Bacteria the chicken eats do NOT get in the eggs while the eggs are forming inside the hen.
Bacteria in the nest or on the outside of the hen could get on the outside of the eggs. Bacteria on the outside of the eggs might get to the inside of the eggs in some circumstances (wet eggs, or when...
Fat is the only problem I know about.
If there is another problem with them, I have not heard of it.
You didn't say how many mealworms or black soldier fly larva you were feeding or planning to feed, and overfeeding with them is easy to do, so we were warning to be careful.