contaminated liquid innoculum??

[watertrade]

Hi,

I reciently dropped a square of agar into a few jars made up of rice malt and a pinch of brown rice floor. The mycelium seems to have grown really quickly and I can't see any obvious signs of contamination - what should I be looking for ?? I would expect to see little dark lumps of mold or to see the liquid become thicker with bacteria.

can you offer any advice on spotting contams?

cheers

Jim

[gerbil]

I'm not great with contam ID and spotting it, but you should be able to see it by discolouration of the media, some unpleasant smells or obvious growth of something that you didn't innoculate with.

Try and keep your liquid as clear as possible as it makes it easier to spot anything out of the ordinary.

If it's ready for transfer, you'll find out soon enough if it's contaminated. Suck it up in syringes if that's what you planned to do and do some trial runs to see if it's a clean culture.

[Rev]

gerbil:

Try and keep your liquid as clear as possible as it makes it easier to spot anything out of the ordinary.

bingo

but everything else gerbil said too

the BRF is good on agar but it messe with this contam spotting issue as it couds media

while i say go for it in very complex agar medai - so as to challenge and be sure to keep mycelium fully fed

in liquid go simple

even pure malt extract of dextrose syrup cn be used. Healthy myc wont lose vigour with a short term diet of sugar but over a long term it definitely will

mould contam is often lumpy in a different way to the mush myc. experience may spot it. it is also oft but not always a diff colour - grey or blacks show up well

if left o sit a week or so moulds often sporulate green or blue on the surface - a dead giveaway

with bacteria look for lack of vigour in the mycelial growth and clouding

both definite signs

thos as said the cloudiong from flour or yeast additives approximates the effect of bacteria

but as gerbil said the only definitive way to know is to run a test plat or batch

1mL squited onto a non peroxide agar plate closed and swirled and left a few days ill show up the colonies

or just go ahead and knock up a jar. if its okj then the rest of the syringe batch is fine too

if not empty the syringes, wash, sterilise and start again

youll find a clean mycosyringe is a very valuable thing - the potential for expansion is so great

[smogs]

also small bubbles/fizzing bad... as in things are fermeting due to yeast or some other unwanted stuff

i find most good mycelium is fluffy with solid white more chunky bits whereas if its just like thin cotton wool then its prolly something else

[Rev]

also dont use old cultures for liquid

once the culture reaches the edge of the plate its fine for making new plates but dont trust it for direct innoculation

as it can hide contaminant spores

esp for liquid which is very sensitive to this

use a fresh actively growing plate to make the liquid culture then make many master syringes

these should lasyt you a few grows then go back and make a new plate etc

[watertrade]

hmm .. big risks for big returns.

so far so good though, I will do a few tests onto grain and see how it turns out - I'm not that worried about it, I was just playing with the left overs of a petri dish.

I will probably do some more sterile syringe to liquid transfers just for piece of mind

Thanks for your help

Jim

[Rev]

The risk is only your time - if you always batch test

this way you can see the purity by testing on an agar plate and you save wasting all that effort and substrate

all u wasted was some time and sterile water

yeah syringe to liquid is far better

so far as the wedge to liquid goes i gave that up ages ago - and i have a laminar flow

its too easy to mess up

agar to syringe to liquid is far safer

[watertrade]

agar to syringe...

this is new to me... How to I force a wedge of agar up the needle of a syringe??? :D

Jim

[Rev]

well theres a tek to write up then

its a matter of squirting some water on, scraping the surface of teh petri with the needle and then sucking up the fragments

these are then used to inoculate the liquid culture

it needs pictures