Lot numbers in bulk and/or continuous systems
Background:
Situation A -- We have 10+ silos that house flour, oil, sugar, and gluten. We receive multiple loads into silo's on a regular basis (daily, every other day). Silo's are sometimes completely emptied and are cleaned 2x/year.
Situation B -- We have 10+ minor ingredients that are each put into bins (maybe 1000-2000 lb/ bin). Once placed in the bin, the rest of the system is closed as each ingredient is weighed, mixed together, and put into a bag. The system can be 'purged' on a regular basis, but not fully cleaned, and the bins can be completely emptied.
Question:
In either situation if Lot A of an ingredient is put into a silo or bin, we have record of that. Since the bin/silo isn't completely emptied, at what point (amount of time) is Lot A considered negligible for tracking purposes? Does emptying out all bins an adequate 'reset' for lot #'s, or does a full cleaning of the system need to take place?
We are moving towards an electronic method of lot tracking for these ingredients, and we are struggling with at what point do we no longer consider Lot A being in the system. Any suggestions/recommendations/guidance?
Thanks!
I think that the approach should be a little subtractive. The question is in a silo how many different lots there will be together? Let's say two. In the system of the production should record that during the production of an exact lot we had these two different lots that were used. It's the most honest thing to do and the most sensible one. If something comes up with the raw material or the product itself then, you can check these two lots.
Hope I helped a bit!
This is a classic silo problem and IIRC has been previously discussed here.
There are theoretical papers published on this also but I cannot remember how good a solution was achieved. A little searching maybe.
Since there is no restriction on the “ lot size” in your final product as long as all units belonging to the same lot has been produced essentially under the same conditions, one of the things you must think about is “ how much or how many units I am willing to recall “. Of course, on your production records you must indicate which lots of “ silo storage raw materials” were in place by that moment.
On the other hand, for me, it is not the same to talk about “ powder product in a silo” than “ liquid product in a silo”. In the first case I am sure that studies can be done and new technology/design/ engineer idea can be applied so that a reduction of the size of recall units ( raw material ) would be possible.
However, in my opinion, and having in mind the concept of traceability, what I would do is to first think about all these issues so that you can analyze the capacity of silo or design of silo that suit you better.
Regards