This morning (Thursday August 1 before 9:00AM), I found somebody's groceries on the red line train between Downtown Crossing and South Station, I believe. (I get on at Downtown Crossing and off at JFK/UMASS). I did not pay attention to which train I got on, but I think it was outbound to Braintree.
The groceries were in a white Market Basket bag. It was a tub of cottage cheese and a can of pineapples. I opted not to turn it in to Lost & Found, presuming they could not refrigerate it.
If yours, feel free to call me at: 617-645-6776