How can the shelf life of food be so long?

The aluminium can is the most popular material for food packaging.

 

Introduction

 

Hello. Today, we will explore the reasons why the shelf life of food can be extended. While shopping, there are times when we are surprised by the manufacturing date of a product, often when it was made a long time ago. Even more surprising is when you check the expiry date and it's specified as two years from the manufacture date. Most foods on our table, like soup or stew, spoil within a week, let alone a year. So, how can the shelf life of food be so long? Let's delve into this.

 

Summary

 

1. The key factors that enable the long-term storage of food are packaging and processing methods. Particularly, excellent packaging that blocks oxygen and moisture is crucial, and for this, Al (Aluminum) is the most effective material.

2. Although Al (Aluminum) has excellent oxygen, moisture, and bacterial blocking properties, it can be damaged by sharp objects, so it is used in combination with other materials. To balance cost saving and performance, a deposition method is used, where Al is vaporized and attached to the film. The produced deposition film provides a compromise both in terms of cost and performance.

3. Aluminum used in food packaging is difficult to recycle and can be harmful to the environment, so both consumers and producers need to work towards finding environmentally friendly alternatives.

 

Methods for Long-Term Storage

 

Methods for long-term storage often involve treating the food, but the primary role is played by packaging and processing methods. Key to this is isolating the food from the external environment. For example, food can become rancid when it reacts with oxygen, and reactions such as hydrolysis can occur when it reacts with moisture. Also, moisture can contribute to microbial growth, affecting food preservation. To prevent this, it's important to use packaging materials that excellently block oxygen and moisture, such as Al and EVOH, among which Al is the most effective.

 

Simultaneously with packaging, it's crucial to enhance the preservation of the food by processing. Sterilization is a representative method. Sterilization is done by pressurized heating at high temperatures to remove bacteria that harm the food. It targets bacteria that can be exterminated at specific temperatures, mainly sterilizing at 121 degrees Celsius to target bacteria, including spores, which perish at this temperature. Al (Aluminum) Al refers to aluminum, which is commonly seen in our daily lives in the form of aluminum foil.

 

However, aluminum foil is too thick for food packaging, so it's usually used in thinner thicknesses like 6, 7, 9, 12㎛. Al has excellent oxygen and moisture barrier properties, as well as bacterial barrier properties. On the other hand, it needs some improvement in its resistance to pinholes, i.e., damage from sharp objects, so it's used in combination with other materials like NY and CPP. Deposition When using Al in film form, a large amount of Al is required, which can be expensive. To save costs while maintaining similar performance, the deposition method was devised. This method involves vaporizing Al and attaching it to the desired substrate.

 

The resulting deposition film provides a balance between cost and performance. The silver shine of Al appears more glittery in the deposition film. There is also a transparent deposition method, which forms a transparent coating through Al deposition and additional processing. This has a slightly lower oxygen and moisture blocking capacity than Al, but it's sufficient for sterilized food.

 

Conclusion

 

We've looked at the essential components of food packaging for long-term storage. Hopefully, this gives you an answer to the question, "How can the shelf life of food be so long?" Remember that when Al is mixed into packaging, it can't be recycled and is virtually non-degradable, posing a threat to our environment despite its convenience. While there is ongoing research into recycling and other areas, it's still in progress, and efforts from consumers and producers alike are needed.