This is a video published by Tetra Pak, that describes research they undertook to establish whether the standard fruit juice pasteurisation conditions could be reduced to save energy while still guaranteeing shelflife and avoiding product “damage”.
They found that, for orange juice, the second pasteurisation could be reduced from 95C for 15 seconds to 80C. This reduces cost of energy for orange juice filling at 22 000 l/h over 500 shifts a year by 19% and carbon footprint by 20%.
They also found that the across plate temperature difference could be increased from 5 to 20C. This would have significant impact on the heat transfer surface required and hence the capital cost of the pasteuriser.
I was amazed to find this technical note on Tetrapak’s website.
click the image to open the note
Since I first heard of Tetrapak in the 1970s I always saw them as highly technology and science focused and the leaders in liquid food processing. I and many others accepted their process design parameters without question. Now after all these years Tetrapak has the foresight and courage to question whether what has become normal practice is really the best solution.
They apparently asked three questions can the heat load in pre-filling pasteurisation be decreased, will a lower pasteurisation temperature result in product change and can a larger design temperature difference be used.
This interesting paper seems to answer positively in all respects and reports a 1.3 kg per 1000l carbon footprint saving which indicated we will be seeing changes in our plants.
The paper first defines the need for pasteurisation as being to protect public health and to manage the selflife of dairy products.
It then defines pasteurisation conditions and describes the processes and equipment required to run pasteurisation in a dairy. Heat recovery, pressure drops, holding tube design and instrumentation are discussed in some detail.
As mentioned in a previous post the University of Guelph has a strong reputation in Food Technology and has some very useful online information. Its worth following the link from the image and browsing around to see what other useful information you can find.
This simple 3 page website discusses and explains the destruction of micro organisms by heat. This process is the basis of heat based pasteurisation and sterilisation unit operations in the Food Industry.
This isn’t an in depth paper but focusses on the death curve, D values and Z values, how these are used to define parteurisation conditions and how its slope relative to other inactivation curves justifies the high temperature short time process.
Guelph University has a strong reputation in Food Technology and has some very useful online information. Its worth following the link from the image and browsing around to see what other useful information you can find.
Reputable equipment manufacturers, especially the multi national ones are repositories of the state of the art process and equipment technology in the areas in which the work. This information is available to their customers during the installation of plant and is sometimes published and available to the public.
A case in point is the APV White Paper on Long Life Dairy, Food and Beverage Products.
The white paper covers a wide range of information both from a theoretical, process and equipment viewpoint.
The outline below indicates the content of the paper but not the content which is broad including for instance 6 other process technologies with the tubular steriliser described above. While the information is of course in line with APV’s processes and equipment, it still gives a good overview of the Long Life Dairy sector.
Introduction to long life dairy, food and beverage products
Choosing the right process
Various aseptic UHT systems
The Pure-Lac process
Comparison between different systems
This is really worthwhile information and APV should be credited with sharing it.
An October report by The French national food conservation research centre (CTCPA) stated that the process of “rapidly shaking packaged food products during sterilization reduces the processing time significantly and improves the colour, flavour, texture and ‘mouth feel’ of the food.” This was a result of being able to reduce the sterilisation cycle time by up to seven times.
Zinetec, the suppliers of the technology, say that the technology can be used with many canned, pouched and bottled food products and is suitable for thicker products, including those with larger solids. These include soups, sauces, ready meals, spreads, dips beverages, chopped vegetables and baby foods.
The capital costs is similar to conventional retorts but that the technology brings the kind of advantages to bottled foods that UHT brought to liquid foods.