Accessibility – How to measure color contrast in anti-aliasing?

What is the correct method for measuring the color contrast of screen elements that are anti-aliasing (especially text but not limited to text)? Is there a standard method at all?

Here is my specific situation: I'm trying to maintain WCAG 2.0 for text in a drop-down menu. An enlarged screenshot of the menu is below:

zoomed screenshot of anti-aliasing around text

This is a standard IE11