5 replies to this topic

[Weiner.C]

hi All,

my lab have preform a regular test for Yeast and mold using the normal test method ISO.
the result is as you can see in the pic, the mold have spread all over the plat, i have inquiry two external lab i work with and they advised that i can count the result as one colony (10 cfu) another lab say that it considered to be uncountable = unqualified >100cfu.

i would have preformed another test 1:1000, but i don't have 5 days to wait, i was wondering if someone here have encountered this before and could advice on the result.

i have made the test 4 times and every time i get the same result, this is from the same batch and LOT so i confident with the operation, all other tests i preform in the same day are qualified, i have issues only with this tests (BTW it is cumin powder).

appreciate your reply.

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[zue_rais]

ensure essayed plates are dried upside down before incubation, in normal practice, it would be counted as 1 colony due to swarming

[Weiner.C]

ensure essayed plates are dried upside down before incubation, in normal practice, it would be counted as 1 colony due to swarming

hi,

after we add the agar we let it dry for some sec and than insert to incubation. i cannot completely dry it upside down or else it will spill to the cap.

pls advice.

[Dairy]

From ISO 4833 which granted is for standard plate count.... we still use this principle for all plates.

HTH - Dairy

9.3.2 Spreading colonies shall be considered as single colonies. If less than one-quarter of the dish is

overgrown by spreading, count the colonies on the unaffected part of the dish and calculate the corresponding

number of the entire dish. If more than one-quarter is overgrown by spreading colonies, discard the count.

[Charles.C]

hi,

after we add the agar we let it dry for some sec and than insert to incubation. i cannot completely dry it upside down or else it will spill to the cap.

pls advice.

Dear Weiner.C,

No direct experience of yeast count plates but for standard plate count / pour plates usually means you have a media, preparation or sample size problem.

Rgds / Charles.C

[Cranberry]

Hello,

What type or media is the lab using? and is the lab nationally accredited?

The organisms (probably mould) have spread and from when I used to work in a lab the plates you display would be unreadable.

Some simple microscopy could give you some information about the organism responsible if you wished to investigate.