Retort Systems for Food & Beverages

First Published: May 1, 2024
Channel: Technology

What is a Retort System?

A retort system is thermal processing equipment used in the food and beverage industry to sterilize packaged products. It involves subjecting the sealed and packaged food or beverage to intense heat and pressure, typically through saturated steam or water immersion. It effectively cooks or sterilizes the contents to kill harmful microorganisms and extend the product’s shelf life, making our food safer.

What’s the Difference Between Retort and Aseptic Packaging?

Retort processing is often compared to aseptic packaging. How are they different? Here’s what the USDA says:

In retort packaging, food is filled into a pouch or metal can, sealed, and then heated to extremely high temperatures, rendering the product commercially sterile. In aseptic packaging, the food or beverage is sterilized by quick exposure to ultra-high heat, rapidly cooled to an ambient temperature, and filled into sterilized containers that are then sealed in a commercially sterile environment. However, the assembled aseptic package is not further processed like retort products.


How Retort Systems Work

Retorts come in many sizes and configurations, ranging from small systems for use in development labs to large-size machines designed to handle high-volume production.

Like a certain deep-diving submersible (which they often resemble), retorts have to withstand high pressures but are designed and built to much higher standards.

Retort System from JBT FoodTech

The basic process of retort systems involves the following steps:

Packaging: The food or beverage product is first filled and sealed into the desired packaging material, which can be flexible pouches, cans, bottles, or other suitable containers.

Once this part of the process is complete, the products move to the infeed of the retort system.

Loading: The sealed packages are loaded into a retort vessel, a pressure-resistant chamber designed to withstand high temperatures and pressures.

The packages are first loaded into trays that, when full, are transferred into the body of the retort system.

Heating and Pressurizing: Once the retort vessel is loaded, it is sealed, and the heating process begins. Saturated steam or water is introduced into the vessel, raising the temperature and pressure to the desired levels. The exact temperature and pressure depend on the product being processed and the desired level of sterilization.

This part of the process, as well as holding and cooling, is controlled by validated software that ensures each package in the machine is treated correctly to ensure consistent results.

Holding: The retort vessel maintains the high temperature and pressure for a specific period, known as the holding time. This holding time ensures that the entire product is exposed to the required heat and pressure for a sufficient duration to achieve commercial sterility.

Cooling: After the holding time is completed, the vessel is cooled rapidly, either through water cooling or air cooling, to bring the temperature down to a safe level for handling.

Unloading: Once cooled, the retort vessel is opened, and the sterilized packages are unloaded for further processing, such as labeling, packaging, or distribution.

This video of a rotary steam retort shows the process:

Animation Showing the Retort Process – from Allpax

    What Types of Packages & Packages Use a Retort Process?

    Traditionally, retorts were extensively used for food products packed in metal cans, but the process is very successful for bottles, jars and pouches as well.

    The list of products packaged using a retort process include:

    • Meat and fish products
    • Pet products, including treats and wet food
    • Juice and yogurt drinks
    • Coffee drinks
    • Ready to serve dinner entree selection
    • Soups, rice, sauces, pre-cooked vegetables and more

    Final Thoughts

      Retort systems play a crucial role in ensuring food safety and extending the shelf life of packaged products, particularly those in flexible packaging formats. They enable manufacturers to offer convenient, shelf-stable products while maintaining high quality and minimizing the risk of spoilage or contamination.

      They are an important part of food production and safety.

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