Food can spoil for a variety of reasons, but one of the main causes is the growth of microbes such as bacteria, yeast and mold that feed and grow on the food product, causing the food to go bad and rendering it unsafe for consumption. One way that we rid food of these pesky bacteria in our own homes is by cooking the food. But for pre-packaged, ready-to-eat and shelf-stable products, how can manufacturers prevent microbial regrowth and ensure long-term food safety?
For shelf-stable applications, extending product shelf life requires a strategic combination of retort processing, packaging material sterilization, and customized barrier material structures. These structures must deliver enhanced moisture and oxygen barrier protection while also supporting brand differentiation and performance requirements.
One example of a food packaging and processing method used to extend the shelf-life of food products is retort processing. Packaging developed for use in retort processing requires the use of sophisticated barrier materials to maintain product quality and meet shelf-life expectations. In addition, the rigorous conditions of the retort process present unique challenges, such as the risk of "retort shock," requiring additional material considerations.
Continue reading to learn how retort processing works, common packaging challenges, and how ICPG’s material solutions are engineered to perform in demanding retort applications.
What Is Retort Processing?
Retort sterilization and processing is the process in which a non-sterile food product, either raw or cooked, is filled into hermetically-sealed, non-sterile packaging. The packaging is then loaded into a retort pressure vessel and heated to extremely high temperatures ranging from 230-275° F for several minutes under high pressure.
Through this process, both the food product and the packaging are sterilized, resulting in commercially sterile, shelf-stable food products that are safe for consumption. Retort processing can extend shelf life from 16 to 24 months, depending on formulation, packaging structure, storage, and supply chain conditions.
A key benefit of retort processing is its cost-effective ability to safely process and sterilize complex food products. Compared to other preservation methods, retort processing enables large particulate foods, such as fruits, vegetables, and proteins, to be effectively sterilized within barrier plastic containers while achieving long-term shelf-life performance.
While retort packaging has traditionally relied on metal cans, advancements in rigid barrier plastic containers now allow for enhanced package shapes, lighter weight formats, and end-use features such as microwavable, ready-to-heat, and ready-to-eat meals.
Common Applications for Retort Products
Retort processing is commonly used across a wide range of food and pet food applications, including:In addition to the retort sterilization process, choosing a material structure that provides a combination of oxygen and moisture barrier protection also helps to extend the shelf life and reduce food spoilage and waste.
Managing Retort Shock Through Advanced Barrier Structures
Developing a rollstock structure that can meet key barrier requirements while reducing the risk of "retort shock" is essential for reliable packaging performance in retort processing applications.
Retort shock occurs when moisture permeates the material used on the outer layer of the rollstock, and reaches the encapsulated EVOH layer. When exposed to moisture, EVOH loses its oxygen barrier properties, reducing its ability to protect the sealed food product from oxygen permeation. Over time, this can lead to food spoilage, product waste, and financial loss for producers.
Managing retort shock through engineered multi-layer barrier structures is a critical factor in successful retort packaging design.
ICPG Material Solutions for Retort Processing
ICPG offers material solutions designed to support retort processing and packaging requirements, with structures that can be tailored to help achieve extended shelf life and consistent barrier performance. Multi-layer coextruded barrier rollstock structures are commonly used in retort applications to balance process durability, moisture resistance, and oxygen barrier protection.
Polypropylene-based materials are frequently selected for retort processing due to their ability to withstand high temperatures and resist moisture exposure during sterilization. In applications that incorporate oxygen-barrier layers such as EVOH, overall structure design plays a critical role in protecting barrier performance throughout the retort cycle.
ICPG supports retort packaging applications with symmetrical and asymmetrical multi-layer barrier structures that can be configured using polypropylene and EVOH to help manage moisture exposure and reduce the risk of retort shock, depending on application requirements.
To further enhance moisture protection, ICPG’s XPP Enhanced Barrier Polypropylene is engineered to improve moisture resistance compared to standard polypropylene materials, helping protect oxygen-sensitive barrier layers during retort processing.
Ready to Optimize Your Retort Processing Packaging?
Ready to get started developing a customized and enhanced material structure for your retort processing application? Download our XPP™ Enhanced Barrier Polypropylene product sheet today to learn how ICPG’s barrier solutions can support your packaging performance goals, or reach out to our team to discuss your packaging application.
