Contamination of expressed human milk can occur during which stages?

• A. Milk expression only
• B. Storage only
• C. Preparation and mixing of ingredients
• D. All of the above

Answer: (D)

Contamination risk exists at every stage of handling expressed human milk, not just one moment in the process. When milk is expressed, bacteria from unwashed hands, dirty pump parts, or contaminated containers can enter the milk. During storage, using unclean bottles or surfaces and keeping milk at improper temperatures can allow bacteria to grow or be introduced. In the preparation and mixing of ingredients, contamination can occur if sterile technique isn’t maintained—unsafe water, unclean utensils, or contaminated fortifiers or diluents can introduce pathogens or other contaminants. Because expressed milk isn’t sterile, careful hygiene and proper handling at expression, storage, and preparation are all important to minimize contamination.