I dont know how it is in aus but in uk all additives are given an E number. Just because its an additive it doesnt mean its bad, or even unnatural.
There was a tv prog on the other week about them and the presenter trying to OD on them. Doc was more worried about sugar and fat content.
Personally, i keep away from any microwave meals, make all my meals from scratch (cept for the few takeaways i have) so i know most that goes in it.
Anything that doesnt agree with you, keep away from those, and thats about as much as i worry about foods