Sterilization in plastic containers

Everything you need to know about sterilization of food in plastic containers

Sterilization in plastic containers

Is plastic packaging the best choice for my new product that I plan to introduce to the market? Does this material have the capacity to withstand the elevated temperatures required for pasteurization and sterilization processes? We will explore the answers to these questions in this article.

Plastic containers for preserves and ready meals

In linguistic and material science references, “plastic” is defined as a category of synthetic substances which can be easily molded and are mainly composed of long chain polymers that originate from petroleum sources. The term “plastic” itself is rooted in the concept plasticity, a property, which is a characteristic referring to a material’s capacity to undergo deformation without sustaining damage or fracturing.

When we speak of these types of containers, we refer to the material it is made of. Since plastic has a cool story of how it came to be and how we use it today, let’s take a quick look at its history!

Did you know how plastic containers were discovered and then became popular?

Although certain advances had already been made in the invention of plastic, it was not until 1860 that this material had its beginnings. It began in the United States, when a billiard ball manufacturer offered a $10,000 prize to anyone who could come up with a new product to replace ivory used in the manufacture of billiard balls because it was a component that was becoming scarce.

Finally, John Hyatt won that prize money because he invented celluloid, which is a plasticized derivative of cellulose, almost transparent and very elastic. In turn, this material gave rise to the film industry.

In 1907, Leo Baekeland invented the first thermosetting plastic, called Bakelite, which had insulating qualities and was resistant to moderate heat, acids and water. Bakelite was widely used to build the external structures of electrical devices, such as telephones. From that point on, scientists from all over the world began to investigate, giving rise to new theories and creating the polymers we know. Most of today’s food containers are manufactured on the basis of these scientific developments.

Tipos de envases de plástico para la esterilización de conservas y platos preparados

Types of plastic containers

Different types of plastic containers are used in the food industry. Current European Union regulations establish symbols with numbers that indicate which containers are safe for use with food and which are not suitable. Containers that are completely safe for use with food are:

  • 01 PETE. Polyethylene terephthalate, used for liquids such as soft drinks or mineral water.
  • 02 HDPE. High density polyethylene, used for hermetically sealed bags and milk or juice containers.
  • 04 LDPE. Low density polyethylene, used for freezing food.
  • 05 PP. Polypropylene, which should be used to manufacture plastic containers that will contain food.

All other plastics (03 PVC. Polyvinyl chloride, 06 PS. Polystyrene, 07 OTHER. Polycarbonates) should be avoided since several scientific studies have shown that they transfer bisphenol A (BPA), a compound known to disrupt endocrine functions and potentially link to cancer and other health issues. Likewise, it has been proven that this component is associated with cancer.

In the specific context of gourmet preserves and ready meals, the plastic containers that are normally used are trays, bottles and pouches.

These containers are usually made of polypropylene, which is a thermoplastic polymer identifiable by the number 5 and the PP acronym. This polymer is favored for its adaptability to various food preservation processes like pasteurization, sterilization, and freezing, owing to its resilience to a broad temperature range from -20ºC to 120ºC, water resistance, and ability to withstand both acidic and alkaline environments.

Moreover, polypropylene is recyclable, in addition to being safe for dishwasher and microwave use due to its chemical stability, as it is very stable to temperature changes and resistant to chemical agents.

Its lightweight, non-deformable, and impermeable nature, coupled with the absence of BPA and phthalates, enhances food preservation by minimizing the risk of external bacterial contamination.

It’s important to recognize that not every plastic material can withstand the processes of pasteurization or sterilization in an autoclave. We recommend diligently reviewing the technical specifications for each plastic option at your disposal, consulting with manufacturers to verify these details, and selecting the container that best aligns with the needs of your product.

Ventajas y desventajas de los envases de plástico para platos preparados

Advantages and disadvantages of plastic containers

A common concern when selecting plastic containers for products is the fear that they might not endure high temperatures. However, this concern is now disproved because, as we explained at the beginning of this article, there are plastics that can withstand both high and low temperatures.

Beyond temperature resistance, plastics face scrutiny for their environmental impact. Most of the plastics in widespread use are derived from fossil fuels, take centuries to degrade, and despite increasing rates of recycling, the truth is that there’s still significant progress to be made in waste management.

When comparing plastics to alternatives like glass, it’s worth noting that plastic tends to be more porous, making it less suitable for repeated use. However, plastic containers offer a significant advantage in terms of weight, as they are, on average, four times lighter than containers made from other materials. This lightweight nature allows for the same volume of food or beverage to be packaged using less material, leading to savings on transportation costs.

Foods commonly stored in plastic containers

In general, foods that are usually packaged in plastic containers are: