Retort technology is around 200 years old. It involves the use of pressurized high temperature, steam or air. Nicholas Appert started the first commercial canning operations using Retort Technology. Can openers were invented 100 years later though now better alternatives are available.
Retort sterilization involves heating the product above 100 degrees celsius(121 to be more precise). The holding time for each product varies depending on itspH, microbial load, heat sensitivity, the type of packing, the efficiency of heat penetration as well as the efficiency of the retort.
There are 3 basic steps involved in the retorting process.
1. Product preparation – recipe designing has to be done taking into consideration the exposure to excess
heat over a length of time.
2. Filling & Sealing – the speed of sealing has to be so adjusted that filling is done and the batch
load is ready when the earlier batch comes out.
3. Heating, Holding and Cooling under counter pressure inside the Retort.
Counter pressure plays a very important part during the Retort Process as it could lead to opening/bursting of the packaging material or seal. Alternatively, it could cause collapsing of packaging rigid containers in case of the counter pressure being higher than the pressure inside the container.
Some time back there was only one type of Retort available in the market – Steam and Air Retort. Technology with help of research has made tremendous strides and we have a number of variations available in the Retorts. In addition to the Steam and Air Retort, we now have Water Cascade Retort, Water Spray Retort, and Water Immersion Retort to choose from. In addition, most of them can also have the option of agitation or rotation. Computerisation has led to PLC systems which help maintain the process conditions automatically.
For some time only Retortable pouches were available for packaging. Now we have a wide variety of rigid containers available for more attractive packaging.
Products like Mutton Biryani, Vegetable Khorma and a wide range of Ready to Eat and Ready to Cook range of products are now beginning to appear on the market using this technology.