nope; it's not okay, and your employer is guilty of a misdemeanor.
California regulations 8 CCR 11070 (which apply to mercantile operations) says, in part:
11. Meal Periods.
" (A) No employer shall employ any person for a work period of more than five (5) hours without a meal period of not less than thirty (30) minutes, except that when a work period of not more than six (6) hours will complete the day's work the meal period may be waived by mutual consent of employer and employee. Unless the employee is relieved of all duty during a thirty (30) minute meal period, the meal period shall be considered an “on duty” meal period and counted as time worked. An “on duty” meal period shall be permitted only when the nature of the work prevents an employee from being relieved of all duty and when by written agreement between the parties an on-the-job paid meal period is agreed to."
Basically, if you work more than 6 hours in a day, you must get at least one 1/2 hour meal break and a couple of 10 minute rest breaks.
these rules are supposed to be posted at your workplace (look for the Industrial Welfare Commission Wage Order poster in the coffee/break room).
more questions? call the Labor Commissioner at 415-557-7878 or visit them on the web at:
http://www.dir.ca.gov/DLSE/dlse.html
good luck.