>>11439876Plating has its purposes. Depending on media you can select for brewing yeast, wild yeast, anaerobic or aerobic bacteria and moulds. Between those tests you can determine quite a lot, there is just a few draw backs ...
- sterility
I have to plate at least 3 to ensure a reliable result. One I could easily mess up and contaminate and a second is to check the other one.
- time
I have to hold plates warm under correct conditions and won't learn a lot for 48 hours.
- space
I have to have the space to work aseptically with plates, prepare plates, store them, hold them etc, it is a step up in effort and I'm not there yet on it for routine tests.
Also unless sterile (impossible unless sterile filtered or pasteurised everything is compromised to some extent. The key is defining an objective measure of 'normal' and determining 'normal' shelf life.
At the moment I've data going back several months and can confidently say less than 5 CFU's per ml will give me minor pH drop over 4 months held at 25C. This counts as good enough for me because at cold storage temperatures those 4 months can easily be extended out to 6 months and I don't need to worry about greater than 6 months yet.
Just as I said in OP. Many test fine initially, but go on to develop issues anyway because my micro methodology could use some work. I figured a stain might help.
Pic in OP is well developed. You can see the chains formed by the coccus. On day 1 a coccus is a cocci and they are quite easy to miss.
