Cal. Food & Agric. Code § 66626

Every handler is primarily and personally liable for the payment of an assessment. Any handler who fails to file a return or pay any assessment within the time required by the commission shall pay to the commission a penalty of 10 percent of the amount of the assessment determined to be due and, in addition, 2 percent interest per month on the unpaid balance. The penalty and interest are required to be paid to the commission and are available for expenditure in the same manner as an assessment.