"Canned Maine Sardines in Mustard Sauce" is the commercially canned product prepared from immature Atlantic herring (Clupea harengus); packed with a suitable quantity and quality of mustard sauce in hermetically sealed containers and so processed by heat as to prevent spoilage. The mustard sauce ingredients shall conform to Federal Specifications of purity and be free from adulteration. Immature herring means herring of which less than fifty percent (50%) have well developed gonads and may or may not have spawned.
01-001 C.M.R. ch. 338, § I-1