Brown stripes in a white print

New to the world of 3D printing, I have an Anet A8, am running mostly stock with minor improvements. I am using white GeeeTech PLA with a temp of 185 and a heated bed at 60, but am getting brown striping throughout my recent prints. Print quality is generally fine but i?m At a loss as to what it causing this. I?m guessing this is perhaps burning of the filament but haven?t noticed any temp changes. Any idea?s about where to look for this? Am using Cura to slice. Thanks

Example of what i’m seeing.
Attachment 11969

would guess contamination of the filament during manufacturing

thanks for the suggestion, hadn?t really considered that. you don?t think its possibly a faulty hot end/ thermister?

pretty unusual - try a different make of filament.