mislabeling nut ingredients doesn't justify class action because not everyone has nut allergies

Fukaya v. Daiso California LLC, No. 23-cv-00099-RFL, 2025 WL 2644747 (N.D. Cal. Sept. 15, 2025)

Fukaya, who is allergic to tree nuts, alleged that Daiso failed to properly label its pre-packaged food products as containing tree nuts on its English-language ingredient lists, alleging the usual California statutory claims and breach of express warranty. The court denied Fukaya’s motion for class certification: individualized questions regarding reliance, causation, and damages were likely to predominate because the classes, as defined, were not limited to purchasers who are allergic to tree nuts or buying for others with such allergies.

Fukaya allegedly suffered a severe allergic reaction after eating a cookie she purchased from a Daiso store. The English translation of the ingredient list did not list any tree nuts, but the Japanese ingredient list (which was covered by the English translation) listed two tree nuts: almonds and hazelnuts. Later, she bought a different product that had an English ingredient list which did not list any tree nuts, covering a Japanese ingredient list that listed almonds. She alleged that she “would go back and purchase more pre-packaged food products from Daiso ..., but [is] concerned about the accuracy of the English language sticker labels.”

The problem was lack of evidence that “the omission of tree nuts from the English language ingredient list would be material to an objective reasonable consumer.” Certainly, a reasonable consumer with a tree nut allergy would find the omission material, but the proposed classes weren’t limited to purchasers who have tree nut allergies or are buying for others with those allergies. Because materiality wasn’t shown to be susceptible to classwide proof, individualized issues would predominate with respect to the elements of reliance, causation, and damages for each of her claims.

Fukaya argued that individualized issues do not predominate with regard to her UCL claim because, under the unlawful and unfair prong of the UCL, she need not show reliance. “However, even under the unlawful and unfair prongs of the UCL, a plaintiff alleging a misrepresentation must prove reliance in order to establish causation and harm.” Footnote: even if reliance weren’t required, the unlawfulness theory would be preempted by the FDCA.

Fukaya also failed to show that individualized questions would not predominate with respect to damages calculations. She didn’t present a damages model or theory of class-wide recovery, stating only that the calculation “will be a simple mathematical task, or one that Daiso itself can and has generated.”

Fukaya’s counsel declined to request a modification of the class definition, given the cost of litigation, and there was no evidence about numerosity for a nut allergy class. Nor could there be an injunctive relief class, because “Fukaya has not carried her burden of proof with respect to the existence of a pattern or practice of widespread mislabeling sufficient to satisfy Rule 23(b)(2).” At the motion to dismiss stage, the court ruled that Fukaya’s purchase of two similarly mislabeled products “supports an inference that other products are also mislabeled.” But at class certification, a plaintiff may no longer rely only on allegations that could permit plausible inferences in her favor. The existence of two mislabeled products was insufficient for the court to find that Daiso “acted or refused to act on grounds that apply generally to the class.”