Moo, its hardly antiquated. Discus breeders would not be ending up with some of the incredible fish they do if the beef was bad for the fish. The largest problem with beef, is making sure its hormone free as the hormones can effect the fish in the same ways as color enhancing hormones such as Methtestosterone do, by destroying internal organ, and or causing infertility. Beef is one of those tried and true foods for discus, I use it as a back up, but most large breeders aren't willing to get shrimp at $7/lb when they get beefheart for $1/lb or burger for $2/lb. The beef works, and is a healthy food for them (in all honesty there has probably been more research done on feeding discus for growth and health than any other fish out there, many of the Asian breeders have college education dealing specifically aimed at the production of tropical fish and understanding their needs, massive in house studies about feeding has been done with the big breeders over there) so until there is a conclusive amount of scientific proof provided that beef is infact harmful to the fish, I will keep advocating using it.
The binding agent in the shrimp mix I use, isn't the egg yolk. The shrimp itself acts as an incredible binder, holding the vitamins, calcium and the egg yolk itself. Its probably one of the cleanest foods available. Egg yolk is extremely water soluable, and has the potential to foul water very quickly, but its also an excellent source of nutrients for fish, using the shrimp, the egg yolk is held to the shrimp, and won't have a negative impact on the water quality unless sitting in the tank for quite some time. Both of the food mixes, beef and shrimp, won't cloud the water one bit, both are extremely clean.
Moo I would also reccomend trying the shrimp mix with the apistos, any carnivorous fish can really benefit from that food. Is an excellent fry food, and just as good as a staple diet.