Background: Not only do infant formulas lack nutritional components supplied in breast
milk, they lack a variety of maternal immune components normally transferred through breast milk,
including microbial agglutinins. Bacterial aggregation by these agglutinins potentially reduces the
likelihood of infection and is a critical step in the formation of the normal ecosystem of the infant’s
gut, which is vital to proper immune system development.
Objective: Given the need for better sources of breast milk for children who cannot receive their own
mother’s milk, the effect of High Temperature, Short Time (HTST) pasteurization and Holder pasteurization
methods on agglutinins in human breast milk was assessed.
Methods: For this purpose, a small scale HTST pasteurization apparatus and protocol was created
and validated. Bacterial aggregation was assessed indirectly by measuring initial changes in CFUs
following post-pasteurization addition of exogenous bacteria, with less increase in CFUs being indicative
Results: Raw milk and Holder pasteurized milk resulted in the fewest CFUs, with no difference observed
between the two preparations. Interestingly, HTST pasteurized breast milk did not result in
fewer CFUs than Holder pasteurized milk (p = 0.03), suggesting that the Holder method of pasteurization
is at least as effective as HTST pasteurization at preserving bacterial agglutinins in human
Conclusion: Although more CFUs were observed in the assay using boiled human breast milk than
any other milk preparation, the most CFUs were observed with infant formula, suggesting a propensity
for that material to support uncontrolled planktonic bacterial growth.