[tallanvor]

The anti-caking ingredient has a negligible effect on flavor. Where you want to avoid them is when you're cooking a dish where you want the cheese to melt smoothly. Using the pre-grated stuff is fine for things like tacos, burritos, pizza, and even omelets. For stuff like mac and cheese and other cheese-based sauces, that's where you want to grate your own if you can. --And if you can't, well, the food will probably taste just fine even if it doesn't look quite as good.