I've had full size vans for 25 years and have always been the primary grocery shopper. I remember having to retrieve about 50 baby food jars out of all the footwells and under seats when my son was a baby and the bags opened up and the jars went for a ride

I shop at Costco a lot these days, and simply keep a couple cardboard boxes in the back of the van (which is what Costco gives you). When I go to the regular grocery store, I just load any precarious stuff into the boxes. Another alternative is a big polyethylene recycling tub (that use to cart empty cans/bottles back to the grocery store). I use that to contain groceries.

If I ever need the room, I just ditch the resident cardboard boxes and replenish the next time I go to Costo. But more often than not, the boxes are handy for other stuff, like keeping a moving quilt in, boxes of tools or bungie cords, etc.

With high back bucket seats, I don't worry too much about flying groceries if I ever did hit anything hard. There is that old joke "vans are handy--if you ever need anything from the back, just hit the brakes hard and it will hit you in the back of the head."

George