Making Petri Dishes

[@riccardocarbo2479]

I think 15 minutes is the standard using a pressure cooker/autoclave. Regular boiling (not pressured) takes 40 minutes. Thanks for the info! Btw... I wish you'd say "sterile" versus "clean." There's a real difference.

[@brightbiology9632]

You are correct and thanks for the information.

[@user-xb1ht4py2v]

How long to kill mold and fungus spores?

[@allisonbuhay2245]

Hi! Just wanted to say thank you for making the video!! It was really thorough and easy to follow, and really helped me out with my science fair project. :)

[@shibasquad7059]

same here

[@granderondeproductions3286]

I'm surprised you're not using a still air box! I'm learning how to grow Shiitake mushroom and I'm starting from a Liquid Culture. My first two attempts were completely a bust, but then the next two were perfect and have clean mycelium on them. So I'm a bit excited for that!

[@brightbiology9632]

I use a plastic box with seed heating mats. I call it the hillbilly incubator.

[@user-xb1ht4py2v]

@@brightbiology9632 I think they are talking about sterile transfer box, not an incubator. Im curious as to why you did not have a bunsen burner or alcohol burner going to help keep a," cone of sterility" as i have seen in other videos and books? Any reason, or is it not needed when just making plates?

[@SakkiDuran]

Hey you left me wondering 2:57 why did you put those in there?

[@tinkerbell6412]

It's really helpful for me, thank you, sir!

[@tracysamuels8754]

Hi..What is the actual Full recipe for making the liquid agar please..as I don’t see the amounts tht used..( I may hv missed them cause I’m disabled) but I would b v happy to know thanks xxx

[@dezyrides2519]

why don't people put the agar in the dish and then pressure cook the whole thing?

[@fishmut]

Because those Petri dished are plastic , they would deform from the heat they are not glass , you can buy glass ones though , they are not cheap.

[@ellleHOP]

Hello, it's a helpful video! I have one question about the water though. Can I use water from the tap, or is it a must to make agar with distilled or purified water? Thank you for your time!

[@brightbiology9632]

I use tap water.

[@bamba2046]

Great video thanks!

[@dummkompf]

are you just pouring them in open air?

[@eph3672]

I don't have an autoclave or a pressure cooker. Can I just put my agar mix inside a jar, and then place it in boiling water for some time?

[@granderondeproductions3286]

Actually yes you could do this. there's a channel called 90 second mycology (which has more to do with Mushrooms but the guy covers some agar stuff which is pretty neat). Just look up no pour agar on that channel. pretty ingenius.

[@youngchef2470]

Hello are the styrofoam cups necessary or just an added exparement

[@brightbiology9632]

Just for an added experiment.

[@shubhamdhall2448]

The video was nice but I wish that your camera didn't blur the part when you were filling the beakers with agar.

[@gjorgjiristov4644]

hello is it better if i use 40% normal water and 60% water from boiled yeast and all that mix with agar ?

[@bityote]

Why do you store them upside down?

[@bityote]

I should have researched a little more first. I see it is due to preventing condensation on the sample. Excellent video!

[@TammyOzuna-rn8jf]

@bright biology- can I use a UV light to sterilize petri dishes?

[@user-xb1ht4py2v]

I wouldnt count on it. The UV light could be getting filtered out even though the dishes are clear. You could easily do some tests, it may work out.

[@ChilSc]

Final someone to put “Dr. Edward Grand” in his place he’s supposedly gone to college for at least 8 years in his own words yet he still acts like a psychopath when you ask him about something he doesn’t know about.

[@michelleimage4200]

Hi, why does my petri dish didn't solidify? I used 1tsp sugar, 1tbsp agar, 1 knorr cube, 1/2 cup of boiled water

[@brightbiology9632]

Might be poor agar, or you didn't let the agar dissolve completely?

[@michelleimage4200]

@@brightbiology9632 I completely dissolved the agar. Then put it on ref but it didn't solidify

[@arteal33]

@@michelleimage4200 overcooking the agar can be a problem

[@tinkerbell6412]

@@michelleimage4200 maybe the air condition was pretty heated or in a hot condition...

[@michelleimage4200]

@@tinkerbell6412 oh okay. Thank you

[@thhomasmarks]

Excellent present (link to wrist computer)

[@kikiqt2442]

This is really helpful! Question though, when I was researching about the ingredients I needed it said to get “Dry Malt Powder” but I’m not sure what that is used for or how much I need. Also would using “Agar Agar powder” work the same as what you’re using?

[@homesynthesis]

Agar agar powder won't contain nutrients required to support culture growth, but you can create nutrient agar powder using agar agar powder. You can probably find a recipe online, but I imagine it'll be some parts agar agar powder and some parts potato starch or malt powder or sugar.

