I have also herd of this myth. try this put a few in your hand and hold them under water until they are dead. Do this with 24 or so if they are biting your hand then you will know. I am not talking nibbles i am talking biting, they bite hard so you will know what a bite is or if they are just wiggling. use hot water this will surly set them off in such ways stomach acid will. Dont worry they cant hurt you. but their bite might be startling. i tryied this with a very large species of cricket and they bit me hard. so i stopped feeding them about 6 months later the stores stopped selling them because of that reason. meal worms will not bite near as hard as this cricket did.