Bacteriophages are everywhere including on food because they help keep in check bacteria. However be aware that one bacteriophage is not the same as the next, they are all different and one will not be any use against the wrong bacteria. They are that highly specific. With the correct bacteria, they are lethal but against other bacteria they do nothing.
Russia and Eastern Europe use them and some in the US have saved their lives by importing them.
I have been looking into this myself as I have some highly resistive bacteria which nothing, including Colloidal Silver
, enzymes and numerous other things have been able to beat. Bacteriophages in combination might make the biggest difference which is why I have been researching it. The name I have come up with so far is Eliava Institute, in Tbilisi. You would need to find a way to import it without customs interfering. Read some stories about that and problems that some people had with customs.
For Colloidal Silver
you could make your own and reduce it. If you make a magnetic stirrer from a used low rpm PC fan and get a magnetic stir bar and a current regulating diode the price would be quite low. Some silver would be the most expensive item. Maltodextrin is often used to reduce ionic silver and some heat ie an oven with a ceramic or pyrex jug.