To whose 'salt' is the idiom, "worth one's salt" referring to?
Dale: Every journalist worth his or her salt (worth paying to do his or her job) should ask probing and challenging questions.
Dale is referring to the journalist.
We used to pay people in salt. That's where the word salary comes from. If you're worth your salt you're worth your pay.
Salary
Middle English: from Anglo-Norman French salarie, from Latin salarium, originally denoting a Roman soldier's allowance to buy salt, from sal ‘salt.’
google: etymology of the word salary