"cooking foods to their proper temperature to ensure that bacteria are killed before the food is eaten."

The answer in the space provided is the preserved bacteria. It is because most foods are chilled in order to prevent the food from spoiling but in the same time, the bacteria that resides in the food, especially in meat products, are being preserved. In order for it to be killed, it is best to cook it thoroughly and properly, in order for the bacteria to be killed and safe for the people to consume.

Carbon monoxide is the answer: )