Salvage of too slow gravitinos

Gravitinos can inherit a non-relativistic dispersion relation while propagating in background breaking both supersymmetry and Lorentz symmetry spontaneously. This is because the longitudinal mode velocity controlled by sound speed background. It was pointed out recently Kolb, Long McDonough that production of gravitinos might diverge when this vanishes. We argue framework cosmological models with linearly spontaneously broken realised supersymmetry, where physical fermions are combinations vacuum goldstino inflatino, gravitino has relativistic therefore avoids catastrophic production. illustrate some explicit examples.