Naked Science Forum
General Science => General Science => Topic started by: vhfpmr on 11/05/2020 15:47:29
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If cheese is left to mature for months, why does the packet say use within 3 days of opening? After all, cheese was invented as a means of preserving food.
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Surface to volume ratio, and infection.
Cheese is produced in large blocks, either sterile or infected with specific bacteria that produce a local flavour. The blocks are covered with a protective wax rind or salt, so everything that happens inside is controlled and predictable.
When the block is cut for retail, this highly nutritious material is exposed to oxygen and all the bugs and yeasts floating about in your kitchen, so what was once a slow maturing process is now a playground for anything and everything that eats cheese. Prepacked wedges are prepared in fairly sterile conditions so may last almost as long in your refrigerator as the original bulk cheese but as soon as you open the pack you are turning it into a potential can of worms.
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I would add: Freshly-cut cheese has a carefully-controlled moisture profile and texture.
Once the package is opened, it tends to dry out, go hard and discolor.
Fresh cheese has the carefully-honed texture intended by the producer.
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I would add: Freshly-cut cheese has a carefully-controlled moisture profile and texture.
Once the package is opened, it tends to dry out, go hard and discolor.
Fresh cheese has the carefully-honed texture intended by the producer.
A bit of cling film keeps it from drying out for a lot longer than the marked shelf life though. I could polish off a pack of cheese in one sitting, but when you're living alone and eating sensible portions it tends to stretch the use-by date a bit.
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cheese has a carefully-controlled moisture profile and texture.
The composition of fresh cheese is so tightly controlled that I used wedges of supermarket Gouda to test and calibrate mammographic x-ray machines, back in the day. It's all got a lot more sophisticated since, but the composition was very consistent and an adequately reproducible substitute for breast tissue.
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Gouda to test and calibrate mammographic x-ray machines
Hmmm...Using the product of bovine mammaries to calibrate human mammaries...
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cheese has a carefully-controlled moisture profile and texture.
The composition of fresh cheese is so tightly controlled that I used wedges of supermarket Gouda to test and calibrate mammographic x-ray machines, back in the day. It's all got a lot more sophisticated since, but the composition was very consistent and an adequately reproducible substitute for breast tissue.
What did you test the cheese against.
Did you have a reference breast?
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The objective was to ensure similar and predictable performance and safety between x-ray machines in the early days of the national breast screening program. No discernible structure but Gouda gave a reasonable approximation to the x-ray absorption and scatter and mechanical compressibility of breast tissue.
Various "reference breasts" were developed later, particularly at Leeds General Infirmary and under contract with the International Electrotechnical Commission, using polymethyl methacrylate as the matrix with various mineral grains and copper filters. The usual "demonstration breast" was a grapefruit: skin, water and various organic structures including a nipple, which looked radiographically like animal tissue but clearly isn't stable or reproducible.
Happiest recollection was when I had just signed off my first screening unit and the first patient walked in. She looked nervously at the compression paddles and said "Is this where I come in looking like me and walk out looking like you?" An alert radiographer said "Not quite. The chest is free but you have to pay extra for the moustache."
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If cheese is left to mature for months, why does the packet say use within 3 days of opening? After all, cheese was invented as a means of preserving food.
Because not all mould or maggots are equal.
https://en.m.wikipedia.org/wiki/Ergot
https://www.dailymail.co.uk/femail/article-2320397/The-germ-ridden-spot-kitchen-Refrigerator-WATER-DISPENSERS-harbor-concerning-levels-bacteria.html
https://en.m.wikipedia.org/wiki/Salmonella
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When the block is cut for retail, this highly nutritious material is exposed to oxygen and all the bugs and yeasts floating about in your kitchen, so what was once a slow maturing process is now a playground for anything and everything that eats cheese.
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Wow, look a plagiarist! Whether bot or human, I suspect dobolgatfr might not have anything to add to this thread...
In the off chance that dobolgatfr is a real person struggling to figure out how to use the "quote" functionality, I hope they do not take offense at my swift judgement. Future posts will help me to calibrate that judgement.
When the block is cut for retail, this highly nutritious material is exposed to oxygen and all the bugs and yeasts floating about in your kitchen, so what was once a slow maturing process is now a playground for anything and everything that eats cheese.
When the block is cut for retail, this highly nutritious material is exposed to oxygen and all the bugs and yeasts floating about in your kitchen, so what was once a slow maturing process is now a playground for anything and everything that eats cheese.