Mycos'  MayBLater Tek

Mushroom caps, particularly those of specimens taken from the wild, are contaminated with all kinds of other microbes you do not want transferred into your spore-prints and petri-dishes. An easy way to minimize this possibility is to take your mushroom cap ( or portion of cap, depending on it's size) and stick it 's upper surface to the inside of a petri dish lid using  something like petroleum jelly (vaseline) or whatever viscous or sticky product available. Be creative. Place your sterile paper, glass slide, etc. in the bottom of the petri dish and carefully put the lid - mushroom cap and all -back on.

In this way you can keep the cap from making actual contact with the print and thereby transffering bacteria onto the print-paper as well. By taking the time to accurately  judge the thickness of the cap you can have it hovering ever so slightly above the paper, achieving a spore print that still retains it's classic "pin-wheel" characteristics, although not so pronounced. However, what you lose in aesthetic quality is more than made up for by the gains made by using good sterile technique. To a microbial pathogen, the distance between it and the paper really does mean that a miss is as good as a mile.

This technique is especially useful if you plan to culture the spores themselves. Because so few spores are needed for most projects using this, a small section of cap can be cut from the whole, stuck inside the lid and placed back over the agar itself. Usually within a few minutes enough spores have fallen. The lid can then be removed and a new, sterile lid should be used to replace the old, now contaminated one. Using this technique, if any contamination is still somehow transferred, the limited time there was for contamination to take place often means that it is limited to one area and can be successfully removed simply by sectioning and removing the affected area.

Naturally, this should all be done using a glove-box or laminar flow-hood if you got 'em. If not, a reasonably clean environment can be created by cleaning out some small area that can be cleaned with a 10% bleach solution. In theory, a light bulb or lit candle should heat the air, expanding it and thereby producuing a positive pressure, similar to what a HEPA/flow hood set-up does,  but in my opinion this is also just as likely to set up a convection type of air-current, drawing contaminated cool air in at the bottom to replace the warm air flowing out the top. But then nothing in life is 100% so as long as your doing something you like to do, hey..!