An intuitive suggestion for improving the sterility of your kitchen lab.
Here is a method I've been using for over 15 years. If you follow it correctly you can open/close jars, do inoculations etc all while staying sterile. First you need an expensive piece of equipment, an oven. Lucky for most we have already made that investment. If you don't have a oven, don't buy one, go get a HEPA filter instead. Now for those of you with ovens. Turn your oven on the lowest heat setting. Pull one of the racks out far enough that you can set stuff on it and also work on it. Place your jar/sporeprint/agar on the rack and open it, only after the oven has heated up and there is a steady flow of warm air rising. The steady flow of air will keep anything from dropping on the jars. As long as you use a breather, or don't breath close to the jars. Of course everything else needs to be sterile, knives/loops/hands so that you don't contaminate things that way. Basically this will stop all Airborne particles. Anything else needs to be clean. If you don't have an oven, or your racks don't pull out nicely, you can build a rack above a range and turn it on, same principle. I've tested this many times over, even have won bets after leaving jars open for 30min + on the rack and not having any of them contaminated. In theory, a fan should work the same way, say a fan underneath a rack, but it doesn't, I've also tested that. Any jar open more than 10min with a fan under it has been contaminated, shrug. I figured I'd post this since I've been doing this for 20 years and never heard/read about anyone using this technique, but it works quite well.