If your worried about food stream contamination i probably would not. Pet foods are not held to the same standards as food for human consumption. Its one thing to use worms that are farmed in captivity and another to use wild caught or farmed shrimp that live in a river with unknown contaminants. I know this is a somewhat patinoid outlook but its something to think about. As a whole, store bought eggs are much safer because the birds are raised in a controlled environment. A little research on lead contamination in poultry yeilds horrifying stories about poultry that are raised on a homestead free range finding lead contaminents, either from shooting or lead paint ect that happened 3 owners ago. The current owners feed the "super healthy free range eggs" to their kids and neighbors and actualy are poisoning them with lead. I have also heard anecdotal reports of oyster shell contaminated with lead. I was talking to a miner just last week and he said all the ore that comes out of the mine gets shiped to china where the metal is leach out with chemicals. The point I'm making is china has no EPA, who knows what sort of chemicals are in their rivers.