Ask MetaFilter questions tagged with bacteria

Proper culture for soy yoghourt

monocultured — Wed, 18 Nov 2009 04:35:18 -0800

Trying to make my own vegan soy yoghourt from scratch, I ended up with an uncultured mess. Please advise on proper microbial use, or improvements upon whatever else it was that I mucked up. I have a 1 litre yoghourt machine which plays a tinny "Macarena" when the 5-11 hour timer runs out, although I'm not certain of how exact the timer is. It does seem to keep the temperature constant at above room temperature though.

I made 2 litres soy milk — this I've done before since I occasionally make my own tofu — and let it cool. Mixed one litre into the machine with one sachet of the stuff in this picture and let it sit. After ten hours there was a 1cm gelatinous strata on top of the stuff, but below it was mostly curdled, like what you might expect if you mix soy milk with hot drinks.

The images below are after 24 hours. There's a slight tangy taste to the liquid, but it's nowhere near yoghourt levels of awesome, nor is there any texture except the grain you see. Looks like seperation, not a healthy process.

Texture 1 & 2
Separation 1 & 2

Possible stuff that has gone wrong:

1) Wrong kind of bacteria (intended for dairy?)
2) Contamination in the bucket (didn't wash it with boiling water)
3) Soy milk too watery or too thick

I'm in Sweden, so there's scant competition among the makers of soy products and I haven't found any starter kits to buy. The Alpro soy yoghourts are excellent, but I've read that they don't contain "live culture" so won't work as starters. Their yoghourt is what I ideally would end up with, so have that in mind, not the more gelatinous products out there.

What to use and where to get it would be appreciated — European stuff preferably — as well as any primers on the noble art of ennobleling the bean of soy by means of bacterium.

Germs on my hands

MrMulan — Mon, 16 Nov 2009 14:17:15 -0800

Is it possible for bacteria, and/or viruses to ever physically adapt to soap, alcohol, peroxide, iodine, ect.? Washing your hands is the best way to cut down on a known vector for germs to spread. Could bacteria adapt physically in a similar way lice or hookworms have? Or does their size make it impossible? Same for viruses.

I know bacteria can and are adapting to chemical solutions like anti-bacterial soap. When hand washing with soap, the soap is not suppose to kill the bacteria, but it is the physical activity of rubbing that gets rid of the bacteria. The soap just makes it physically easier to transfer bacteria from your hands to the soap which is then washed down the drain.

As for viruses, could they ever evolve to the point that the usual disinfectants would not work? (alcohol, lysol, ect.)

Personal answers, opinions, anecdotes, are all welcomed, but links are always preferred.

As always thanks in advanced.

Is there anything fishy here?

Taurid — Fri, 06 Nov 2009 21:57:53 -0800

Its that time of the year again, when I get the furnace cleaned, install a new filter, clean the humidifier ( and install a new humidifier pad), and start it all up. In the last few years, I've seen something called the "Swordfish" advertised. Its an ultraviolet light that is connected to the furnace ductwork and kill bacteria as well as mold that passes by the light. I've read some reviews about it and it sounds as though it does work. However I'm still a little skeptical. Does anybody have one or have any thoughts on it?

Everybody dies. How do they look?

kbanas — Mon, 12 Oct 2009 07:16:43 -0800

I'm toying with an idea for a short story or maybe a long story or maybe no story, but the idea has led me to a point where I have a question for those of you who have some knowledge about science and biology. Read on, brave adventurer! So, let's say I have a magic button, and I press that button and every single living thing on the planet dies instantly. I understand that the definition of what is "alive" is a subject of some debate for certain corner cases, but since I am not a scientist and I lack the knowledge necessary to carry on an informed debate on the topic, let's just assume that by "alive" I guess I mean that "it is a commonly held belief among people who study such things that this thing is alive."

So, I would think that this would include people, plants, animals, bacteria, and a laundry list of other things I'm not thinking about.

Ok, so we have our magic button and we know what it does.

Let's say I press that button and everything drops dead where it stands. Hooray!

Now, I know that when a person normally dies, there is a process of decay that works to erode the integrity of said corpse over time.

My question is, how would this process be altered by the lack of any other living things existing? It would be my assumption that this would largely apply to bacteria and things that maybe eat away at a body after it is no longer alive?

So, maybe to phrase it a better way....

Let's say I was able to magically visit this now-dead Earth some 20 or 30 years after I had pressed my magic button. If I encountered the body of a person who had dropped dead on the street in Anytown, USA, what is it likely to look like? I assume that perhaps the elements - sun, rain, snow, wind - might have served to work it down to a skeleton regardless of any other living factors. Right? Ok, but let's say a person dropped dead while being largely protected from the elements - like in a house or in an office or something. What is it likely to look like? Would the lack of bacteria and such work to preserve it such that it would look almost freshly dead? Or would it perhaps look mummified?

