For years, the packaging industry has worked hard to enhance preservation processes so that we can improve food quality and safety. Particular headway has been made in the field of commercial sterilisation of food.
Nonetheless, retort processing is not suitable for use with all types of packaging and it is important to have a good understanding of exactly what food sterilisation consists of and the packaging materials that can benefit from this process.
WHAT IS COMMERCIAL STERILISATION OF FOOD?
Commercial sterilisation of food is a process in which packaged and sealed foods undergo heat treatment at a very high temperature (between 115 and 127ºC) for a set time.
WHAT DO WE AIM TO ACHIEVE BY STERILISING FOOD?
The aim of the sterilisation process is to eliminate or decrease the number of microorganisms and spores around the product and, by doing so, diminish the risk of toxins developing through fermentation. This extends the shelf life of packaged foods. In addition, sterilisation works such that is does not alter any of the organoleptic or nutritional properties of food, which means it is entirely safe to use.
Examples of colonies of bacteria that can decrease the commercial sterilisation process of food include Clostridium botulinum, which causes botulism in humans. As a rule, bacteria of this kind can be eliminated through heat treatment at between 70 and 90ºC although most processes tend to reach over 100ºC. In addition to significantly decreasing food waste, this process gives us a food safety guarantee and eliminates dangerous pathogens.
IS THIS PROCESS SUITABLE FOR ALL TYPES OF FOOD?
While we can use commercial sterilisation with a wide variety of cooked foods, including meat, seafood and vegetables, and even more elaborate dishes, such as soups and sauces, characteristics such as the length and width of the product have an impact on the process.
One of the key factors, however, is the acidity level of the product. We can get this information from the pH which, for most foods, tends to be somewhere between 3 and 7. The lower the number, the higher the acidity of the product.
We sterilise foods with a neutral pH (above 4.5) at temperatures in excess of 100ºC and we use temperatures under 100ºC for more acidic foods. Microorganisms find it more difficult to reproduce in acidic foods and, furthermore, these foods do not respond so well to heat treatment.
COMMERCIAL STERILISATION FOR FOOD DOES NOT WORK WITH ALL TYPES OF PACKAGING
If we take the characteristics of commercial sterilisation for food and the temperatures it reaches into account, evidently it is not suitable for all types of packaging. There are several factors we need to consider if we want to use retort processing. The packaging material needs to meet certain criteria in terms of permeability and shape. This is the only means we have of guaranteeing product quality and shelf life and avoiding posterior oxidation.
FOODS THAT ARE SUITABLE FOR COMMERCIAL STERILISATION
There are several materials that are suitable for commercial sterilisation of food, including:
This recyclable polypropylene-based material with high-barrier properties works great as the top film on vacuum packaging that needs to go through retort processing. The PP HB ECOTOP top film is also compatible with rigid thermoformable trays made from polypropylene. This gives us a mono-material top film solution that can be recycled. It is perfect for products that tend to be packaged in MAP packaging rather than vacuum packed. It was also designed specifically to meet European Union sustainability guidelines and is a fine example of a material that can help boost circular economies.
As in the example provided above, this thermoformable material for vacuum packaging base webs is made using polypropylene and is another great example of how high-barrier properties and sustainability can go hand-in-hand in a material that can withstand retort processing. It can be used with the PP HB ECOTOP top film.
This recyclable material with high-level barrier properties can be used as an alternative to packaging that is not suitable for recycling and contains aluminium film, metal coverings or multi-material structures. It is ideal for stand-up formats.
These materials, designed specifically to improve recyclability, are just a few examples of the progress we have made in the packaging industry to date in order to reach optimum quality and food safety standards. We have delivered solutions that extend the shelf life of products while continuing to sustain safety guarantees and doing our bit to fight food waste. In addition, these materials help to make the entire logistic chain much more sustainable.
At SP Group, we champion innovation in the packaging industry and work hard to bring more efficient and sustainable solutions onto the market.