ABSTRACT.Using a very simple subharmonic argument we prove that a Banach Jordan algebra is Hermitian if and only if the sum of two positive elements is positive. We apply this result to give a characterization of Banach Jordan algebras with involution which are JB*-algebras for an equivalent norm.If B is a complex Banach algebra with involution, the Shirali-Ford theorem states that every selfadjoint element of B has real spectrum if and only if x*x has positive spectrum for every x in A. In particular this theorem implies that such an algebra has many Hilbert space representations.The corresponding problem in Banach Jordan algebras is also important as if a Hermitian algebra is symmetric it is possible to make use of the representation theory for JB-algebras given by Alfsen, Shultz and St0rmer in [1]. A solution to this problem was given by Behncke in [5] but the argument he used, while containing a nice idea, is rather long. The aim of this paper is to give a simple proof of Behncke's result using a subharmonic argument and to give an application to the characterization of JB*-algebras. Instead of working with real Banach Jordan algebras throughout this paper we shall let A denote a complex unital Banach Jordan algebra with involution and S shall denote the real linear subspace of selfadjoint elements of A. As for Banach algebras, if o G A one can define the spectrum and spectral radius of a; these will be denoted by Sp(a) and p(a), respectively. Some standard properties of Sp(o)