Nothing will happen if you don't pack it in your checked luggage. Instead, keep it in your purse or carry-on cabin luggage. Also, remember to take it out of the fridge before leaving your house. Assuming you will be traveling in an air-conditioned car and the airport will be fully air-conditioned, there should be no issues. Just be sure to keep it away from direct sunlight. I'm sure you are already aware of this, especially for a long flight.