Maybe that would be enough. But the belt-and-braces approach of superglue with silica gel bags in a closed jar, in a fridge, seems to work well and has meant the superglue is still usable when I end up needing it....

Yeah don't. Like many metals, finely dispersed iron can self-combust on air. I'd suggest an air-tight packaging filled with CO2, or, if your food is susceptible to acid, N2, if at all feasible. Industry uses additives similar to hydroquinone, mixed directly into, e.g., plastics. Plenty of them are food-safe, but I wouldn't know where to buy them if you aren't a business.

I think a lot of us might even confuse the two. The packets look fairly similar too.