Re: Food colorings in histology

From:Lee & Peggy Wenk

We've used tartrazine as a counterstain with Brown and Hopps, a
variation of Gram stain. It gives a yellow background color.
The first time I saw it used as a food coloring was in a
"Cheetos" type snack food (it wasn't Cheetos, but another
company's variation, but I don't remember the other company).
I think it's also known as yellow dye No. 5. It's used in a LOT of
things dyed yellow - cereals, dried fruit, cakes, gelatin, ice cream,
cookies, margarine,  butter, pasta, etc.
There are probably other food colorings that the FDA has
classified as GRAS (generally regarded as safe) when used
in small amounts in food, but which we as histotechs also
use to stain tissues.
I just don't happen to know the "other" names for many of
the food colorings.
Peggy A. Wenk, HTL(ASCP)SLS
William Beaumont Hospital
Royal Oak, MI 48073
Original Message -----
From: Smith, Allen
Sent: Monday, January 21, 2002 11:15 AM
Subject: RE: Food colorings in histology

   Cochineal is unprocessed carmine.  It is currently used in some soft drinks.  It is used in Mayer's alcoholic cochineal stain for whole mounts of marine invertebrate larvae.  It is also used as a nuclear counterstain in Rinehart and Abul Haj's colloidal iron stain for acid mucins (Arch. Pathol. 52: 189-194).
   I have occasionally used tartrazine (F&DC yellow #5) as a collagen stain.
Allen A. Smith, Ph.D.
School of Graduate Medical Sciences
   Podiatric Medicine and Surgery
Barry University
Miami Shores, Florida

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