No matter what the product, there are concerns about Food Defense. Having a coop situation would add a level of complexity. I would suggest using some kind of tool to dissect each step and look at the possibilities for adulteration, then give the risks and how to counter them. Are samples taken from each load of milk that arrives that are stored for testing? I would think that the sooner a problem is identified, the less of the mixed product would need to be discarded.
An interesting question.
Have you looked at the FDA Food Defense plan builder? Even if it does not fully cover that situation, it could give you an idea how to proceed.
Very interesting question.
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