It is a sub-conclusion. I find using the "Therefore Test" useful.

In this case does it make more sense to say:

"They should stop producing food waste and shut down operations immediately, THEREFORE this is not a sustainable, long term solution."

or

"This is not a sustainable, long term solution, THEREFORE they should stop producing food waste and shut down operations immediately."

Definitely the second. That means we've identified "they should stop producing food waste and shut down operations immediately" as our main conclusion because "this is not a sustainable, long term solution" gives support for it, while also drawing a conclusion based on the context.