Maybe you get the idea. I want to visit a dead planet some decades after the "event" - and I'm curious about how I would find the people and animals and such to look. Get it?

Fecal Coliform question

Barmecide — Fri, 29 May 2009 08:39:22 -0800

Fecal coliform contamination. Not in bathrooms, or kitchens, or doorhandles, or workplaces, but on you. Related to a previous Mefi post which I've been unable to find. Recently there was a MeFi or AskMe post dealing with this, but I've been unable to find the comment (or cites!) dealing with it.

The gist of the comment was that despite anyone's best intentions, throughout the day they would become contaminated with fecal coliform bacteria (might have just been trace amounts, might not have.) This wasn't dealing with pickups from doorhandles or keyboards, but just, well, natural is the word I guess, contamination from going about one's day. The punchline was that no matter what you do, by then end of the day you skin is basically contaminated from waistline to mid-thigh. Can anyone help me find the comment/cite?

Help me fix my antibiotic-shredded stomach!

Anonymous — Mon, 06 Apr 2009 11:26:32 -0800

How do you fix a stomach blitzed by antibiotics? I just got out of the hospital, where I was on an IV drip of crazy strong antibiotics for three days (for a kidney infection). They also made me take a bunch of mineral supplements (magnesium and potassium mostly) that shred my stomach under the best of conditions. And while I was there, they didn't let me eat for almost 48 hours because they kept doing CAT scans to check the progress in my stupid kidneys.

So- I'm coming off of almost two days of a totally empty stomach, the good bacteria balance in my stomach is totally destroyed, and all the mineral supps have just added to the problem. Every time I try to eat my stomach just clenches up in pain that comes in waves and almost doubles me over.

I have talked to my doc about this and he said to take acidophilis pills, which I am, and I'm also guzzling yogurt. But it's been two days now and I've yet to see any improvement, and I'm freaking starving. Can anyone recommend any other OTC meds or supplements or foods that I can take to quickly rebuild my, for lack of a better word, ecosystem?

Thanks in advance!

How to identify science fair bacteria in agar nutrient gel

zeoslap — Thu, 02 Apr 2009 08:08:11 -0800

What kinds of bacteria make red and yellow spots in agar nutrient gel? So my Kindergartener recently did a science fair project where he made up some agar gel and then tested cleaning his hands with various things to see which worked best. All manner of things grew in there, and I'd like to know what exactly.

Some bits grew kinda black and moldy, other bits white and spidery, and then there were some very vivid small red and yellow dots.

Any idea which kind of bacteria produce these different growths?

I just ate accidentally ate some cheese with pink bacteria growing on it, will I get sick?

CTORourke — Mon, 23 Mar 2009 14:53:03 -0800

I ate some cheddar cheese with a pink bacterial plaque growing on it, could this be something that'll make me sick? I cut up some cheese for my lunch, some of it having been in my fridge for awhile. I was munching on the cheddar when I noticed it had a bit more smell than usual. I looked closely and saw some pink bacterial plaques growing on the surface.

I'm a biologist, but not a microbiologist, and I know that sometimes the e.coli and other crazy bacterias (we grow for the Introductory Biology lab I teach) can be pink. I also know that not all bacteria is toxic, not even all e.coli bacteria, but the fridge at my apartment has never been cleaned out properly and I know some weird stuff has been in there over the years.

Does anyone think it might be just an outgrowth of the normal lactic acid bacteria of the cheese? The bag the cheese was in was a little damp, which probably encouraged the growth. I threw the rest away.

If it is a bad bacteria, how long would it take for me to start getting sick?

Ugh. Make it stop!

missuswayne — Fri, 20 Mar 2009 11:05:47 -0800

How do I heal my gut? I have a history of IBS, and years ago I had an H. Pylori infection. After the infection was taken care of my gut was good for several years, no real issues to speak of. Since I had my kids a few years ago, my tummy's been on a bit of a rollercoaster, especially in the last year. Recurrent gas, terrible sharp pains an hour or two after eating, alternating diarrhea and constipation. Thought it was gluten (nope), dairy (nope), coffee (nope).

Coincidentally (or not?) I've been on antibiotics several times in the last 4 or 5 years, and I've had about 7 or 8 courses in just the last two years. I have severe allergies and have taken the antibiotics for recurrent sinus infections.

