Bareburger Group LLC deceives consumers by marketing burgers as “organic” when they are accompanied by non-organic ingredients, a new proposed class suit alleges.

Consumers reasonably think all parts of a food labeled “organic” are just that, New Yorker Gil Rosenberg alleges in a March 22 suit in the U.S. District Court for the Eastern District of New York.

But the supposedly “organic” fast-casual restaurants sell countless non-organic ingredients including lamb, bison, mayonnaise, and tomatoes. Some of those are “crucial condiments...