King British food is pretty cheap, and since they're cagey about their ingredients, I would be even less inclined to trust it.
Don't forget that cories go mad for algae wafers, but that doesn't mean it's good for them!
@Byron will say that they need a mostly meat based diet, and for that to be mostly insects, not things like blood worms.
Bug Bites is one of the best foods, since it's made from real insects and doesn't contain a load of cheap filler. I personally can vouch that my cories (bronzes, sterbai and pygmy) all eat Bug Bites with relish, as do the other fish in their tanks.
ETA: It's also not an expensive food!