Yes crumble topping can be frozen.
When you need to store crumble topping you should freeze the crumble topping for best results.
When freezing crumble topping the crumble topping should be stored in a freezer proof airtight container or tightly sealed in a freezer bag.
You can keep the frozen crumble topping for at least 3 months.
The crumble topping will be okay after 3 months in the freezer but for best results with the crumble topping you should use the frozen crumble topping within the 3 months.
The longer the crumble topping stays frozen the less fresh it becomes.
So use the crumble topping within 3 months of freezing it.