It's not about the certificate, its about what they use to derive the whey from the milk by using rennet. Rennet usually comes from animals, and when animals are not slaughtered accordingly to a Muslim way, anything from meat to enzymes are considered haram.

When haram rennet is used in curdling whey from milk, this falls into a haram state.
Dude whats up with the caps?

Muscle juice contains whey which is derived from milk by mixing rennet. If the animal is slaughtered by chopping their heads off without the Islamic way, its considered haram. This implies to the rennet aswell.

By the way, we could consume anything without a certificate if you didn't know that. The certificate or the halal logo if you would call it is just there to ease Muslims to consume the food without asking where the source is.

And yes the milk from the cow nipples doesn't need a freaking certificate or some hocus pocus ritual prayers.