Several conservation methods have been used to prevent food spoilage and food poisoning ever since ancient times. These are; salting, drying and smoking. Nowadays, chilling, freezing, dehydration and canning methods are used.
You can see the names of food conservation methods below;
Preparing foods under hygiene rules
High temperature

Boiling
Vapour application
Pasteurization

Low temperature

Chilling
Freezing
Dehydration

High Osmotic Pressure

Concentrated  sugar
Salting

Chemical additives

Organic acids
Smoking
Fermentation

Radiation

UV lights
Ionized radiation

Although  scientists have made great strides in milk hygiene and technology after Second World War, milk-borne zoonosis diseases are still very important in human health. That is why milk hygiene and control is very important part of the food science.
Milk is contaminated by bacteria and viruses via unhealthy animals, people hands, milking utensils or water. [...]

Cooking Suggestions

To prevent pathogen growing, the temperature of hot foods have to be minimum 60°C (140°F) and to measure the temperature, digital thermometer have to be used.
The temperature of the cold foods have to be under 4°C (40°F). Together with digital termometer, fridge termometer has to be used.

Perishable foods have to be kept beside danger [...]