AP and Newsweak say this is an unfounded rumor.....but

Senomyx is a high-tech research business that develops flavor enhancers for consumable food, beverage and ingredient products. A senomyx chemical masks bitter flavors by turning off bitter flavor receptions on the tongue and enhancing sweet and salty (without actually tasting anything). These enhancers are used in small quantities so that they fly under the radar for labeling. Because they are not actually ingredients, but are referred to only as "flavor enhancers," they are not required to be listed as a product ingredient except as an artificial flavor.

According to Dr. Joseph Mercola, senomyx boasts that they have discovered taste receptors using HEK293, which is human embryonic kidney cells taken from an electively aborted fetus.

https://www.victoriaadvocate.com/news/health/do-you-know-nutrition-flavor-enhancer-flies-under-the-radar/article_b1f20246-6e6c-5a19-a2fb-f41393775cea.html