WHEN THE CHIPS ARE DOWN: Federal Court of Appeal Dismisses McCain’s French Fry Process Patent Appeal

In a decision read directly from the bench on April 14, 2026, the Federal Court of Appeal in McCain Foods Limited v J.R. Simplot Company, 2026 FCA 71 dismissed McCain’s appeal in respect of a patent directed to the process of using an electronic field to treat vegetables and fruit prior to cooking, in a manner that reduces resistance to cutting. McCain, the patentee, and the respondent, J.R. Simplot Company, are competitors in the French fry industry.

The crux of the appeal centered on whether the Federal Court erred in its construction of the claim term “high electric field.” The trial judge had found that the skilled person would have been aware that this term had no established definition in the art, but nevertheless found the skilled person would understand the term to refer to electric fields in the range of 2 to 200 volts per centimeter [V/cm]. The trial judge thus reached a finding of non-infringement on the basis that Simplot’s technology uses a pulsed electric field in the range of 1,000 V/cm or more. The trial judge additionally found that even if the term could be construed to capture the technology used by Simplot, then the claims at issue would be invalid for overbreadth and lack of demonstrated or soundly predicted utility.

To begin, the Federal Court of Appeal rejected McCain’s submission that the trial judge’s construction should be reviewed on a “correctness” standard of review. The Court of Appeal explained that, while in theory construction of a patent claim is a question of law, when the construction turns on expert evidence as to the skilled person’s understanding of the claim, the standard of palpable and overriding error applies.

Next, the Court of Appeal assessed whether the trial judge committed a reviewable error in his construction of “high electric field.” McCain made several submissions on this point, including that the Federal Court imposed a rigid numerical limit on the term when the patent did not do so, that the Federal Court prioritized the disclosed embodiments for the construction of the term, and that the Court ignored discussion within the disclosure purportedly connecting pulsed electric fields to beet sugar extraction.

The Court of Appeal rejected McCain’s submissions, finding that the trial judge did not commit an overriding and palpable error in the patent construction analysis. First, the Court of Appeal found that the Federal Court undertook an extensive analysis of the claim term, considering both the common general knowledge in the area of electric fields as well as the impact of electric fields on plant tissues and food processing. This analysis was informed by both the language of the claims and consideration of the claims in the context of the specification. Second, the Federal Court rightly considered the preferred embodiments as part of purposive construction and moreover acknowledged that claims are not limited to the preferred embodiments of the disclosure. Third, the Federal Court was entitled to find that the skilled person would not read the reference to beet sugar extraction in isolation from the rest of the disclosure, and moreover was equally entitled to find that the skilled person, taking into account their common general knowledge of electric fields in fruit and vegetable preparation, would not make the connection to pulsed electric fields as put forth by McCain.

The appeal was thus dismissed, with Simplot awarded all-inclusive costs of $30,000, as had been agreed upon by the parties.