Flying with Milk?

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What are the laws with OZ? I'll be flying all day and have NO IDEA how I can travel with milk and keep it fresh, and how much is acceptable? I exclusively pump feed and am so stressed about this! We will be taking two flights first 3 hours then a 3hr layover till next flight then a 2 hr flight after that! What are the security rules on liquids and how can I safely and freshly pack and store it!! Lawd help me!!