Packaging Innovation
food processing methods and packaging materials
April 10, 2017

Food packaging design: how to comply with food processing methods?

Food packaging, evidently, needs to be as safe as it is appealing. Food processing methods greatly determine packaging requirements and, hence, food packaging designs. This article provides an overview of the packaging implications of the most common food processing methods.

Retort sterilization

Retort sterilization, or retorting, is a food processing method originally developed by NASA. The food is vacuum-sealed in a pouch or metal can (referred to as a retort) and then heated to extremely high temperatures to sterilize it. Retorting ensures the food retains its natural flavor and freshness for many months or even years (even without refrigeration). As the food is packaged before it is retorted, packaging materials must be able to resist high temperatures as well as mild pressure. Suitable options include glass containers, plastic or metallized pouches, and metal or plastic cans and trays.

Aseptic food processing

Aseptic processing briefly exposes food products to ultra-high heat, after which they are instantly cooled to an ambient temperature. Next, the food is placed in sterilized packaging which is then sealed in a sterile environment. Since the packaging must be constructed and sterilized on-site, most manufacturers opt for rectangular cartons because they take up less storage space compared to bottles and other types of rigid containers.

Microwave-assisted thermal sterilization

A new approach to retort sterilization, microwave-assisted thermal sterilization shortly immerses packaged food in pressurized hot water which is heated by microwaves and then rapidly cooled down. Compared to retorting, this type of food procession is known to better preserve flavour, texture, colour and nutrients. Packaging materials suitable for this type of food processing method are high-barrier plastic pouches and trays that are microwave-resistant.

Ultra-high-pressure processing

In the case of ultra-high-pressure processing, packaged foods are placed in a high-pressure container which is typically filled with water. The container is pressurized to 145,023 pounds per square inch (almost double the pressure at the deepest point in the ocean) for about five minutes. As foods containing moisture temporarily shrink up to 20 percent under this kind of pressure, the packaging materials used have to accommodate this. Flexible packaging is a must in this case, while rigid packaging is a no-go.

High-intensity light pulse processing

A non-thermal food processing method, high-intensity light pulse processing inactivates microorganisms on the surfaces of foods (and packaging materials) with pulses of UV light. If packaged foods are to be treated with this method, the packaging material must be transparent to allow UV light to pervade.   Inspired by Packaging Digest