That’s just throwing more probabilities at the problem, and it doesn’t even solve it. You don’t need horrible nerve agents to kill someone by ingestion, it could simply be something the eater has a sufficiently nasty allergy to. And again, replicators aren’t limited to food.
The better idea is the simplest one: Don’t replace the perfectly functioning replicators.
The better idea is the simplest one: Don’t replace the perfectly functioning replicators.