  In this workshop we have presented the results obtained in the three-flavour
($N_f=3$) Nambu--Jona-Lasinio model Lagrangian which includes all
non-derivative vertices at NLO in the $1/N_c$ expansion of spin zero
multi-quark interactions. In particular the role played by the explicit chiral
symmetry breaking interactions has been discussed in comparison with previous
model Lagrangians.
