Mold in Plastic Water Bottles? What does it eat?

  • Thread starter Algr
  • Start date
In summary: It has a green substance in the bottom. It almost looks like mold but I'm not sure.In summary, algae can grow in water bottles that have been reused multiple times. The presence of this algae can potentially contaminate the water in the bottle.
  • #1
Algr
870
396
So I reuse these plastic bottles, and fill them with filtered water from my tap. But eventually they start growing something green inside:

Mold in water bottle.jpg


What is this? Presumably anything alive would need to be eating something. It can't be metabolizing the plastic, surely? Does my water supply have proteins or sugars that get through my filter? Are my lips full of nutrition that something eats when I drink from the bottle?

These bottles are maybe six months old. I've refilled them maybe ten times. When I notice this, I have to buy new bottles. IDK if trying to wash in there would be effective. I don't want to end up drinking soap either.
 
Biology news on Phys.org
  • #2
Algr said:
So I reuse these plastic bottles, and fill them with filtered water from my tap. But eventually they start growing something green inside:
Algae? More to your question: plastic straws/water bottles/other hospital "souvenirs" eventually/usually grow black molds/fungus at ca. one week; plastic bread wrappers seem to generate penicillin molds (blue) spontaneously, while still on the shelf in the store.

Polyethylenes are all porous to some degree, and pick up spores from the storage environments.
 
  • Like
Likes Laroxe, symbolipoint, pinball1970 and 3 others
  • #3
Algr said:
Are my lips full of nutrition that something eats when I drink from the bottle?
You drink out of gallon jugs? hmmm.... I also reuse plastic bottles but nothing over a liter. I often get bored drinking tap water so I often put in Tang or some other flavored mix. This tends to taint the insides after several uses so I put a drop of dishwashing liquid, a couple of drops of laundry bleach, water, and a dish rag inside the bottles and shake the bejezits out of them. I've discovered that without the dishrag, the inside does not clean up. And I now only buy widemouth bottles so I can get the dishrag in and out. And I rinse them until no foam is generated. Any residual 'bleach' smell is probably way below the levels acceptable according to the EPA: 6 drops per gallon

And yes, things in your mouth can can contaminate the contents of the bottle. When I first bought my microscope a couple of years back one of the first things I did was brush my teeth in the morning with a clean toothbrush and no toothpaste, and found both bacteria and fungus in the sample. One of the more disgusting things that happens is if I'm drinking something with sugar and I leave the bottle sit for a day after drinking out of it, is that the bottle will sometimes pressurize from whatever decided to ferment the sugars.

I don't recall ever growing anything green, but I keep my bottles in the fridge or next to my lazy boy out of the sun, so I wouldn't expect any algae growth.

And before you run and tell your friends that I'm some kind of disgusting filthy pig, be aware that; "Do you know what’s in your mouth? It’s home to about 700 species of microbes. These include germs like bacteria, fungus, and more."
ref:
NIH
 
  • Wow
  • Like
Likes BillTre and Algr
  • #4
Bystander said:
Polyethylenes are all porous to some degree, and pick up spores from the storage environments.

Er... Waitaminit! Spores from outside can get inside a closed bottle? Wouldn't that be a major health issue?
 
  • Like
Likes BillTre
  • #5
Algr said:
Er... Waitaminit! Spores from outside can get inside a closed bottle? Wouldn't that be a major health issue?
You are right spores are too big for that.
Water molecules can soak into many plastics, at a slow rate.
 
  • #6
Algr said:
Er... Waitaminit! Spores from outside can get inside a closed bottle? Wouldn't that be a major health issue?
The films/bagstock.
 
  • #7
Algr said:
Er... Waitaminit! Spores from outside can get inside a closed bottle?
There also is no thing as a closed system in practice :wink: Your closed bottle probably has a cap, and if it has ever been ever opened, and unless your apartment is a clean-room with filtered air, all lots of stuff can get in there once the cap is off.

It's scary when you realize how much airborn particles there is in normal indoor air (or probably even outdoor air for that matter), that normally isn't visible to the naked eye.

/Fredrik
 
  • #8
Fra said:
Your closed bottle probably has a cap, and if it has ever been ever opened, and unless your apartment is a clean-room with filtered air, all lots of stuff can get in there once the cap is off.
That part I understand. It just sounded like something that could happen while the jug was still being shipped.
 
  • #9
Same issue, with a capped glass bottle for plant watering that's been rinsed out with boiling water on several occasions. I think the green stuff (algae?) was eating a bug that had fallen in. Inside of the cap has a black ring.
 
