Food spoilage is classified into three types namely chemical, biological and physical.
1) Physical spoilage. A pack of banana chips should arrived to target customers in its peak condition. Every single or most of the chips should be whole and crispy. Physical damage is change in original form due to external forces during handling, transport, storage and display on grocery shelves. No one is willing to buy a crumbled potato chips, mashed cake or a leaking juice.
2) Chemical spoilage. Sunlight and presence of oxygen contribute to chemical spoilage. Oxygen causes rancidity to oily products while sunlight causes fading of colors. The product might also absorb unwanted chemical or odors from surrounding environment.
3) Biological spoilage. Cause by rodents ants and cockroaches. Rodents is the most notorious cause of its ability to open foods packed in plastics and plastic laminated polymers. This type of spoilage can also be cause by species invincible to the native eye – microorganisms such as bacteria and fungi.
Foods are processed and packed to prevent the three types of food damage. The two alone often suffice to prolong the shelf life for considerable amount of time.
1) Reaction to light will not occur if the package type is translucent – no light can pass through it.
2) Rancidity reaction will not take place if the packaging is tight enough to resist oxygen entry. Common PE bags resist water entry but allow oxygen to pass through.
3) Spoilage cause by microorganisms can be arrested through proper heat treatment, sanitation and proper packaging. All contaminants should be killed during heating, all sort of microbial entry should be prevented by means of good hygiene and the package should not be permeable either.
4) Chemical and odor absorption can be prevented by proper packaging. If the packaging does not permit oxygen entry then it will not allow the passage of other substances. The package should be inert to prevent any reaction to its contents
5) How about physical damages? Most chip packages are pumped up with carbon dioxide or nitrogen gas. The purpose is to exclude oxygen thus preventing rancidity and loose of crispiness. The blow-up package also serve as protection to external pressure. Another way is the use of hard carton and neat content arrangement. The Pringles is using a thick cylindrical carton. All the chips are round concave,neatly stacked, have the same sizes and fits perfectly to container. Larger softdrinks are now using unbreakable PET bottles. Expensive wines come in a secondary carton pack. The purpose is not just aesthetic but also to avoid breakage in case of accidental drop.
If proper processing and packaging are done, any kind of food preservative is not needed to prolong food storage life.