Answer:
External factors can be described as factors which give rise to a situation from outside. Internal factors bring a change or give rise to a situation from internal conditions.
External Factors:
Temperature of food storage during processing.
Humidity of the storage environment
Presence of gases, such as CO2, during packaging
Preservatives, such as salt and sugar
Handling of food by manufacturers
Internal Factors:
pH of the food
Presence of antimicrobial compounds
Nutrient content (Such as vitamins and minerals)
Moisture content or water activity
Protective structure of food, such as feathers, hide and skin