When called to an account for what you determine is a stored product pest (SPP), the most frustrating thing can be failing to locate the source of the infestation. Hours can be spent searching for the infested material. Identification can be helpful because so many SPP have a particular food source they are known to prefer, although not exclusively eat.
For example, if the pest is identified as a webbing clothes moth (Tineola bisselliella), you can be fairly sure it is not infesting the open bag of flour in the pantry. Be sure to always recommend glass or thick plastic containers for storage, however; many of the common food pests can easily chew through plastic bags, and even cardboard containers.
One more tip: Most SPP cannot harm you or your customers, even if consuming them directly. While it can be a little off-putting, the insects are not going to injure them or make them sick, so you can reassure your grossed-out customers!
from Pest Management Professional http://www.mypmp.net/2018/09/11/stored-product-pest-identification-is-key/