Effect Of Prosecution History On Preamble Interpretation

Of course interpretation of a preamble can be significantly affected by the prosecution history. Clear reliance on the preamble during prosecution of a patent to distinguish the claimed invention from the prior art can be a strong indication that the preamble is a claim limitation. In the "broccoli" case , for example, the Federal Circuit considered three patents related to growing and eating sprouts to reduce the level of carcinogens in animals. The relevant claims included:

(5725895 claim 1) A method of preparing a food product rich in glucosinolates, comprising germinated cruciferous seeds, with the exception of cabbage, cress, mustard and radish seeds, and harvesting sprouts prior to the 2-leaf stage, to form a food product comprising a plurality of sprouts.

(5968567 claim 1) A method of preparing a human food product [comprising desirable compounds from sprouts].

(5968505 claim 16) A method of increasing the chemoprotective amount of Phase 2 enzymes in a mammal [by creating a "food product" from sprouts and then "administering said food product" to a mammal].

In interpreting those claims the Federal Circuit found that the preambles did constitute limitation on the scope of the claims, largely based upon the following language from the patent prosecution:

Claim 1 of the patent, for example, is directed to "[a] method of preparing a food product rich in glucosinolates... and harvesting sprouts prior to the 2-leaf stage, to form a food product comprising a plurality of sprouts".... Although "rich in glucosinolates" is recited in the preamble of the claim, the pertinent case law holds that the preamble is given weight if it breathes life and meaning into the claim.... Accordingly, the cited prior art does not anticipate the claims because it does not explicitly teach a method of preparing a food product comprising cruciferous sprouts that are rich in glucosinolates or contain high levels of Phase 2 inducer activity.