Yes, anyone can download the TE-FOOD Consumer app, and check TE-FOOD labels. And exactly as you wrote, you can be able to trace back the food products until they reached America in that case. But it depends on how the food products are sold in retail.
An example: Vietnam is one of the biggest exporter of Pangasius fish. A massive amount of Pangasius fish is exported to Europe. If the European importer buys the fish pre-packaged, then the TE-FOOD label stickers will be on each package, so European consumers can check the origin information. But if the fish is bought in bulk, and the retail packaging is done in an European food processing plant, then no TE-FOOD label will be applied to the retail packages.
We focus on emerging markets, but we don't refuse customers in other markets. In the example above, it can be wise for us to contact the European importer to join TE-FOOD, so they can provide full traceability for the fish products, which is a business advantage for them.
And you are right with RFID. RFID is a great technology, but in the livestock and fresh food industry it is used only on cattles in developed countries, because they live longer, and they are more expensive. For anything else, RFID is way too expensive.
It will be crucial to get the importers onboard. Most of the food gets packaged locally due to local legislative reuqirements (e.g. in the province of Quebec in Canada by law the packaging must include French, etc). However, I have already seen packaged berries (strawberries, etc) with QR on the package (which was promoting the producer and not for traceabilty), so I assume it woildn't be hard to get them to do it. But if they are not aware that this featue exists, they won't incorporate it in the packaging.
As you mentioned, the consumers in the developing countries are not cocnerned that much with the food they are buying, so it might take a while for this to pick up. But in America this is huge - I can easily see 200 000 000+ americans using the app at the grocery stores if there are enough stamped products on the shelves.
I hope the ICO is a success that would allow/convince you to expand beyond your target market.