I now suspect that perhaps the antibiotics have obliterated the good bacteria in my gut. I eat yogurt (Stonyfield) most days, and I'm trying to increase my exercise (to get my intestines moving regularly and normally) but I'm looking for guidance as to what other things I can do to heal my gut from the antibiotic assault.

(I know you're not my dr, I've got an appt with a gastro coming up. Just looking to get a jump on things.)

Copper holy grail for embarrassing skin infections (and wrinkles, too)?

cybercoitus interruptus — Tue, 03 Mar 2009 15:36:31 -0800

Seeking info on the effectiveness of Cupron textiles, which are supposed to have wrinkle- and microbe- fighting properties due to being plated or impregnated with copper. Anybody have personal experiences with the pillowcases, bed sheets, towels, socks, etc, or can offer informed critiques of the company's studies? I saw the pillowcases at Bed Bath & Beyond yesterday and thought, "Sounds too good to be true, so I'll read up online before buying." I'm primarily interested in whether they really work against microbes because I'm having trouble getting rid of a chronic non-MRSA staph infection (yes, I'm doing everything my MD tells me, and have been for months, and tried alternative health approaches for good measure, all of which help but the lesions keep recurring).

I've read a couple of the articles by the company's personnel (scroll down to authors Borkow and Gabbay). "Biocidal textiles can help fight nosocomial infections" in Medical Hypotheses, and "Copper Oxide Impregnated Textiles with Potent Biocidal Activities" (proof only), from my lay perspective, seem sound (small pilot studies only, but still). I'd like to hear what people, who are used to evaluating science articles professionally, think of them.

(And if it really works on wrinkles, it'll make a great gift.)

Google turned up this hypothesis about the anti-wrinkle mechanism, this interview with Gabbay, and this article
that mentions a contrary opinion. Nothing about it on Quackwatch.

I will ask my dermatologist what he thinks, but since he flatly dismissed the idea that staph can be airborne or that it can be carried and transmitted by pets - well, ok, he didn't say it was impossible that I could have been colonized in these ways, but only highly unlikely. So unlikely as to be not worth considering in the arsenal I'm building of how to maximize my chances of getting rid of this, and minimize my chances of getting re-colonized from the same source (complicated backstory involving in-laws). Compared to what I've heard from my MD friends and read online, either his information's not up to date or he subscribes to a narrow view of how staph can be communicated. So I'm not going to rely on his opinion alone.

The germs crawl in, the germs crawl out...

Bardolph — Wed, 11 Feb 2009 09:44:47 -0800

Kid's due this spring, and we've amassed huge piles of used baby gear. What are some safe disinfecting procedures that will reliably rid all this stuff of any lurking mold, bacteria AND viruses? I'm not a germophobe or anything, and I understand and believe the hygiene hypothesis-- but with all the stuff in the news recently about what happens When Microbes Attack (black mold! obesity viruses!), I'd at least like the kiddie to start out with a blank slate, flora-wise, instead of Freecycle's Best premium microorganism assortment. Criteria for disinfection procedures: must be

ultimately baby-safe (so, not necessarily completely natural or nontoxic, but should be rinsable or removable to leave a safe end product)
as un-damaging as possible to the stuff itself (won't be easy with fabric cushioning/other mixed-material stuff, I know), and unlikely to break down plastics to yield toxic byproducts
effective against molds, bacteria, viruses, and (ideally) bacterial spores.

My current idea is to start by dousing everything with a mild bleach solution to clear the field, then follow up with Dr. Bronner's Tea Tree Soap and lots of baking in the sun to remove residual chlorine. I was also considering just using lots and lots of 95% ethanol, but wasn't sure whether it'd do much against viruses and molds. Would love to hear critiques and/or better suggestions for how to accomplish this!

How Would Mr. Wizard Make A Pitri Dish Lab?

peter_meta_kbd — Sun, 25 Jan 2009 10:37:13 -0800

What's the best way to do a pitri dish culture of a bacteria, to determine its positive/negative response to a variety of applied substances? Suppose that a person living in the third world wants to have a homemade pitri dish lab, to culture some bacterial infection. The goal would be to try out a variety of antibiotics, chinese folk medicines, herbs, juices, whatever, just to see how the bacteria responds to each one positive/negative. Can the pitri dish lab be made from stuff available in the supermarket? How can it be done? Whether or not the pitri dishes can be made or bought - how to do the experiments?

A clean pair of clothes...really?

abdulf — Mon, 29 Dec 2008 13:50:46 -0800

Is gym-provided workout clothing safe to wear? I'm trying out a fancy gym close to work that provides work out clothes in addition to towels and other amenities.

It sounds like a great concept. I would rather not carry a change of clothes and then have to handle wet sweaty clothes until I get home. But what are the risks?

