Excessive heat denatures proteins, breaks emulsions, removes moisture from food and destroys nutrients such as vitamins.
However, excessive coldness, such as freezing, also discolors fruits and vegetable, changes their texture and/or cracks their outer coatings to permit contamination by organisms.
Food under pressure will be squeezed and transformed into unnatural conformation. The compression will likely break up the surface structure, release degradative enzymes, and expose the damage food to exterior microbial contamination.
Many health officials consider physical factors to include such things as sand, glass, wood chips, rat hair, animal urine, bird droppings, insect parts and so on. These things may not spoil the food, but they do present hazards.
Some these foreign substances do lead to spoilage.
Furthermore, insects and rodents can consume and damage stores foods and insect can lay eggs and leave larvae in the foods, causing further damage later.
Such foods are no longer reliable since they contain hidden contaminants.
The attacks of the by insect and rodents can also contaminate foods further with microbial infections.
Food Spoilage and Physical Factors
