Pasteurisation - sterilisation - jam, chutney, marmalade
pasteurisation - sterilisation - a confusing process in jam, chutney, marmalade.
I run a small jam factory, 3 things have always confused me in what in essence should be a simple process, these three things are down to interpretation.
firstly - jar treatment - most factory's invert jars picked straight from the pallet and fill. Others do all kind of things like hot water baths, jar cleaning lines, heating jars to x temp. I cannot understand why the process varies so much. If 'one' phones the tech team of a major glass manufacturer they will tell you the jars are sterile and sealed in heat shrink. Assuming heat shrink is in tact the jars will still be sterile?
secondly - pasteurisation - my understanding of pasteurisation is heating and cooling a liquid, above a certain temp for a certain time. - is this not done as a by product by boiling a jam to 105 degrees, then filling above 85 degrees creating a vacuum?
Thirdly - sterilisation - a process I have only seen done in one or two places where finished products are submerged in boiling water to achieve an internal temp of 85 degrees - surely if you fill at 85 degrees this process is pointless!!
all thoughts appreciated.
Hello,
That's interesting, all these differences. There may be overkill indeed (which may cost a lot of money if all this heat is lost somewhere). Without knowing the exact context, the products, the situation and history, the shelf-life and if the product is exported to tropical countries, it isn't possible to judge whether there is room for improvement.
However, let's have a deeper look in the process.
The heating has 2 objectives:
- Cooking the jam, marmelade and chutney to give it the desired structure and properties
- Kill a sufficient amount of yeasts, germs and molds and inactivate enzymes, to ensure that the product remains stable during the shelf-life
- For the chutney you need to take a closer look to the ingredients (for the eventual presence, survival and development of heat resistent bacteria)
It looks like the other heating steps you described are to avoid that a post-contamination may lead to spoiled products during the shelf-life.
Pasteurisation = Heat step at "low" temperature-ranges
Sterilisation = Heat step at high temperature-ranges (the step you indicated looks like a "factory term", because it doesn't have a sterilisation effect = A sterile product)
I hope this gives you some more information about the jam process. As said, more profound studies may lead to more energetically interesting processes and to better products, as heating causes lost of taste and colour.
Kind regards,
Gerard Heerkens
The problem with jam/jelly et all is that you have to prove your heat treatment is sufficient to render the botulism spores inactive (assuming your shelf stable). In Canada, we require a scheduled process by a competent authority that needs to be followed.
The heat treatment after fill is to create the required vacuum to prevent any air from penetrating the seal.
This link should assist
The problem with jam/jelly et all is that you have to prove your heat treatment is sufficient to render the botulism spores inactive (assuming your shelf stable). In Canada, we require a scheduled process by a competent authority that needs to be followed.
The heat treatment after fill is to create the required vacuum to prevent any air from penetrating the seal.
This link should assist
Interesting, so my thoughts on this are; we achieve a vacuum seal without the need for heat treatment after fill.
Can you not create a vacuum without heat treatment afterfill??
As long as you're certain your sugar content is high enough to preserve the jam and you've left just enough headspace you should be ok..but please please please check you're countries regulations
As long as you're certain your sugar content is high enough to preserve the jam and you've left just enough headspace you should be ok..but please please please check you're countries regulations
couple of videos from larger jam factorys, both clean jars after filling but neither pasteurise or sterilize.
sugar content always above 65g, we use rsb lids so we know the vacuum has been created. do you have rsb lids in Canada?
Sure do, that's what we use, but we're an acidified low acid food so a wee bit different