I am fastidious in handling Rio and Chance's food. In handling raw food, the only rules are that you handle them as if you are going to eat it yourself. So you thaw it just before you feed it, you keep leftovers refrigerated only for perhaps a day, and you don't leave it lying at room temperature where the bad bacteria can flourish. Carnivores have an amazing gut flora that can deal with more bacteria than we can, but still, I'm cautious. Too much bacteria can be harmful to some extent (like giving them diarrhea) but for the most part, it's quite safe. I wash their dishes every day, keep the counter wiped clean etc. I grew up on a farm (I tell me I grew up eating manure) so I know I have a strong immune system. When I clean I use vinegar and water for the most part. If something really scares me I'll use water with a bit of bleach in it, but I'm not too paranoid about bacteria...just cautious in a very normal way.
I give both Rio and Chance ground raw food because it is readily available and it is convenient for me. I don't think I could grind fish either. For myself to eat, I like fish that doesn't smell like fish (so very, very fresh) and that has a very mild taste...so I can't handle eating the stronger, oilier fishes. But my cat and dog love them so I buy it, but I can tell you that I thawed some in the microwave one day for the cat and I'll never do that again. I almost threw up when I took it out...it had a vary strong smell when warmed up.
There is lots of info online about feeding raw, so if you google it you'll find it. It wouldn't surprise me to find a raw fed ferret site if I were to look!