Security
The contracts are deployed from the original PoolTogether PrizePool factory.
This factory contract has been up for a year and half and built the same contracts that have secured hundreds of millions of dollars.
Audits
At least three audits have been conducted on these contracts, two of which were done by Open Zeppelin. For more information please see the official PoolTogether documentation. PoolTogether V3 - Audits & Testing