Yeah, its good for them, just dont overfeed, one good sized nugget a day is enough for a baby. Watch their weight and monitor the frequency of their pooping. Its a high calorie food and a single serving goes a long way.
To be honest, crickets arent all that great or nutritious of a food, they consist of mostly undigestable parts that just pass through, though nightrawlers are a great food for frogs. Variety is always better, which is why i often give my frogs nightcrawlers and live fish (not gold fish or other feeder fish) as well as this food, but they can and do live and grow on this food alone and be very healthy.
As far as safety, all of the ingredients an be looked up online and you an see for yourself that they are safe. I think Nuance and Samurai Japan, and even Mikesfrogs success with the food being used over a prolonged period of time is testament to its safety.