california inspection of grapes

From a California DFA letter. Generally, the Food and Agricultural Code requires the inspection of fresh grapes destined for wine and byproducts be inspected by either the Agricultural Commissioner, OR the California Department of Food and Agriculture (CDFA) if either soluble solids, rot, or material other than grapes (MOG) are used to set the purchase price of grapes. These requirements apply to all vintners/processors and their growers, regardless of whether they participate in the California Winegrape Inspection Marketing Agreement or not.

Do most wineries utilize the CDFA for inspection of grapes? I was interested in how many wineries participate in this program.What is the experience of grape growers with the program? I ask these questions because in the East some wineries like to use a contract that was put together by Virginia Tech that contains the possibility of adding percentages for rejection of the grapes based on rot and MOG. My question to wineries has always been by whom and how is the determination going to be made? Can you determine the difference between 3 and 4% rot? That subtle difference could lower the price. I know of no standard method for determining the percentage of rot or MOG in a bin or container of grapes.