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:

5 steps to create your own preserved food business
5 steps to create your own preserved food business
Perforación del envase para insertar la sonda flexible corazón de las autoclaves TERRA Food-Tech

How to produce preserves and ready meals in plastic containers

Regardless of the type of container chosen, the first thing to do is to make sure that you have enough containers and that they are in perfect condition, without any type of damage.

Once your product is cooked, you can proceed to pack it. Given the variety of plastic containers available for marketing gourmet food and ready meals, you can use trays, bottles or pouches, and the task of filling the containers will vary slightly from one container to another.

When using trays, thanks to their wide opening, you will be able to add the preparation directly with a spoon. For bottles, employing a funnel is necessary, while for pouches, the requirement of a funnel or a dispenser depends on whether they are designed with spouts or not.

When using trays and pouches without spouts, you must fill the container completely and, in the case of containers with screw caps, you must leave an empty space at the top. Next, you will pasteurize or sterilize your product with an autoclave. After the heat treatment is complete and the containers have cooled down, the next step is to label them, a process that can be done either manually or through automation, depending on the scale of your production. The final stages involve storing and distributing the products. It’s important to note that if the products have been pasteurized, they must be stored in a cool environment.

When using bottles or pouches equipped with screw caps, it’s essential to leave some empty space at the top. This precaution prevents the contents from spilling out through the cap seams due to thermal expansion during processing, which could lead to product loss and contamination of the autoclave and other containers.

Autoclaves para centros formativos

Should you pasteurize or sterilize your canned foods and ready-made meals in plastic containers?

The container does not determine the heat treatment to be applied; what does is the food and the objective of the person who prepares it.

If what you want is a relatively fresh product, which needs to be refrigerated between 3ºC and 6ºC and with a maximum shelf life of 2 to 3 weeks, you should pasteurize it. Please keep in mind that some foods, due to their pH, must be pasteurized so that they do not lose most of their nutrients and organoleptic characteristics.

On the other hand, if you want your gourmet canned foods or ready-made meals to be at room temperature and have a shelf life of up to 5 years, sterilization is your option.

Alimentos en envases de plástico

Common problems related to sterilization in plastic containers

Regarding plastic containers with twist-off or screw-on lids, the particularity lies in the filling process. Due to this type of closure you cannot fill the container completely and you will have to leave an empty space between the food and the cap in order to achieve an airtight seal and allow the food to expand when heated without escaping through the cap joint.

If the plastic of our container is transparent, we must take into account that the small amount of oxygen that remains inside our canned food (vacuum packaging never reaches 100%), can darken the surface and affect your product. This is quite normal and not harmful, but it can be unsightly.

As for the bacteria or fungi that may proliferate in our gourmet canned food or ready-made meal, they have nothing to do with the container but with the food. Depending on whether the product is meat, fish, seafood, legumes, fruits or vegetables, some microorganisms will grow and a more or less aggressive treatment must be applied.

In order to prevent microorganisms from growing in your product once it has been pasteurized or sterilized, it is essential to ensure that the container is not damaged in any way, since one of the main functions of the container is to act as a barrier to the external environment. In other words, the container must stop the entry of external microorganisms. Therefore, it is recommended to check them before adding food, avoid impacts and store them in places protected from light, water and air currents.

Useful tips for the sterilization of food in plastic containers

To mitigate the potential darkening we mentioned earlier, consider drizzling some olive oil over your product before sealing and sterilizing it. Additionally, strategic label placement can help cover up some of what is not aesthetically appealing of the product, which, it’s important to note, are completely safe for consumption.

Here are a few natural and safe options to ensure your preserves are not affected by pasteurization or sterilization and still look good.

Counterpressure is critical in the sterilization process of flexible containers, acting as a protective mechanism against breakage or deformation under high-temperature conditions. In pasteurization, where the product doesn’t expand much, a lower counterpressure is needed. For procedures where the chamber probe regulates the temperature, our autoclaves offer the capability to gradually decrease chamber pressure across several stages or ramps, a benefit that is particularly useful for plastic containers.

How do TERRA Food-Tech® autoclaves enhance the sterilization process for your plastic containers?

The different characteristics of TERRA Food-Tech® autoclaves for sterilizing glass jars make a small equipment a great production partner that is cost-efficient, fast and versatile.

Adjustable F₀ - P₀

Pasteurizes or sterilizes accurately using F₀ and P₀ values

Fast cooling

Fast cooling by water shower to avoid overcooking the product

Adjustable counterpressure

Programmable counterpressure value according to the type of container

Traceability for audits

Manage and record the process from start to finish with our software

Precise control

Continuous process monitoring thanks to the flexible temperature probe

Protection

Excellent safety measures for the user and his products

Cálculo de la capacidad productiva

Are you looking to enhance the production efficiency of your preserves or prepared meals business?

At TERRA Food-Tech®, we assist you in assessing the productivity you can achieve with various models and types of containers.

The insights from these analyses prove invaluable when choosing the most appropriate autoclave model for your project.

Such evaluations remain beneficial even after acquiring an autoclave, as they enable us to understand how production capacity may vary with changes in container size.

Moreover, we design tailor-made baskets and racks to suit the specific requirements of your business.

Need some inspiration? Dive into the success stories of our customers who utilize plastic containers.

To discover more about our customers who have opted for plastic containers for their preserves, just go to our success stories section and take a look. Remember, each of these entrepreneurs worked hard to succeed with their gourmet food businesses. Would you like to become one of them?

Artisan preserves
Preparation of ready to use stir-fries and minced food products
Production of plant based energy pouches
Looking to learn more about the sterilization in plastic containers with TERRA Food-Tech® autoclaves? Contact our experts today

Explore additional articles on sterilization across various types of containers.

You have probably seen on the shelves of your supermarket a wide variety of preserves packaged in cans. In past times, cans were a great innovation that still persists today. In this article we will tell you the history of this metal container and then focus on its characteristics when it comes to pasteurizing or sterilizing them.
Are plastic containers the most suitable ones for my canned foods? Can this material resist the high temperatures involved in pasteurization and sterilization? All these questions will be answered in the following article.
The purpose of this article is to inform you about the special features of this plastic container with regard to the production and marketing of gourmet preserves and/or ready-made meals. Of course, we will focus on pasteurization and sterilization processes when using this type of container so that you can decide whether or not it is the right choice for your products.
In this article we want to let you know the pros and cons of choosing bottles as containers for your gourmet preserves or ready-made meals. In addition, we will focus on the pasteurization or sterilization of your product and which type of material, either glass or plastic, is more suitable for you.
In this section you will discover the particularities of pasteurizing or sterilizing any food packaged in a plastic tray, also known as punnets. You will also learn the pros and cons of packaging your product in this type of container.
The use of autoclaves for sterilizing food in glass jars has revolutionized the way we preserve food, guaranteeing both quality and longevity. These machines enable airtight sealing and thorough sterilization, catering to the diverse requirements of both the food industry and home canning practices.
Este es el elemento que se ocultará en pantallas de escritorio.