Oxygen can frozen solid at a Temperature of 54.36 K. The K stands for Kelvin and is the absolute zero (lowest temperature that is theoretically possible). 1 Kelvin is -272.15 degrees Celsius. A temperature of 54.36 K would be 54.36 degrees above the absolute zero point, meaning -218.79 degrees Celsius.
PS: Eating solid oxygen would freeze you to death.