International Board of Certified Lactation Consultant (IBCLC) Practice Exam

Which component of human milk is most resistant to pasteurization and freezing?

1. Immunoglobulin M

2. Living cells

3. Human milk oligosaccharides

4. Lactoferrin

The correct answer is: Human milk oligosaccharides

Human milk oligosaccharides (HMOs) are the correct choice as they exhibit remarkable stability under both pasteurization and freezing processes. HMOs are complex carbohydrates that serve as prebiotics and play a crucial role in the infant's gut health, immune system development, and protection against pathogens. The stability of HMOs during pasteurization and freezing is significant because these processes are often used to ensure the safety of donor human milk while preserving as much of its beneficial properties as possible. Unlike living cells or certain proteins, which can be damaged or diminished through these methods, HMOs primarily retain their structure and functionality. In contrast to HMOs, other components such as immunoglobulin M and lactoferrin can be affected by heat treatment and may lose some of their biological activity. Living cells are inherently more susceptible to damage through both pasteurization and freezing due to their complex structures and metabolic activities, resulting in a loss of viability. The robust nature of HMOs, in relation to pasteurization and freezing, underscores their significant role in the bioactive composition of human milk, enhancing the importance of preserving them in the context of feeding practices for infants.