Looking for suggestions on tamper evidence for bulk super sacks

Wondering if anyone has run into good solutions for tamper evidence for product shipped in super sacks (1k and 2k varieties). Currently we tie the top of the super sack in a knot. I am currently considering using tamper evident tape and wrapping the knot, but that's kind of unprofessional looking even with my best attempts. I've also looked into using our truck seals around the knot, but hoping someone has run across something made for the purpose.

Thanks in advance for your suggestions

We use supersacks but dont require tamper evident sealing from the elevators and farms, but I think a zip-tie truck seal would be my 1st choice, and some kind of tamper evident tape would be the 2nd place idea. I haven't ever seen anything specifically made for supersacks though.

We have a client that used to do what  you are doing.  Now they do a knot and use a shrink plastic sleave (think of the sleaves that are put on hoses to stop a leak) with a numbered truck seal punched thru the sleave. The sleave is heated with a commmercial blow dryer and it shrinks around the knot.

A shrink plastic sleeve would actually be something I can see using, if I didn't have to keep a hand drier on hand. We make salt, and that eats through anything metal (corrosion resistant shovels last under a month).

I think I'm going to go with the tamper evident tape. It's not pretty but it's simple, we use it for our 50lb bags so we always have plenty, and it will meet the NSF auditors requirements (although personally I feel truck seals meet the letter of the code, it's not quite worth it to fight it out on this one).

Thanks for the suggestions and by all means if anyone else has something they use let me know!