it is extremely hard to define what is necessary chumros aside because most of what we do kashruswise is based on a set of chumros and kulos (of course there are many things set in stone)and it is really up to the rav hamachshir what to allow or not to allow based on his understanding of the situation at hand. this is why many vaad hakashrus organizations put the name of the rav hamachshir on every publication etc because that is really who decides the policies. I worked as a mashgiach in caterers kitchen for several months so i got an idea of what goes on(not the authority on the matter but some insight)
