Answer:
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