, economics and throughput, and the microbiology that would show a membrane still removing what it should is lagging. The newest independent plant result is about two to three weeks of refrigerated shelf life from 0.8 and 0.45 micrometre membranes under a full hygiene and hazard-control system. That is shorter than what Cornell reached in 2013 with microfiltration plus pasteurisation, 60 to 90 days at 1.7 and 5.7 degrees.


### The capacity to prove removal is not accumulating where the claims are made
Bacterial removal is becoming a feature of complete lines sold into markets that want long-life milk, and a manufacturing detail in plants justified by protein value and water recovery elsewhere. The supply side is aligning behind that split: application centres and pilot fleets in the West, packaged ESL units with a bacterial claim out of Turkey and China.


## Areas

- Market & Ecosystem: Adoption & Research · 28 documents
- Equipment & Operations: Plant Efficiency · 12 documents
- Whey Valorization & Byproduct Streams · 10 documents
- Milk Processing: Shelf-Life & Safety · 8 documents
- Protein Fractionation & Standardization · 8 documents