I think you're overstating the risk of cell culture. Trans fats, to take your example, are a side chain reaction from the hydrogenation of vegetable oils, and results in fats that were never a significant part of our diet.

Cell culture is growing more of what we've already evolved to eat.

Do I want all food tested for safety? Of course. If they were creating a brand new cell line from scratch instead of using cells we already know we can eat, I would share your concern to a much greater degree.