As far as search engines are concerned, it is doubtful it will have any effect, unless the font color exactly matches the page background color.
My advice for "
SEO" issues is design a page with the visitor in mind, not the search engines. If the average visitor can not read the text, for whatever reason, then there is no point is using that text.
By the way, white text on a black background is not comfortable for the eyes. It is much easier for the eye to have black text on a white background.