After consulting an expert in cheesemaking, and feeling some responsibility for the content on this web site, I feel a need to caution you regarding some risks in home cheesemaking.
I stress the need for a sanitized workplace and equipment because pathogens harmful to humans can make their way into cheese. I encourage the use of the freshest ingredients as well as sanitized equipment and careful handling of ingredients. For example, I have a bleach/water solution in a spray bottle that I use on all surfaces and to clean and sterilize all cheese making equipment like pots, spoons, measuring cups, knives, presses, etc.
I also encourage the use of fresh cultures rather than cultures harvested from existing cheese. Neil, we may differ on this point. Let me make a few observations:
If you use an existing young cheese to get the culture you want for a home made cheese, you will likely get the culture you want, but you may get other things too. To quote the expert I consulted, “This is very doable ... but the problem is you do not know what else you are getting ... probably lots of yeasts and other molds and surface bacteria (listeria could be a problem here).”
And, if you use older, aged cheese as a culture then, “that is a bad idea since the viable culture at aging is in an exhausted state at best post aging and usually has little to do with what made that cheese.”
If you don’t want to use purchased cultures, then try to rely on the cultures in raw milk if you can find it.
I guess my input is that if you want to use existing cheeses to culture new cheese, please be careful. Continue to sanitize everything compulsively, and use only the very center parts of an existing cheese immediately upon cutting into it. There are dangers including listeria, clostridia, and others…
