I believe they will sell retail if you contact Linda, the link provides their email and a toll free number to call. Or, Linda has a YT account (ivsanbernard), you could try PM'ing but probably better to just call.....she's always called me back quickly.
The PEK may be a little more difficult to obtain than most of the shampoo/conditioner lines out there....but it's well worth the trouble! Also, it's not cheap, comparable to Isle of Dogs prices, only it works where as I didn't care for Isle of Dogs. The product does go a long way, I've got the big jar of PEK and it's lasted now for a year and I've still got several months usage left from the same container
It's possible to find at some dog shows....just contact them and find out where they will be next.
Contact Us : Iv San Bernard (USA & Canada), Fine Italian Pet Grooming Products and Equipment