For millions of Muslims, the holy month of Ramadan marks a time for ritual fasting and, often, a large meal with friends and family after sundown.

For those buying and selling ritually approved halal meat, it's a time to ensure the food the observant are eating is exactly that.

It's harder than it sounds, and some critics raise questions about whether the doctrine of church-state separation means governments should even get involved. That means policing is sometimes up to the meat sellers themselves.

Gul Muhammad opened a halal meat shop in New Jersey this year. He says he visits farms and slaughterhouses to make sure the animals are being slaughtered according to the religious standards generally adhered to by the world's estimated 1.6 billion Muslims.