{blackbabes} Mariah Carey Twins Probe -- Case Closed

The L.A. County Department of Children and Family Services has just wrapped up its interview with Mariah Carey and has concluded there is no merit to the investigation -- sources connected with DCFS tell TMZ.

We're told DCFS social workers interviewed Mariah and spent time with the twins -- and concluded the children were in a healthy and safe environment.

The investigation was triggered by an anonymous phone call to DCFS complaining that Mariah drank a Guinness beer while she was breast feeding.

As we reported, Mariah was informed by a hospital staffer that drinking a dark beer would assist her in lactating. We're told Mariah informed social workers she simply followed the hospital staffer's advice and drank the Guinness, never hiding the fact that she consumed the drink.

We're told Mariah's lawyer, Laura Wasser, was present during the DCFS interview today.

Our DCFS sources say officials have concluded there is no merit to the complaint.