I think maybe I should expand my thinking on the Safeway connection.
Safeway is a large corporation thus there are a number of suppliers, maintenance, inspection requirements to name but a few.
Safeway also delivers groceries to homes, they cater to various events, and donate left over and outdated foods.
There is maintance required on coolers, produce sprinkers, electrical, etc.
They have a distribution center as well as products comming from other suppliers, so there is a network of delivery trucks of which produce, dairy products, meats etc. are probably delivered routinely. Who are the suppliers, how does the product arrive and then leave.
Safeway is also involved in the community. Was/is there something specific going on in March? Even activities going on a regular schedule.
I would not limit it to garbage disposal, although Safeway does have a system in place regarding biohazard items, let alone every day removal of garbage, crates etc.