>Can he guarantee his pressure cooker autoclave works, and if so how?
Autoclave tape
Just because one utilizes alternative materials does not mean the scientific method goes out the window. Finding a repeatable process is paramount.
Also, many of these DIYbio projects take advantage of methods used in labs for years. There are multitudes of testing procedures, validations, ect that enable one to see if their over the counter laxative is up to par.
I agree with what your saying, but at the same time many such tests have been developed to work with biochemical grade components. Yes - they may test if X has worked, and that Y and Z are not present, but if there is no expectation whatsoever that A is present then it won't be something worth testing for normally, even if, in this rather specific example, there's more A than you can point a stick at.
Repeatability does not necessarily reflect functional correctness. Clearly this is a bigger issue than just DIYbio, but my point is simply that if you're working in a lab, under lab conditions, you can make a lot more guarantees regarding continuity of environment, materials, and methods than you can in your mum's spare room with over the counter laxative.
Equally, however, assuming "the traditional" is the only way to go is a dangerous precedent too. I'm just of the possibly naive opinion that it would be difficult to follow the scientific method to as rigorous a standard as is necessary, but perhaps that in itself will precipitate a new industry in low cost biotech equipment.
Autoclave tape
Just because one utilizes alternative materials does not mean the scientific method goes out the window. Finding a repeatable process is paramount.
Also, many of these DIYbio projects take advantage of methods used in labs for years. There are multitudes of testing procedures, validations, ect that enable one to see if their over the counter laxative is up to par.