In this process, the food item is packed into a sterile container under sterile conditions and sealed in a way that microbial contamination is prevented. The food products that undergo aseptic processing are shelf-stable and have a longer shelf life. Non-sterile foods such as fermented dairy products like yoghurt and buttermilk are also packed aseptically to prevent any further microbial contamination.
The Aseptic Packaging Process
- a) Sterilisation of the food product before it is filled in the packet
- b) Sterilisation of packaging material or container and closure before it is filled with the food product
- c) Sterilisation of equipment involved in food processing
- d) Maintenance of sterility in whole manufacturing system
- e) Production of sterile packages
Types of Packaging Material for aseptic foods
Aseptic foodds are available in carton boxes (with or without the sin caps), three-sided pouches, glass bottles, glass jars and metal cans.
Conventional Canning vs Aseptic Canning
One of the most satisfactory methods of preserving foods for long periods is the process of canning, in which the food is sealed into a container and then sterilised by heat. Modern canning lines are capable of handling up to 2000 cans per minute, but the geometry of the can and the low thermal conductivity of food place constraints on the maximum heating temperature and type of food that can be canned. ‘Aseptic’ canning processes overcome these constraints by sterilising food in specially designed heat exchangers before it is filled into sterile cans. Such processes allow high sterilising temperatures to be used, resulting in improved product quality.
Canning requires packaging materials that can withstand high temperatures – metal containers, for instance. This makes canning an expensive processing method. Compared to canning, aseptic food processing requires less energy. Also, aseptic foods are convenient to carry because of their light weight.
Examples of Common Canned and Aseptic Food Available in the Indian Market
Tomato puree, coconut paste, buttermilk (mattha), lassi, fresh cream, flavoured milk (elaichi milk, chocolate milk, rose milk, vanilla milk, etc.), soy milk, milk packs (Tetra-Pak milk), fruit juices, savouries such as gulab jamun and rasgulla, canned fruits soaked in sugar syrup, and ready-to-eat savouries such as navratan korma.
Things to keep in mind while purchasing these foods
Do not purchase a leaking or puffed can or a torn Tetra-Pak. A puffed can indicates possible contamination and consumption of that product can lead to food poisoning.
Always check the expiry dates. A product that has expired is unfit for human consumption.
Usage and storage
- Store in such a manner that they are not damaged physically. Any tear can lead to microbial contamination. Discard any can or pack that is puffed or leaking.
- Before they are opened, most canned or aseptic foods can be stored at room temperature. Some products should be consumed immediately after opening. Some must be refrigerated after opening. The duration for safe consumption after opening the pack is clearly mentioned on the pack.
- Always refer to the instructions given on the food label. There are clear instructions about handling of the food, such as heating methods, duration for which it is to be heated, and any other precautions that one must take while handling the product. The label clearly declares that the product must be consumed within certain days after they are opened.
- If you stock aseptic or canned foods, consume the product that is about to expire earlier.
- Before consumption, carefully check the product. Discard a product that has an off odour, unusual appearance, or aftertaste.