[HN Gopher] Microbiologist Investigates After Her Beef Soup Turn...
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Microbiologist Investigates After Her Beef Soup Turned Blue in the
Fridge
Author : notamy
Score : 50 points
Date : 2023-03-10 19:24 UTC (3 hours ago)
(HTM) web link (www.iflscience.com)
(TXT) w3m dump (www.iflscience.com)
| e40 wrote:
| The Hibiscus tea I use turns blue when I steep it at my mom's
| place, but not at mine. I have a very good water filter, she does
| not. First time it happened, I was quite startled. She had a
| filter at her place she never used, so we tried it. Yep, filtered
| water resulted in pinkish tea.
|
| What's in the water is unclear, but there was a lingering unease
| related to it.
| treeman79 wrote:
| There are lots of people that love to mock those that prefer
| bottled water. https://xkcd.com/1599/
|
| I've lived in lots of areas were the water burned going down.
| One place were water was just brown. Filtered leaves it weirdly
| bland. But acceptable for coffee / tea.
| hoseja wrote:
| That might be iron actually, somehow. I once cut a banana with
| a carbon steel machette and it turned blue.
| quesera wrote:
| I remember a grade school science experiment where something
| about moisture or humidity caused a color change from blue to
| pink (or vice versa?).
|
| I think the important bit was cobalt chloride. Doesn't sound
| like an ingredient in hibiscus tea though!
| raverbashing wrote:
| The water in your mom's place is probably a bit acidic if I had
| to guess, and the filter removes the ions
| gweinberg wrote:
| Shouldn't it turn red if it's acidic and blue if it's basic?
| pflanze wrote:
| Yes.
|
| Also, it is my understanding that calcium in water (which
| is a normal part due to the water taking up minerals in the
| ground) is making it slightly basic. I don't know enough
| about chemistry in this area, but I think the calcium in
| the water is mostly calcium carbonate, which definitely is
| basic[1]. So it's no surprise that water taken directly
| from the tap is making the tea blue, but after removing the
| calcium carbonate (maybe as part of a removal of any salts)
| that the tea remains red. I think this hints that an ion
| exchanger[2] is being used in the "very good water filter"
| e40 is using.
|
| But removing calcium from water (along with other
| potentially beneficial minerals) is a bad idea, because we
| need it for building our bones etc. Hopefully those using
| ion exchanger are still getting enough calcium from other
| sources. But it's long been said that ion exchangers should
| not be used to "filter" water.
|
| [1] https://en.wikipedia.org/wiki/Calcium_carbonate [2]
| https://en.wikipedia.org/wiki/Ion_exchanger
|
| PS. you can put some drops of lemon juice into your tea and
| it will shine red :) (and have a nicer taste)
| lightedman wrote:
| Hibiscus is a litmus indicator. Blue means your water is basic.
| That specific thing is how I make blue hibiscus pancakes.
| rubatuga wrote:
| You can also use red cabbage water
| cma wrote:
| Wikihow: How to Make an Indicator for Acids and Bases Using
| Hibiscus Petals
|
| https://www.wikihow.com/Make-an-Indicator-Using-Hibiscus-
| Pet...
| askvictor wrote:
| Many flower petals can be made into a pH indicator.
| zabzonk wrote:
| > If it turns out that the pigment is caused by P. aeruginosa,
| they would have to stop working on the blue soup due to its
| infectious nature.
|
| microbiologists work with much more dangerous organisms than
| pseudomonas all the time. speaking as an ex microbiologist.
| twawaaay wrote:
| Not a migrobiologist, but I understand that labs are equipped
| with progressively more stringent procedures depending on the
| type of material they can handle.
|
| They may work in a very regular, run of the mill lab that is
| not equipped to deal with anything that is even remotely
| dangerous.
|
| And seeing they have only nitrile gloves for protection and
| everything lays on the table it looks like this is likely the
| case. (Not that I ever worked in a lab. My ideas of how lab
| safety works are based on The Andromeda Strain).
| zabzonk wrote:
| pseudomonas is a very common urinary tract infection, along
| with e.coli and proteus, none of which commonly cause deaths.
| it is not particularly dangerous. using common sense and
| basic aseptic technique will keep you safe.
|
| back when (early to late 70s) we did not use gloves at all,
| because they were uncomfortable - just washed our hands a
| lot. nobody ever died or got infected. before i joined,
| someone did die from the hepatitis virus. we were not a
| virology lab, but we did do immunology, which is where the
| blood that caused the death came from - we did use gloves
| when dealing with that.
|
| for the more dangerous organisms, such as mycobacterium
| tuberculosis, we used air extraction hoods.
| twic wrote:
| Yes, but they won't have done a risk assessment for it. As you
| will know, microbiologists are supposed to have risk
| assessments for precisely what they're doing; as you will also
| know, they are often pretty approximate about it; but in the
| case of work documented in a virally popular Twitter thread, it
| would probably be sensible to be seen following the rules.
| kazinator wrote:
| "Don't it make my brown eyes^H^H^H^Hsoup blue."
| dvh wrote:
| Few years ago there was a case in my country where store bought
| ham/sausage glowed in the dark:
|
| https://youtu.be/WgsBF9jzDEw
| lovich wrote:
| Was there garlic in the soup? Garlic can turn green or blue when
| cooking depending on the ingredients involved. I assume the
| bright blue photo in the article isn't an actual picture of the
| soup in question.
| sp332 wrote:
| https://mobile.twitter.com/bielleogy/status/1630811835527213...
| dhosek wrote:
| There was no garlic in the soup. There are links to the twitter
| thread although most of the interesting tweets are shown in the
| article as well.
| pimlottc wrote:
| It really peeves me how often articles use unrelated stock
| photos for their hero image, often without even noting it.
| messe wrote:
| There's an actual picture in an embedded tweet further along
| the article.
| Maursault wrote:
| My stomach turned at "meat soup." What is that?
| Oh, you don't want to hear about that. They lined us up in front
| of a hundred yards of prime rib. All of us, you know, lined up
| lookin' at it. Magnificent meat, really! Beautifully marbled.
| Magnific. Next thing, they're throwin' the meat into these big
| cauldrons. All of it! Boiling it! I looked inside, man, it was
| turning grey.
| smcl wrote:
| Soup with beef in it is relatively common in the two places
| I've lived - UK and Czech Republic. Couple of very normal
| examples of "beef soup":
|
| https://www.bbcgoodfood.com/recipes/oxtail-soup
|
| https://www.daringgourmet.com/traditional-scotch-broth/
|
| https://www.angusfarm.cz/recepty/hovezi-vyvar-698/
|
| http://www.pradobroty.cz/2019/03/gulasova-polevka.html
|
| I think what the _saucier_ in your quote[0] was upset about was
| cooking good quality meat very badly, not the idea that meat
| generally could be used in soup :)
|
| [0] - for those who don't know, it's this scene:
| https://www.youtube.com/watch?v=YbFvAaO9j8M
| wazoox wrote:
| Once in 1991 I left some cooked rice in a pot in the kitchen. The
| next day, it was covered with a bright violet slime. I don't know
| what it was, but I still remember it vividly (as the colour was).
| Scoundreller wrote:
| Possibly b. cereus
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