(Reuters) — Consumers may join class action lawsuits against Microsoft Corp. and Infineon Technologies A.G. over allegations of unfair pricing for computer products, the Supreme Court of Canada ruled on Thursday.

The high court refused to allow a class action to proceed against Archer Daniels Midland Co. and Cargill Inc. over alleged price-fixing on high-fructose corn syrup used in soft drinks and baked goods.

The Supreme Court, in linked decisions on Microsoft and Infineon, certified separate class actions against the companies.

The cases dealt primarily with whether consumers have the right to join a class action even if they were only indirect purchasers, not buying directly from the companies involved. None of the cases were at the point of establishing liability.

The class suing Microsoft is any British Columbia residents who bought Microsoft operating systems or applications software for their own use from 1994 on. Typically, once the principle is established, suits could be launched in other provinces.

The suit in Quebec against Infineon alleges that it conspired to inflate the price of a broadly used product, dynamic random-access memory chips (DRAM), used in computers made by companies such as Dell Inc. and Hewlett-Packard Co .

The companies argued that if both the consumers and the retailers or intermediaries who sold those products were allowed to recover damages, the companies risked having to pay the same damages twice.

In the Microsoft and Infineon cases, the court said the risk of duplicate recoveries could be managed by the courts.

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In the decision on ADM and Cargill, the court agreed that while class actions by consumers can proceed in principle, consumers would not be able to identify what sweetener was used in each fruit drink or baked good they consumed over the years. A class action cannot therefore be certified, it ruled.

"We are pleased with the court's decision as we have always viewed this lawsuit as lacking merit. We will continue to invest in our Canadian business operations to better serve and support our customers in Canada," Cargill spokeswoman Nicole Reichert said in an email.

Microsoft voiced optimism that the lawsuit itself would be defeated. "We are confident that we will prevail when the case is considered on the merits," Microsoft Deputy General Counsel David Howard said in an email.

Other companies had no immediate comment.