Hello,
I’m sure others will post as well. There’s a few smaller super markets before the French Border. There’s one by the AUC college, one in the Porto Cupecoy area by the Casino ( there’s some restaurants as well ). There’s one across from Rainbow Beach Club which has a lot of gluten free products as well as vegetarian products.
Jules bakery is up the road before the college past Fat Tony’s.
Enjoy your trip.