That sounds like a really neat idea!
I will honestly say that I am doing that so don't know anything for sure, however, I am putting my reasonings in for some ideas that may help you going forward.
I would look into the traceability a little more. For food manufacturers or something like that, you should be able to trace one forward and one back. So, even if you don't put the traceability on the box, if you know which lot numbers of, say, flour for example, were sent to which customers on which day, you should be fine. The way to definitely have your bases covered for this would be to just use a label system and put the lot number on each bag of each ingredient. Of course, that is incredibly time consuming and costly to use all of those labels and I doubt anyone else does that. I work for a company who makes paper products for food packaging. We put the lot numbers on each of the boxes we create which then get sent to the food manufacturers. I believe from there they just keep track of which lot numbers of our products are used with which lots of their products but don't actually record our lot numbers on their finished products. I would assume if we had a recall, they would have to recall all of their lots that could possibly have been manufactured/sold in our containers. Using this assumption, if you knew which lot numbers were used when, you would still be able to have an effective recall without having to put the traceability information for each ingredient on each box. However, I would make sure to record ALL traceability information. So if you were to use Ziploc bags to put the ingredients in, I would make sure to record the lot numbers of the Ziploc bags you used, etc. We record the box lot number, the bag lot number, all of that because if any one of our suppliers were to have a recall, we want to know which boxes of our finished goods could be affected.
As for the warehouse and shipping, I would just make sure they have a pest control system in place, a chemical/ hazards system in place, and is a generally clean facility. You don't want to have the bags of ingredients leave your facility in a good condition and come into contact with pests/ rodents/ chemicals/ dust and then be placed and transferred by the consumer onto their kitchen counter. I would do a "mini audit" of their facilities just to ensure that it is safe. And you might think about having a documentation for the truck/trailers that come into and leave your facility to ensure that the doors are either locked or sealed and the trailers are in good condition: no signs of pests, no holes, not too dirty. Just if you are using full trucks to transport between facilities. Obviously, once the food is packaged and being sent to consumers by FedEx or UPS or whomever, you can't really make this rule. I know this may seem like going overboard, but I would rather be safe than sorry. If you do ever do a full audit by a third party, you would probably need to have these systems in place and it's much easier to start out that way than changing things up on your suppliers overnight.
Like I said before, I don't have any documentation to show you that you definitely need all of this. So definitely ignore all of it if you think it's too much or determine it is unnecessary. Just throwing out some (very wordy) thoughts :)
Good luck!
