A lot of people have "interior access", restaurants are not exactly highly classified CIA facilities. And any certification/review body can request - and obtain, if certification is worthy - such access, without any problem. Did you ever hear, for example, about Kosher certification? How do you think it can be done without access to everything? It can not. Whoever wants to sell on markets that need Kosher or Halal or any other such certification - provides access. Whoever does not - sells to people that don't care about this certification.
>>> Secondly, even then, all you can do is disseminate information. You can't enforce anything
You mean - you can't stop people from buying what they want even if you think it's bad for them, you can only give them information and let them decide for themselves if they're ok with it? Oh horror!!!