In McCain Foods Limited v. J.R. Simplot Company (2025 FC 1078), the Federal Court of Canada ruled that Simplot's use of pulsed electric fields (PEF) to pretreat potatoes for French fry production did not infringe Canadian Patent No. 2,412,841 (the "'841 Patent") held by McCain. The decision centered on the interpretation of the term "high electric field," with the Court ultimately determining that the term referred only to electric fields between 2–200 V/cm and did not extend to the much higher field strengths used in PEF processing, which can exceed 1,000 V/cm.
The Court also held that even if McCain's broader interpretation of the term were accepted, the asserted claims would be invalid due to overbreadth and inutility. The findings raise important issues related to expert evidence on common general knowledge (CGK), claim construction, and the legal standards of validity.
Admissibility of expert evidence on CGK
McCain challenged the expert opinion of Dr. Vorobiev, Simplot's technical expert, arguing it was inadmissible because he had not construed the patent claims. The Court rejected this, finding that expert testimony on the CGK is relevant and admissible, even if the expert does not address the legal interpretation of claims. Citing Whirlpool, the Court emphasized that an expert's role is to help the judge understand the context, not to interpret claims directly.
Claim construction: "High electric field"
The term "high electric field" was central to the infringement analysis. McCain argued for a broad interpretation encompassing any electric field that reduces cutting resistance. Simplot contended that the term referred only to low-voltage, non-pulsed electric fields.
The Court sided with Simplot, noting that the '841 Patent described fields between 30–75 V/cm for durations of 1–10 seconds and did not refer to pulsed applications. In contrast, PEF treatments involve much higher voltages applied in microsecond pulses, technology not contemplated by the patent. As such, the Court held that Simplot's use of PEF did not infringe.
Invalidity on overbreadth and inutility
The Court further found that if McCain's broad interpretation were adopted, the claims would be invalid. The inventors had neither tested nor soundly predicted the utility of PEF treatments using much higher voltages and drastically shorter durations. The Court emphasized that PEF represents not just a difference in degree, but a difference in kind, requiring distinct equipment and having different effects on plant tissue.
The Court also rejected McCain's argument that claim 1 was inherently limited to useful embodiments, calling it a tautological attempt to sidestep the patent's utility requirement.
Simplot was represented by Daniel Davies, Jean-Sebastien Dupont, Matthew Norton, and Emily Miller of Smart & Biggar.
Source: Smart $ Biggar
