Sure there are, food is traded on commodities markets just like everything else.
Just because something is traded doesn't make it an appreciating asset. In the case of commodities, they're typically traded as risk management instruments, not something that inherently provides returns.
1. Manipulates interest rates directly affecting house prices
2. Changes tax rates depending on housing (mortgage interest)
3. Buys mortgages
4. Zones areas which can restrict or increase supply based on policy.
Yes, if they didn’t do any of these, people wouldn’t blame government policy and we’d see what a functioning market results in.