Tuesday's one-day strike includes nurses, physicians assistants and dental assistants at Santa Rita Jail in Dublin and Glenn Dyer Detention Facility in Oakland.
The workers say Tennessee-based Prison Health Services has not been negotiating a new contract in good faith and has backtracked after agreeing to a 10-percent increase in wage and health care benefits. They say the company now wants to increase health care premiums by 30 percent.
The current contract expired in December.
Alameda County pays Prison Health Services $25 million a year to provide medical services.
Company spokesman John Van Mol says it remains committed to negotiating a fair, reasonable and competitive contract.
