My apologies for the delayed response - I only just stumbled across this message and thought I'd share my thoughts:
In my experience the area's that I always focus my attention on when seeing beetles are around the following at the mill:
1. Bulk tailings will indicate a spike or increased bug activity - I would definetly want to review those records for each of "my" bulk loads over the last say month to establish if there is a spike in bugs.
2. I'd also like to find out the rotation for empyting flour bins completley. How is this verified empty - through a visual inspection or through load cells? Not getting a good empty rotation on bins can be a harborage point for bugs.
2. Does the mill have an internal Pest Management team sometimes referred to as Integrated pest management (IPM) for the control of beetles. Basically I'd want to ensure that the mill is traking/trending bugs and bug activity to be able to proactively address through effective sanitation the control of beetles before it becomes a full blown explosion.
4. Is there sanitaion or IPM program effective? Tour the mill and look for dust accumulation on overheads, tops of sifters, ledges, cracks & crevices - flour beetles can live and breed in about 1/4" of flour accumulation!
5. Find out when the last fumigation was conducted. Did the mill get a good kill using the beetle cards metioned in earler post.
Unfortunatly, if you take bulk flour loads and your seeing them past your sifters into your process they are likely already in your bin. The only thing you can do to eradicate them is to completeldy empty your bin and have it cleaned - a very expensive propostion. However, if you can collect enough data to support that the beetles are coming from the mill then I would suggest that they at least split the cost of cleaning, maybe suggest they pay for the entire cleaning depending on how bad the infestation is. If an infestation is present then beetles will be seen with regularly and in consistent quantities on your end. I few beetles here and there is no way indicative of a serious problem.