  • #10
I just noticed that I have a 1 gallon clear jug that is 7 years old that I routinely fill with water and leave outside in the sun and I've never noticed anything growing inside it even though the water comes straight from my tap. I use this bottle to fill my cats' water dishes. I'm still of the opinion that it's backwash that's feeding the green whatever colony.
 
  • #11
I refill regular 20oz water bottles and have been using the same three for about a year, and have zero growth of any kind, BUT ... first, I never drink directly out of them and second, I only take the top off very briefly to either pore the contents into a mug or to refill them and third, I keep them in the refrigerator.
 
  • #12
The material the plastic bottle is made out of ay have an effect here. No one has said what their bottles are made.
In addition to differences in what they are made of, some plastics also have chemicals in them which can leach out: plasticizers, UV inhibitors, anti-fungal agents, for release compounds, perhaps others as well asa plastic breakdown products. Some of these could feed whatever can grow in there.
In further addition, the water used to fill the containers could contain other materials, including fertilizers.

One could try it with a glass container and possibly a more pure sample of water.
However, not all glass containers will not add material to the water.
 
  • #13
BillTre said:
No one has said what their bottles are made.
They are just gallon jugs that I bought at the store and keep near my bed. I drink from them and fill my cpap, so that I don't have to go to the sink every time I feel thirsty at night. I didn't look that closely at what they are made of, but it has happened more than once, so kind of plastic might not be relevant. If I kept a glass near my bed I'd need to wash the glass, so same issue.

So my breath has enough nutrients to sustain plant life? Maybe that "talking to plants" thing is connected.
 
  • #14
Algr said:
If I kept a glass near my bed I'd need to wash the glass, so same issue.
Glass would be much less likely to leach chemicals into the water. This is a potential contamination source.
I would think the issue would glass would be potential breakage.

If you don't know about the plastics, you could just try a:
  • different container of the same material (test for an established growth in the bottle not washed out)
  • duplicate containers, same materials, not used (test for effects of human contact)
  • different containers made of a visibly different plastic
If you could reuse containers sold with food in them, they would be food grade. Or if the container you bought were "food grade", that would also be good. A food grade rating indicates the plastic meets certain standards about not contaminating things. If they had food, they would have to be well washed out first though, to remove the food residue.

Since there is a concern about contamination, I would include a sanitizing or sterilizing step.
Its easy to do. After washing, rinse with some bleach (add a little and swish it around), rinse out repeatedly (with clean water) until no smell. Invert. Let dry.
If you have a pressure cooker, you can autoclave (steam at pressure) your container. This is one of the best sterilizing methods. However, only certain kinds of plastics can withstand this.

Plastics is a term that covers a large variety of different chemical materials with different chemical and physical properties.
Knowing the materials is really helpful in diagnosing problems associated with them.
 
  • #15
If you decide to "disinfect' the water to avoid algae or critter growth, there is an informative article that also covers container material at:

https://deq.utah.gov/drinking-water/emergency-water-storage

Each gallon of water should be treated with 4 – 5 drops of liquid chlorine bleach...

Cheers,
Tom
 
  • Like
Likes Rive and BillTre
  • #16
This may be obvious:

The OP made a point of stating that he fills his bottles with 'filtered' water. That likely means a charcoal filter. That likely means little/no chlorine in the water. Anything present in the bottle (however introduced) continues to grow. If (instead) the bottle were recharged with 'chlorinated' water, the population of whatever would be reduced/eliminated.

Persistent disinfectants (like chlorine) are added to public water distribution systems even where the primary disinfection method is something else (UV, Ozone...). That's to prevent the whole system from behaving like OP's used bottles. Removing the disinfectant at the point of use is fine, but remembering why it's there is sometimes important.
 
  • Like
Likes Tom.G, BillTre and hmmm27
  • #17
This has happened to me. Although I was using a gallon jug that had just been emptied of the distilled water and then filled with tap water. It sat on the shelf next to the new bottle of distilled water (which is opened and used weekly), but the jug of tap water had cloudy clumps of something it, even though it had not been opened since filling it. Same brand of plastic bottle. I always thought there was something in tap water that made it do this, as the distilled water never does (even if transferring new distilled water into an old distilled jug - some jugs are easier to pour).
 
  • Like
Likes 256bits
  • #18
The "filtered water" could have an additional problem.

A few months ago a neighbor asked for help changing the filter in his filtered-water pitcher (he is partially paralyzed and also not good at figuring things out).

The filter smelled of mildew/mold and the pitcher cover had red algae growing in crevices.

Just noting here that a particular problem can have various possible causes.

