Store the entire container upside-down in the fridge. In case it might leak, I sit it on a whipped topping container lid (who doesn't have one of those laying around.) I've had it stay fresh for longer than a month past expiration date.
By Beth from OH
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Store the cottage cheese upside down. You will find it will stay fresh far longer.
If you want cottage cheese to last for a long time, store it upside down in your fridge. Somehow this keeps bacteria that causes spoilage at bay - I have opened six week old cartons and they are still fresh.
Storing your cottage upside down in the fridge can help to extend its shelf life. This is a page about storing cottage cheese upside down.