Fresh From the Bench: Latest Precedential Patent Case

CASE OF THE WEEK

Enviro Tech Chem. Servs., Inc. v. Safe Foods Corp., Appeal No. 2024-2160 (Fed. Cir. May 4, 2026)

In its only precedential patent opinion last week, the Federal Circuit affirmed a district court’s determination that asserted claims of Enviro Tech’s U.S. Patent No. 10,912,321 were invalid as indefinite.  In so holding, the court clarified when terms of approximation like “about” may fail to apprise a skilled artisan about the scope of a claimed numerical range.

The ’321 patent claims a method for treating a poultry carcass with peracetic acid to increase its weight.  The claims recite placing the carcass into a solution with “an antimicrobial amount” of peracetic acid, checking the pH of the solution before and after the carcass is added, and adding an alkaline source to achieve “a pH of about 7.6 to about 10” at those monitoring points.  While acknowledging that “words like ‘about’ and ‘approximately’ may be appropriately used to avoid a strict numerical boundary” (cleaned up), the Federal Circuit explained they are “not inherently definite or indefinite,” and found that on the facts of this case, the recited approximate pH range failed to reasonably apprise the public about what range was covered.

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Editors:

Nika Aldrich, IP Litigation Group Leader, Schwabe

Jason A. Wrubleski, Shareholder