Colgate Kitchen was real. A 1966 trade-press account described a short-lived line of Colgate-branded entrees made with dried chicken and crabmeat. The company wanted a foothold in convenience foods; the meals were introduced and quickly withdrawn.
The famous Colgate Beef Lasagna box circulating online is not historical packaging. Museum of Failure says its display was reconstructed with “a good measure of artistic freedom.” So the genuine story is odd enough: Colgate tried to sell dinner. The lasagna people remember is a modern mock-up that made the story even more ridiculous.
Sources: Television Age (1966), Colgate-Palmolive profile; Prospect, “What a viral fake lasagne taught me about failure”; Museum of Failure, “Colgate Kitchen Entrees”.
Image: “New Colgate Dental Cream with Gardol,” Photoplay (November 1954), via Wikimedia Commons; public domain in the United States. Illustrative Colgate advertisement, not a picture of Colgate Kitchen food.