Is it permissible to accept lunch or tea invitations from officials of contracting companies, especially if the work discussion will take place at the dining table?

"That which is specific to you and hints at an intention to influence you and gain your favoritism, it is not permissible to accept it, for it is a bribe. As for that which is general and the possibility of an intention to influence is unlikely—due to common practice or its trivial nature—there is no harm in it."