The clothes come from a common pool, like towels, so you don't keep your own. Someone else may have worn the shirt or shorts the previous time.

They also provide jock straps, but that's touching a little too close for comfort.

The clothes look and smell clean but I'm concerned about things like skin diseases spreading to me and possibly some sort of STD.

I mean, people buy and wear used clothes from thrift stores after washing them. Is a wash cycle with hot water and soap enough to eliminate most of the risk?

I have little understanding of how hardy virus, bacteria, fungus, skin flakes really are. Please enlighten me.

Are these eggs safe to eat?

dubold — Fri, 10 Oct 2008 09:02:30 -0800

Should-I-Eat-This-Filter: I left a half-dozen eggs on the counter yesterday... They were uncooked, still in their shells, out of direct sunlight. I'd estimate the kitchen was about 70 degrees. They were there from 8am-7pm. When I came home and found them still out, I popped them back in the fridge. The eggs are from our CSA, so they're organic, free-range, etc.

I did a bit of research, and from what I understand, salmonella is only a risk if there's already salmonella bacteria in the egg. To be on the safe side, my pregnant wife won't be eating any of these. Are they okay for me to eat? What factors contribute to eggs going bad? is it time, temperature, or a combination? I understand that the safest course of action is just tossing them, but I hate to waste food.

you are not my doctor, nor will i hold the moderators responsible if i get sick. thanks.

Double-boil chicken stock?

nitor — Wed, 08 Oct 2008 17:23:39 -0800

Boiled some stock on Monday, stock sat out for 2 days. Can I salvage it? I bought a BBQ chicken on Monday night. After picking it to pieces, i threw the bones, skin, and whatever else was left in a pot with some hot water and boiled it to make stock. I forgot about it. Yesterday (tuesday) came and went, and it is still sitting on the stove. Today is Wednesday. If I boil it again for a bit of time, will it be ok to eat? Have I waited too long to salvage it?

Will my hand really turn skeletal?

sunshinesky — Sun, 28 Sep 2008 17:19:44 -0800

HouseholdChemicalsFilter: Due to a latex allergy, general hatred of inner-glove dampness, I prefer to clean the house without using gloves. Am I putting myself in any grave danger? Ok, so I haven't died yet from bacteria, or had the skin melt of my hands from corrosive cleaners, but I'd really like to know what I'm doing to my hands.

I use chemicals like Comet, lysol disinfectant, pinesol and more rarely a general purpose degreaser (nothing heavy duty).

Specifically I'd like to know if I'm splashing bacteria water all over my hands in a bucket of hot water/disinfectant or if I'm absorbing/melting my skin with the cleaners. I always wash my hands with antibacterial hand soap between chemical and anything else. Is that necessary?

(and yes, I know I can get non-latex gloves)

A bugs life?

greytape — Mon, 22 Sep 2008 06:42:20 -0800

Help me settle a bet about the total number of identified bacteria and viruses. Last week a friend, recalling a university lecture, said that the number of named and identified species of bacteria and viruses account for 98% of the total number of named species. I doubted this and thought it more likely that though there are fifty times as many species of bacteria and virus as there are any other kind of species, not all them have yet been named and catalogued. I suggested that this 98% figure is more of an estimate.
I base this supposition on the fact that it's so much easier to identify species that are visible to the naked eye and that people have had a lot longer to do it (the microscope being a relatively recent invention). Am I wrong?
Google has failed me, can Metafilter help?

P.S. As part of my searching I’ve been unable to find an estimate of the total number of identified species, and this has rather piqued my interest. Any help with this would be great too.

Thanks!

Looking for Bacteria

iconjack — Thu, 14 Aug 2008 13:52:07 -0800

Which strains of (harmless) bacteria are most susceptible to radiation? Looking for a good choice of bacteria for science fair experiments, where good means harmless, accessible and easily killed by radiation.

My rice cooker keeps infecting my rice!

rxrfrx — Wed, 23 Jul 2008 17:26:59 -0800

My Zojirushi rice cooker is contaminated with some kind of bacteria or mold. If I leave cooked rice in it for more than 24 hours, the rice goes mushy and stinky. This never happened with my $15 cooker. Help! I have a made-in-Japan Zojirushi rice cooker (NS-JCC10) that I bought used on Craigslist for $50. Good deal, right? It makes slightly better jasmine rice than my $15 cooker, and way better short grain rice.

Problem: I am used to cooking rice, scooping some out, and then closing the lid (with the cooker unplugged) and coming back over a period of a few days to get the rest of the rice. I've never had my rice spoil in the $15 cooker, which makes sense, because the cooking process sterilizes the inside of the unit with steam.