:eek: Tom
 
  • #19
howdypez said:
This has happened to me. Although I was using a gallon jug that had just been emptied of the distilled water and then filled with tap water. It sat on the shelf next to the new bottle of distilled water (which is opened and used weekly), but the jug of tap water had cloudy clumps of something it, even though it had not been opened since filling it. Same brand of plastic bottle. I always thought there was something in tap water that made it do this, as the distilled water never does (even if transferring new distilled water into an old distilled jug - some jugs are easier to pour).
precipitation of minerals in the tap water.
 
  • #20
Tom.G said:
The "filtered water" could have an additional problem.

A few months ago a neighbor asked for help changing the filter in his filtered-water pitcher (he is partially paralyzed and also not good at figuring things out).

The filter smelled of mildew/mold and the pitcher cover had red algae growing in crevices.

Just noting here that a particular problem can have various possible causes.

:eek: Tom
Here's an idea. Get a clean closable metal water container; be sure it is freshly clean. Boil some water for a couple minutes in a pot or kettle. Fill the metal water container, close-on the lid, and let the apparatus cool. There! Clean drinking water!
 
  • Like
Likes Tom.G
  • #21
symbolipoint said:
Here's an idea. Get a clean closable metal water container; be sure it is freshly clean. Boil some water for a couple minutes in a pot or kettle. Fill the metal water container, close-on the lid, and let the apparatus cool. There! Clean drinking water!
You know why tea exists, right? Also, Tom's neighbor might not be capable of all that.
 
  • #22
Algr said:
You know why tea exists, right? Also, Tom's neighbor might not be capable of all that.
Just a way to prepare clean fresh drinking water. I did this on occasion. At least it would start with no algae and very few other microorganisms. As for why tea, I would only guess; one reason for might be to improve the flavor of water.
 
  • #23
BillTre said:
Glass would be much less likely to leach chemicals into the water. This is a potential contamination source.
I would think the issue would glass would be potential breakage.

I don't know how common this is, but some glassware that looks like it's a single piece is actually several pieces stuck together. Like, a bottle or glass may consist of an open tube and a separate bottom. I imagine whatever they use for glue is going to be a likelier source of impurities than the glass itself.

BillTre said:
Its easy to do. After washing, rinse with some bleach (add a little and swish it around), rinse out repeatedly (with clean water) until no smell. Invert. Let dry.

In my experience, the inside of plastic containers with small openings dries more quickly less slowly when the container is right side up, once any drops that are big enough to fling or run off are gone. My guess is that this is because the rest of the water simply sits there until it eventually evaporates, and that the vapour escapes from the container more easily upwards than downwards.

If this is true, and the reason that (smooth) ceramics and glass dry more quickly is that less of the water evaporates and more gets removed by other, more efficient means, that might well be another contribution to plastic containers being less hygienic: The more evaporation, the more residue.

Tom.G said:
The filter smelled of mildew/mold and the pitcher cover had red algae growing in crevices.

I'm supposed to change my pitcher's filter every month (it's even got a little light in the lid that switches from green to red when it's been too long). I've experimented with leaving it longer, and eventually it'll start to grow green stuff that looks a lot like that in the OP's picture. It doesn't grow in the bottom of the pitcher, though, but in the part that one fills with the unfiltered water and that the filter itself sits at the bottom of. The manual mentions that the main mechanical/structural element of the filter is an organic substance (https://en.wikipedia.org/wiki/Coconut_fibre), so my assumption is that that breaks down after a while and then releases nutrients that the algae (or whatever) feed on.
 
  • #24
Its worth remembering that the main requirement for plant growth is sunlight and CO2 and once a liquid is exposed to air other things get in there. Mechanical filters simply concentrate any solids in the water, so become good growth media. So storing previously boiled water in the dark with a minimal air-space unopened will keep it fresh for some time. Chlorine dioxide is the go-to chemical, as it doesn't affect taste too much, though needs time to work and looses its activity fairly quickly. This is one of the reasons that silver containers were popular, the silver, given time, would kill a lot of organisms.

None of these things are perfect, life is everywhere and very persistent, but luckily green algae is rarely a health risk. Remember, we used to use particular organisms to protect us from things in our drinking water, you don't believe that beer and wine were adopted because of their taste do you.? :)
 
  • Informative
  • Like
Likes symbolipoint and BillTre

Similar threads

  • Biology and Medical
Replies
22
Views
4K
  • Biology and Medical
Replies
1
Views
1K
Replies
20
Views
3K
Replies
3
Views
1K
Replies
12
Views
1K
Replies
3
Views
2K
  • Chemistry
Replies
7
Views
3K
Replies
8
Views
3K
Replies
12
Views
2K
  • Biology and Medical
Replies
3
Views
4K
Back
Top