I notice milk frozen immediately after purchase and then weeks later thawed doesn't last very long, a few days a most, before it curdles (US Costco organic 1%).

I notice milk frozen immediately after purchase and then weeks later thawed doesn't last very long, a few days a most, before it curdles (US Costco organic 1%). We also get organic UHT chocolate milk in small boxes which lasts a few months. UHT organic heavy cream in small boxes last some months as well.