They are probably grain mites. They would probably have been in the foods packaging, or in the storage container you use, check the expiration date on the food you bought. While they will not make your hamster sick, I would suggest you thoroughly clean up your house unless you want to live with them.
Start by cleaning out the food itself. If there's too many to remove, throw out the entire feed, clean the container by washing it. Then, clean the hamsters cage extremely carefully. They carry their food in their mouth and store it here and there, so make sure you get every hiding place cleaned otherwise the mites will come back. Also do a thorough cleaning of the house. Use bug spray that is not toxic to animals.
Watch your hamster for diarrhea of vomiting, although I doubt the mites will have harmed it. Next time, get the feed from a good pet store, make sure it's fresh, and if possible, look for any insects in it before you buy it.
Start by cleaning out the food itself. If there's too many to remove, throw out the entire feed, clean the container by washing it. Then, clean the hamsters cage extremely carefully. They carry their food in their mouth and store it here and there, so make sure you get every hiding place cleaned otherwise the mites will come back. Also do a thorough cleaning of the house. Use bug spray that is not toxic to animals.
Watch your hamster for diarrhea of vomiting, although I doubt the mites will have harmed it. Next time, get the feed from a good pet store, make sure it's fresh, and if possible, look for any insects in it before you buy it.