 This study investigates the existence of non-classical correlations resulting from the quantum character of spontaneous Hawking radiation in a sonic black hole scenario where an atom condensate flows through a subsonic supersonic interface and concludes that only the violation of quadratic Cauchy-Schwart's inequalities can be discerned within a class of detection schemes. This article was authored by J. R. M. Danova, F. Solz, and Isopota.