| Brookn, it's surprising how successful this can be if one knows something about sterile technique. Like Andrew, I worked all my working life for companies that had autoclaves (some big enough to park your car in) laminar flow hoods, balances, etc. However, some companies frown at employees who sign security sheets at 1 AM upon entering the plant and don't leave until 5-6 PM later that day. So, sometimes you just have to be creative. I really never kept track of the success rate by either method, but I don't think I ever had a contaminated flask when I worked under the hood. Can't say the same about home but imagine it was around 60% successful as far as mold contamination is concerned.
Andrew brings up a very good point. Most of the plastic containers around the kitchen are not meant to be heated to the temperatures you will achieve in a pressure cooker and maybe not even the microwave. I preferred to use either Pyrex milk bottles sealed with rubber stoppers with one hole thru them that I very tightly packed with cotton. I sometimes used glass RX bottles that I could buy at a local pharmacy. I don't know if you can do that today, seems like everything is plastic these days.
You may well be correct Andrew about microwaving. However, you would be amazed these days how many surgical instruments are sterilized via microwave. Most mold spores do not desiccate very well (one of the reasons I leave the seed in a Tupperware container with silica gel). Even the spores have some water and protein in them and the protein (and especially lipids) heats much faster than much of the surrounding material. I have personally never sterilized media in the microwave, but have talked to many that have and they seemed to be successful more often than not. Most home areas do not have an area clean enough not to have spores in the air and when you remove the bottles from either pressure cooker or microwave, they will draw in air from the outside. Many people do not realize that this is often a major source of contamination. In any case while I may not completely agree that it is impossible to sterilize media in the microwave, if I can find a pressure cooker guess which one I would use!!
Having been involved in mammalian cell culture for over 40 years, I must disagree that a complete medium can not be made as a homogeneous dry powder. Bacteriological media have been prepared this way for years! Also much of the mammalian cell culture media is made the same way. It is really amazing just how fine those ball mills of today can grind!!
TC, one major problem with buying the individual chemicals individually is that most homes do not have proper storage facilities for them. Some of the small diet scales today are probably sensitive enough to weigh out complete media (it really isn't rocket science) but I doubt you could get the accuracy needed with individual components. I just can't imagine anyone trying to weigh materials that are very hygroscopic this way (anyone who has had to weigh out small amounts of Choline Chloride knows what I am talking about).
Anyway, I still think that unless one has had some experience in working under sterile conditions and has minimal equipment at their disposal should spend their money in buying postage to mail off the pod. However, if one just has to try, as TC and Andrew have pointed out, at least use a good flasking media and not some witches concoction. I really shudder when I read some of the "formulas"?? being contemplated!!
Let me give you one reason why you may want to use an outside flasking service. First, you need to check around and make sure that the lab is considered to be one that knows what they are doing. I don't know how many of you have seen Phrag Silver Eagle, but the hybridizer collected a pod from the first cross and had it flasked. There have been at least 4 quality awards from this cross. Up until a few months ago, the hybridizer has remade this cross a number of times with absolutely no success. Had they used all the seed from the first successful cross in experimenting with home recipes and home flasking, the cross may never have been seen!  |