In the Zoji machine, the rice comes out fine, I scoop out some rice, close the lid, and come back the next day to find some absolutely foul mushy stuff. The rice becomes liquified and slightly blue over the course of a few days. This happens even if I scoop the rice with a spoon that I've sterilized by boiling.

I suspect that the steam vent unit is somehow allowing steam to condense on a cool, non-sterile surface and then drip back into the rice pot. I've pulled out the steam vent plug thingy and soaked that in rubbing alcohol, but there's a lot of space inside the lid that I can't reach (and it smells like the gross stuff that grows on my rice).

Is there some way to disassemble the whole lid and get in there? Has anyone had a similar problem? Thanks!

Probiotic tablets -- how can bacteria be dried?

humblepigeon — Wed, 11 Jun 2008 08:00:34 -0800

Probiotic vitamin tablets: How can bacteria be made into a tablet? Aren't they alive? How can they be dried? My vitamin tablets have a layer in them that's probiotic bacteria for my gut. The packaging says this is a wonderful thing because they don't need to be stored at a certain temperature, and they've got a shelf life until 2010. But aren't bacteria living organisms? How can they be dried?

ClogFilter

bad grammar — Sun, 18 May 2008 07:15:54 -0800

Should I use helpful bacteria to unclog shower and bath drains? Some earlier commenters on plumbing matters have suggested this line of products, with these species. There are also many similar commercial products often marketed as "green."

As I am not a microbiologist, I don't have a clue what the bacteria will do. Will they multiply and will a hungry Blob-like colony crawl out of my drains and go on the rampage? What will the bacteria do to the local ecosystem?

More to the point, will they actually eat the hair and hair product gunk that is probably clogging the drains?

Bacteria resistance?

Cosine — Wed, 09 Apr 2008 10:52:25 -0800

Tell me about antisceptic hand washes and building resistance in microorganisms. My workplace is putting a few new antisceptic hand wash stations on every floor. This has caused a rift amoung coworkers, half saying that these antisceptic washes increase resistance in bacteria and half saying that because the wash is alcohol based it does not contribute to super bugs.

Can anyone with more/better info shed a little light?

Old water: drinkable or petri dish?

ellenaim — Fri, 15 Feb 2008 18:03:28 -0800

How long can I leave a cup of tap water sitting out and not worry about what might be growing in it? What about an opened bottle of spring or carbonated water? I'm not looking for a tap vs. bottled water debate. I want to know how long I can leave a cup of tap water sitting out without worrying about bacteria (or some other nasties)? A few hours, overnight, days, weeks? What if I open a sealed bottle of spring water or carbonated water, take a few sips, re-cap it, and leave it out unrefrigerated for a few days?

Assume tap water that is otherwise considered safe to drink (in the US).

Would-be intestinal bacteria snob seeks counsel

evariste — Sun, 27 Jan 2008 00:13:09 -0800

So, thanks to the doctor, I'm on some weapons-grade antibiotics, and it looks like all the friendly symbiotic bacteria in my tract are going to be/may already have been destroyed. I guess this is sort of an opportunity, so I'm wondering, anyone have any recommendations for what to repopulate my intestines with? I know there are yogurts that advertise what gut flora and fauna they provide, and some probiotic milks, too. I've seen something called acidophilus advertised.

I read about one yogurt that has some kind of awesome Romanian strain of bacteria a few years back, but now I can't remember what it was!

I guess it's probably futile and I'll just end up with the bacteria from my first post-antibiotic meal dominating my guts, but I'm kind of a nerd, and I feel like I should try to take charge of what I repopulate my digestive tract with, since I have the opportunity. Any and all interesting ideas are welcome!

Re-Baking?

janelikes — Wed, 21 Nov 2007 09:11:05 -0800

Potential food born illness in baked appetizer - what should I do? So I'm headed to the boyfriends for thanksgiving (omg!) and offered to make a yummy appetizer. I chose this and made it a day early because I didn't want to have to use the kitchen while thanksgiving day dinner was being cooked.

Stupidly, I prepared the whole thing including the egg wash so that I could just pop it in the oven for 20 minutes when I got to the party. Yeah.
Afraid of bacteria, I decided to bake the yumminess a little bit so that the bacteria would be gone, but when I took it out of the oven it was perfectly done. It is beauiful and golden brown and perfect as it is- it does not look like it needs more cooking.

Is there anyway that I can refridgerate this and re-cook it tomorrow and still have it be awesome? How should I cook it so that its still perfect? Is there any chance for bacteria build up from the crab if i do try to reheat it?

This thing was expensive- probably like $40 and I would really like to not make it again...but I will if I have to.