On June 13, 2025, the Federal Court (per McHaffie J) held that J.R. Simplot Company (“Simplot”) did not infringe a patent owned by McCain Foods (“McCain”) by applying an electric field to uncooked potatoes before cutting them into French fries.
McCain owned Canadian Patent No. 2,412,841 (“Patent”) until its expiry in 2021. The Patent claimed a process for treating vegetables and fruit before cooking them to reduce their resistance to cutting. The process involves applying a high electric field to the vegetables or fruit under conditions such that the resulting increase in the temperature of the vegetables or fruit is almost zero or at least sufficiently low as to not amount to a preheating step.
Claim construction and infringement
McCain’s infringement allegations, and Simplot’s defences to them, turned primarily on the construction of one essential element of independent claim 1: “high electric field”.
McCain argued the skilled person would have understood this term to include a technology known as pulsed electric field [PEF], in which an electric field of many hundreds or thousands of volts per centimetre (V/cm) is applied in short pulses typically measured in microseconds (µs). On McCain’s construction, Simplot’s potato treatment process, which uses PEF, falls within the claims of the Patent. Simplot disagreed. It argued, based on the context and language of the Patent, including the descriptions and experiments disclosed in it, that the term high electric field as used in the Patent, including in claim 1, is limited to electric fields of lower strength, that it does not cover PEF technologies, and that it therefore did not infringe the patent. Simplot argued in the alternative that if McCain’s construction were to be adopted, the Patent would be invalid for overbreadth and inutility, inter alia.
The Court held that the skilled person, reading claim 1 in light of the common general knowledge and in the context of the Patent as a whole, would have understood the claim term “high electric field” to mean an electric field within the specific range of 2 to 200 V/cm. Based on this construction of “high electric field”, the Court concluded that Simplot did not infringe because it found as a fact that Simplot used fields that were about ten times higher. The Court relied on evidence led by both parties in reaching this conclusion.
Invalidity
In obiter, the Court held that claims 1 and 6 would be invalid for overbreadth and for lack of utility if the claim term “high electric field” were to be construed in the manner proposed by McCain, namely, that it included Simplot’s process using PEF.
On overbreadth, the Court held that the asserted claims were broader than the invention made or contemplated by the inventors. The inventors of the Patent, in coming to their invention, did not contemplate a process that involved the application of electric fields of the high voltage used in PEF treatments. Rather, the process that they did contemplate and invent was limited to the application of electric fields of much lower strengths. The Court made this finding of fact based on the Patent itself, inventor testimony, contemporaneous documents, and expert opinions.
On utility, the Court held that the inventors had not demonstrated or soundly predicted by the filing date that the claimed process using PEF would have the claimed utility, i.e., would reduce resistance to cutting without increasing temperature across the full scope of the claimed range. The inventors had not demonstrated the utility of applying electric files ten times the strength of the highest field tested, and did not have an articulable and sound line of reasoning to predict the utility of those voltages in reducing cutting resistance. The Court relied on inferences and trends from the inventors’ studies, prior art, and expert evidence in making this finding of fact. There was also insufficient disclosure of the inventors’ alleged line of reasoning in the Patent.
Expert evidence
The Court made two holdings of interest in respect of the expert evidence adduced by the parties. The first was that opinions on the attributes of the skilled person and of that person’s common general knowledge at the relevant date is admissible even if the expert does not opine on the issues of claim construction or invalidity. The second was that the Court need not accept any of the experts’ opinions on construction, but can reach its own conclusion on the meaning and scope of the patent’s claim.
Conclusion
McCain’s action was dismissed. The Court awarded costs to Simplot in the agreed amount of $1,700,000 CAD, inclusive of all fees, disbursements and taxes. McCain has 30 days from the date of judgment to file an appeal in the Federal Court of Appeal.