[@wombatkins]

Wait is that a stir plate?

[@funkblack]

I can't identify agar for microbiology in my country. Will any vegetable agar work?

[@brightbiology9632]

I would think so. I have used jello before and that worked.

[@glorygloryholeallelujah]

I don’t know if this would be any easier for you to find in your country… But guar gum has worked for me in a pinch. 💗👍

[@chicagorhtours]

Why can't we just do the bacteria experiment on the sterile petri dish? Why do we need this agar stuff? I want to check my neighborhood bar for bacteria, cleanliness - offer to clean and disinfect them on weekend nights.

[@brianabananaslava]

The agar allows you to grow the bacteria, it acts as a growth environment and food source for the bacteria. If you just had a plain, empty dish, nothing would happen.

[@Chloekat1234]

Bacteria can’t grow without nutrients

[@jessicahewitt351]

What is the purpose of the styrofoam cups? I understand the properties changed but not the reason for adding them.

[@brightbiology9632]

Just for fun and to show that there is a large amount of pressure in the pressure cooker.

[@jerseyhovidea]

Hello, can I pour the mix to the glass petris, pack it to al foil and than sterilize it in pressure cooker?

[@brightbiology9632]

That seems like a lot more work and I think maybe the media would boil out of the petri dishes.

[@jerseyhovidea]

@@brightbiology9632 Thank you! I guess I could give it a try, seems more sterile in my conditions without a laminar flowhood. Or maybe a alcohol lamp would do the trick...

[@eggsalts4243]

@@jerseyhovidea use a still air box buddy… or hear me out, get the 4oz mason jars and they won’t boil over if you go just under the agar line with the water line

[@jerseyhovidea]

@@eggsalts4243 thanks mate!

[@overover..]

Why can no one pronounce agar?

[@supasye]

Why store them upside down?

[@brightbiology9632]

To keep moisture droplets from the lid falling onto the media.

[@ammuluammu6789]

For how many days it can be stored sir

[@brightbiology9632]

If you place them in the fridge, I have let them stay there for weeks, but they will begin to dry out.

[@sxmxrxz]

@@brightbiology9632how many estimated days or weeks before they begin to dry out ?

[@dastanharris]

do you add water into the pressure cooker to create steam?

[@brightbiology9632]

Yes, you need water in there!

[@Shadow-mm3cg]

i always do the same thing but my agar is always cloudy and doesn’t mix, any ideas?

[@brightbiology9632]

When that happens to me it is because I didnt boil/pressure cook it long enough.

[@AvatarMakusan]

Appreciate this video! What is the difference between nutrient agar, MEA, and PDA?

[@crypto_dasha]

Same question

[@brightbiology9632]

They are just different types of plates made from different materials. Many times people will use different types of plates to isolate various bacteria or identify them.

[@user-xb1ht4py2v]

PDA----Potatoe Dextrose Agar. MEA-Malt Extract Agar. all use agar for the jelling, but different nutrients. Depends on wht you want to grow. The nutrients are the food for the bacteria, or fungus or wahtever it is you want to grow. Different things like tt eat different stuff.

[@Pet_Hedgehog]

would it be possible to use syringes to transfer the agar from the beaker to the dish?

[@brightbiology9632]

I guess, but that is one more thing that can contaminate your dishes.

[@Pet_Hedgehog]

@@brightbiology9632 hmm true, would need to use new ones each time but i think it could be possible.

[@chance6itch]

Can this be used for mycology?

[@alexbrown2666]

Yes.

[@z0quetee]

Is it possible to use xanthan gum instead of agar?

[@brightbiology9632]

I don't know. Never tried.

[@tinkerbell6412]

I don't think that's a good idea..

[@z0quetee]

@@tinkerbell6412 FYI, I tried it, it worked

[@tinkerbell6412]

@@z0quetee wow, okay then.. New information for me, thanks!

[@Zzaaccharay]

🧫

[@jackmchenry4576]

Talks about starility yet literally talking over, and not using gloves. 😅

[@rrtsduf]

Just use petri vials ffs.

[@crypto_dasha]

Great video!

[@brightbiology9632]

Thanks!

[@Johnspeacefulchaos]

@Brightbiology did you pour them in the petri dishes hot?

[@brightbiology9632]

Yeah, but not right out of the cooker hot.

[@youngchef2470]

Can you do half dosage or do you have to do the full recipe

[@brightbiology9632]

You can do a half batch.

[@alfredforbessealy524]

2:26 you guys make hot cocoa with water ??

[@brightbiology9632]

I dont usually, but in a pinch I do!