Home Pasteurization Guide

Safe methods for pasteurizing donor breast milk at home

What is Pasteurization?

Pasteurization is a heat treatment process that kills harmful bacteria and viruses in breast milk while preserving most of its nutritional and immunological benefits. Home pasteurization provides an extra layer of safety when using donor milk.

While pasteurization reduces some beneficial enzymes and antibodies, it significantly improves safety by eliminating pathogens like HIV, hepatitis, and harmful bacteria.

Should You Pasteurize Donor Milk?

Recommended If:

  • ✓Donor is not ID-verified or you don't know their health status
  • ✓You don't know the donor personally
  • ✓Your baby has a compromised immune system
  • ✓Your baby is premature or medically fragile
  • ✓You want maximum safety assurance

May Not Need If:

  • •Donor has shared recent health information with you directly
  • •You know the donor personally and trust their health
  • •Donor has verified seller badge on platform
  • •You want to preserve maximum antibodies/enzymes

Note: Even with trusted donors, pasteurization adds extra safety.

Holder Pasteurization Method

The Holder method (62.5°C / 145°F for 30 minutes) is the gold standard used by milk banks worldwide. It effectively kills pathogens while preserving most nutritional properties.

Equipment Needed

  • Large pot or stockpot
  • Accurate food/candy thermometer (readable to 145°F)
  • Glass bottles or heat-safe containers for milk
  • Timer
  • Ice bath (large bowl with ice water)
  • Trivet or rack to keep bottles off pot bottom

Step-by-Step Instructions

  1. 1
    Thaw milk: Thaw frozen milk completely in refrigerator (never microwave or hot water)
  2. 2
    Prepare containers: Pour milk into clean glass bottles, leaving 1 inch of space at top. Cap loosely.
  3. 3
    Set up water bath: Fill large pot with water to cover milk bottles by at least 2 inches. Place trivet/rack in bottom.
  4. 4
    Heat water slowly: Heat water to 145°F (62.5°C). Monitor temperature constantly with thermometer.
  5. 5
    Add milk bottles: When water reaches 145°F, carefully place bottles in water bath.
  6. 6
    Maintain temperature: Keep water at 145°F (±2°F) for exactly 30 minutes. Adjust heat as needed. Check temperature every 5 minutes.
  7. 7
    Cool rapidly: After 30 minutes, immediately transfer bottles to ice bath. Cool to 40°F or below within 20 minutes.
  8. 8
    Label and store: Label bottles as "Pasteurized" with date. Refrigerate immediately (use within 24-48 hours) or freeze (use within 3 months).

Critical Safety Tips

Temperature is critical: Milk must reach and maintain 145°F. Too low won't kill pathogens; too high destroys nutrients. Use an accurate thermometer.
Time matters: 30 minutes at temperature is required for effective pasteurization. Don't rush or skip this step.
Cool quickly: Rapid cooling prevents bacterial growth. Get milk to 40°F within 20 minutes of finishing pasteurization.
Never microwave: Microwaving creates hot spots, destroys nutrients unevenly, and can scald baby. Always use water bath method.
Use within 48 hours: Once pasteurized, milk should be refrigerated and used within 24-48 hours, or refrozen for up to 3 months.

How Pasteurization Affects Milk

What's Reduced:

  • ↓Some antibodies (IgA reduced by ~20%)
  • ↓Lipase enzyme activity (~60% reduction)
  • ↓Some vitamins (B1, B6, C, folic acid)
  • ↓White blood cells (completely destroyed)

What's Preserved:

  • ✓Proteins and amino acids (~90%)
  • ✓Fats and fatty acids (mostly intact)
  • ✓Carbohydrates and lactose (100%)
  • ✓Most vitamins and minerals
  • ✓Growth factors

Bottom line: Pasteurized breast milk is still far superior to formula and retains most benefits.

Pasteurization FAQs

Can I use a sous vide machine?

Yes! Sous vide machines maintain precise temperatures, making them excellent for Holder pasteurization. Set to 145°F and immerse sealed bottles for 30 minutes.

Will pasteurized milk taste different?

Some babies may notice a slight difference, but most accept pasteurized milk without issue. The taste change is minimal compared to formula.

Can I pasteurize milk in storage bags?

It's not recommended. Most storage bags aren't designed for heat and may leach chemicals or break. Always transfer to glass bottles first.

How long does pasteurized milk last?

Refrigerated: 24-48 hours. Frozen: Up to 3 months (though some nutrients degrade over time). Always label with pasteurization date.

Learn More About Safety

Pasteurization is just one part of safe milk sharing

Safety & Trust GuideShipping & Handling